The document discusses heat and mass transfer. It outlines objectives related to understanding thermodynamics and heat transfer mechanisms. The key mechanisms of heat transfer are conduction, convection and radiation. Heat transfer occurs through these three modes simultaneously in many practical systems. Fourier's law, Newton's law of cooling, and the Stefan-Boltzmann law govern conductive, convective and radiative heat transfer respectively.
1) Heat exchangers are devices that transfer thermal energy between two or more fluids without mixing the fluids. They are commonly used in industries like petroleum refining, power plants, and HVAC systems.
2) Heat exchangers can be classified based on fluid flow patterns (parallel, countercurrent, crossflow) and heat transfer methods. Countercurrent flow is the most efficient as it produces the highest temperature changes in each fluid.
3) Common types of heat exchangers include tubular (shell and tube, concentric tube), plate (flat plate, spiral plate), and extended surface heat exchangers. Tubular heat exchangers involve one fluid flowing inside tubes while another flows
This document provides an introduction to heat transfer and thermodynamics concepts. It discusses how heat transfer is related to thermodynamics and distinguishes between different forms of energy. The three main modes of heat transfer are conduction, convection and radiation. Heat is defined as the transfer of energy between two systems due to a temperature difference, and will flow from the higher temperature object to the lower temperature one. The document provides objectives and outlines concepts like thermal energy, mechanisms of heat transfer, Fourier's law of conduction and applications of heat transfer.
1. The document discusses vapor compression refrigeration systems (VCRS), which are the most commonly used refrigeration systems. In VCRS, the refrigerant undergoes phase change and the refrigeration effect occurs during evaporation.
2. VCRS have higher efficiency and smaller size than air refrigeration systems for a given capacity, but have higher initial costs and issues with refrigerant leakage.
3. The standard VCRS cycle introduces irreversibilities from isenthalpic expansion and non-isothermal heat rejection, lowering its COP compared to the ideal Carnot cycle. Subcooling and superheating can improve the cycle efficiency.
Heat exchangers transfer heat from one fluid to another without direct contact between the fluids. The most common type is the shell-and-tube heat exchanger, which consists of tubes in a shell container. Fluids flow inside the tubes and outside in the shell. Other key types include double-pipe exchangers, plate-and-frame exchangers, air-cooled exchangers, and spiral exchangers. Spiral exchangers have two fluids spiraling in opposite directions to enhance heat transfer.
This document provides an overview of heat pipes and their applications in electronics cooling. It discusses the basic components and operation of heat pipes including the evaporator, condenser, wick and working fluid. The key advantages of heat pipes are their high thermal conductivity and ability to transport heat efficiently. Limitations include the capillary and boiling limits. Different types of heat pipes are described along with considerations for choosing materials and designing heat pipes for specific applications like electronics cooling.
This document discusses the overall heat transfer coefficient (U-value), which measures the ability of multiple conductive and convective barriers to transfer heat. It is influenced by the thickness and conductivity of materials transferring heat. The document provides an equation relating heat transfer rate, surface area, and U-value. It lists common convective heat transfer coefficients for fluids like water and steam. Finally, it calculates the U-value for a single plate heat exchanger using different wall materials like polypropylene, steel, and aluminum.
Heat exchangers transfer heat between two or more fluids that are at different temperatures. They work by bringing the fluids into thermal contact through a conducting surface while preventing mixing. There are several types of heat exchangers classified by their heat exchange process, fluid flow direction, mechanical design, and physical state. A common type is the shell and tube heat exchanger, which consists of a shell with a bundle of tubes inside. One fluid flows through the tubes while another flows over the tubes to transfer heat between the fluids. Double pipe heat exchangers are a simpler design with one pipe inside a larger pipe, allowing fluids to flow within and between the pipes.
1) Heat exchangers are devices that transfer thermal energy between two or more fluids without mixing the fluids. They are commonly used in industries like petroleum refining, power plants, and HVAC systems.
2) Heat exchangers can be classified based on fluid flow patterns (parallel, countercurrent, crossflow) and heat transfer methods. Countercurrent flow is the most efficient as it produces the highest temperature changes in each fluid.
3) Common types of heat exchangers include tubular (shell and tube, concentric tube), plate (flat plate, spiral plate), and extended surface heat exchangers. Tubular heat exchangers involve one fluid flowing inside tubes while another flows
This document provides an introduction to heat transfer and thermodynamics concepts. It discusses how heat transfer is related to thermodynamics and distinguishes between different forms of energy. The three main modes of heat transfer are conduction, convection and radiation. Heat is defined as the transfer of energy between two systems due to a temperature difference, and will flow from the higher temperature object to the lower temperature one. The document provides objectives and outlines concepts like thermal energy, mechanisms of heat transfer, Fourier's law of conduction and applications of heat transfer.
1. The document discusses vapor compression refrigeration systems (VCRS), which are the most commonly used refrigeration systems. In VCRS, the refrigerant undergoes phase change and the refrigeration effect occurs during evaporation.
2. VCRS have higher efficiency and smaller size than air refrigeration systems for a given capacity, but have higher initial costs and issues with refrigerant leakage.
3. The standard VCRS cycle introduces irreversibilities from isenthalpic expansion and non-isothermal heat rejection, lowering its COP compared to the ideal Carnot cycle. Subcooling and superheating can improve the cycle efficiency.
Heat exchangers transfer heat from one fluid to another without direct contact between the fluids. The most common type is the shell-and-tube heat exchanger, which consists of tubes in a shell container. Fluids flow inside the tubes and outside in the shell. Other key types include double-pipe exchangers, plate-and-frame exchangers, air-cooled exchangers, and spiral exchangers. Spiral exchangers have two fluids spiraling in opposite directions to enhance heat transfer.
This document provides an overview of heat pipes and their applications in electronics cooling. It discusses the basic components and operation of heat pipes including the evaporator, condenser, wick and working fluid. The key advantages of heat pipes are their high thermal conductivity and ability to transport heat efficiently. Limitations include the capillary and boiling limits. Different types of heat pipes are described along with considerations for choosing materials and designing heat pipes for specific applications like electronics cooling.
This document discusses the overall heat transfer coefficient (U-value), which measures the ability of multiple conductive and convective barriers to transfer heat. It is influenced by the thickness and conductivity of materials transferring heat. The document provides an equation relating heat transfer rate, surface area, and U-value. It lists common convective heat transfer coefficients for fluids like water and steam. Finally, it calculates the U-value for a single plate heat exchanger using different wall materials like polypropylene, steel, and aluminum.
Heat exchangers transfer heat between two or more fluids that are at different temperatures. They work by bringing the fluids into thermal contact through a conducting surface while preventing mixing. There are several types of heat exchangers classified by their heat exchange process, fluid flow direction, mechanical design, and physical state. A common type is the shell and tube heat exchanger, which consists of a shell with a bundle of tubes inside. One fluid flows through the tubes while another flows over the tubes to transfer heat between the fluids. Double pipe heat exchangers are a simpler design with one pipe inside a larger pipe, allowing fluids to flow within and between the pipes.
This document provides an overview of topics related to heat and mass transfer, including:
- Fins and their applications (Unit I)
- Convection boundary layer concepts including velocity and thermal boundary layers (Unit II)
- Heat exchangers including concentric tube, cross flow, and shell and tube designs (Unit III)
- Boiling and condensation processes including boiling curves and regimes (Unit IV)
- Mass transfer concepts and analogies to heat transfer including diffusion, convection, and concentration boundary layers (Unit V)
It defines key terms and concepts for each topic and provides illustrations of processes like boundary layer development, boiling curves, and mass transfer mechanisms like diffusion and convection.
This document provides an overview of the functional design of two types of heat exchangers: shell and tube heat exchangers and plate heat exchangers. It discusses the key components, design considerations, and step-by-step design procedures for shell and tube heat exchangers. These include determining the heat transfer area, number of tubes, tube dimensions, baffle design, and accounting for pressure drops and fouling factors. It also introduces plate heat exchangers and discusses their mechanical characteristics and design methods at a high level.
The document provides an overview of basic HVAC systems. It defines HVAC as heating, ventilation, and air conditioning. It describes the major components of HVAC systems including compressors, condensers, expansion valves, and evaporators. It explains that HVAC systems work using a vapor compression refrigeration cycle consisting of these four components. The document also discusses different types of HVAC systems like split, central, and packaged AC systems. It provides diagrams of typical system designs and components.
This document provides an overview of HVAC (heating, ventilation, and air conditioning) systems. It defines HVAC as the control of air temperature, moisture content, and proper air movement to maintain acceptable air quality. It then describes common HVAC applications in buildings and industries. The document outlines the basic components and operating cycle of air conditioning systems. It also discusses factors to consider when selecting and designing HVAC systems, such as cooling load calculations, equipment types, ducting, and air distribution. Finally, it covers recent trends toward more energy efficient HVAC equipment and controls.
This file contains slides on Steady State Heat Conduction in Multiple Dimensions.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: 2-D conduction - Various methods of solution – Analytical - Graphical - Analogical – Numerical – Shape factors for 2-D conduction - Problems
boiler accessories, basics of economizer, types of economizer, air preheater, types of air preheater, reheater, basics of superheater, types of superheater.
This file contains slides on One-dimensional, steady state heat conduction without heat generation. The slides were prepared while teaching Heat Transfer course to the M.Tech. students.
Topics covered: Plane slab - composite slabs – contact resistance – cylindrical Systems – composite cylinders - spherical systems – composite spheres - critical thickness of insulation – optimum thickness – systems with variable thermal conductivity
Components of Vapor Compression Refrigeration SystemMahmudul Hasan
This document discusses the key components of a vapor compression refrigeration system:
1) The evaporator where refrigerant absorbs heat and evaporates, cooling the air flowing through it.
2) The compressor which compresses the vapor from the evaporator.
3) The condenser where the high pressure vapor is cooled and condensed to a liquid.
4) The expansion valve which controls the flow of liquid refrigerant into the evaporator.
It also covers types of each component and their functions, as well as the environmental effects of refrigerant emissions.
Thermodynamics deals with energy and its transformation between different forms. The first law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. A thermodynamic system exchanges energy in the form of heat or work with its surroundings. Closed systems exchange only energy, while open systems can exchange both energy and matter. Thermodynamic properties like pressure, temperature, and volume are used to describe different thermodynamic processes that occur at either constant values (isobaric, isochoric, isothermal) or with varying values.
Summary of lmtd and e ntu. The Log Mean Temperature Difference Method (LMTD) The Logarithmic Mean Temperature Difference(LMTD) is valid only for heat exchanger with one shell pass and one tube pass. For multiple number of shell and tube passes the flow pattern in a heat exchanger is neither purely co-current nor purely counter-current. The temperature difference between the hot and cold fluids varies along the heat exchanger. It is convenient to have a mean temperature difference Tm for use in the relation. s mQ UA T
3. The mean temperature difference in a heat transfer process depends on the direction of fluid flows involved in the process. The primary and secondary fluid in an heat exchanger process may flow in the same direction - parallel flow or cocurrent flow in the opposite direction - countercurrent flow or perpendicular to each other - cross flow
This document discusses heat transfer by conduction. It defines conduction as the transfer of heat through a material by molecular interaction and without bulk motion. Fourier's law of heat conduction states that the rate of heat transfer is proportional to the temperature gradient and the area. The document presents the equations for one-dimensional heat conduction through a plane wall and a composite wall made of different materials. It also lists the assumptions of Fourier's law, such as steady-state conditions and homogeneous/isotropic materials.
Heat exchangers transfer heat between two or more fluids. There are three main types: direct transfer, storage, and direct contact. Direct transfer type heat exchangers simultaneously flow hot and cold fluids through a separating wall. Storage type heat exchangers alternately flow hot and cold fluids through a porous matrix. Direct contact type heat exchangers do not separate the fluids. Common examples are plate heat exchangers and shell-and-tube heat exchangers. Design considerations include materials, operating parameters, fouling factors, and determining the required heat transfer area.
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
This document discusses bi-metallic thermometers. It begins with an introduction on the importance of temperature measurement. It then explains that a bi-metallic thermometer uses two metals with different coefficients of thermal expansion bonded together. As temperature changes, the strip bends due to the differential expansion of the metals. This movement is used to indicate the temperature. Key features discussed include the construction of the bi-metallic strip, how temperature causes it to bend, common metal combinations used, and applications in industrial processes and devices.
Here are the key steps to solve this problem:
1) Given: Initial diameter (D1) = 0.5 m
Initial pressure (P1) = 500 kPa
Final diameter (D2) = 0.55 m
2) The pressure is proportional to diameter. So we can write:
P/P1 = (D/D1)n
Where n is the proportionality constant.
3) Since the process is reversible, n = 1 (based on the property of reversible process where PV must be proportional to T).
4) Putting n = 1 in the above equation, we get:
P2/P1 = (D2/D1
Basics of HVAC - Part 1 (Heating Ventilation Air Conditioning)MOHAMMED KHAN
The document provides an overview of the basics of HVAC (heating, ventilation, and air conditioning) systems. It was prepared by Mohammed Abdul Mujeeb Khan, a mechanical engineer. The document defines HVAC, describes common HVAC system types like direct expansion and chilled water systems, and covers topics like temperature and humidity control, load calculation, equipment selection, and system design.
Lectures on Heat Transfer - Introduction - Applications - Fundamentals - Gove...tmuliya
This file contains Introduction to Heat Transfer and Fundamental laws governing heat transfer.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Introduction to transient Heat conduction, Lamped System Analysis, Approxiamate Analytical and graphical method and Numerical method for one and two dimensional heat conduction by using Explicit and Implicit method
This document provides an overview of thermodynamics and heat transfer. It defines key concepts like heat, thermodynamics, and the three modes of heat transfer - conduction, convection, and radiation. Thermodynamics deals with the amount of heat transfer between equilibrium states, while heat transfer determines the rates of energy transfer and temperature variations. Heat is always transferred from higher to lower temperatures until equilibrium is reached. The document also discusses other forms of energy, internal energy, and the first law of thermodynamics. It provides details on each heat transfer mechanism and examples of situations that can involve multiple mechanisms simultaneously.
Heat & Mass Transfer Chap 1 (FE-509) Food Engineering UAFAown Rizvi
This chapter introduces key concepts of heat transfer and thermodynamics. It defines heat transfer as energy transferred due to a temperature difference and discusses the three mechanisms of heat transfer: conduction, convection, and radiation. Conduction involves energy transfer through direct contact of particles. Convection combines conduction and bulk fluid motion. Radiation transfers energy via electromagnetic waves. The chapter establishes relationships like Fourier's law of conduction and Newton's law of cooling and introduces concepts such as thermal conductivity and heat transfer coefficients.
This document provides an overview of topics related to heat and mass transfer, including:
- Fins and their applications (Unit I)
- Convection boundary layer concepts including velocity and thermal boundary layers (Unit II)
- Heat exchangers including concentric tube, cross flow, and shell and tube designs (Unit III)
- Boiling and condensation processes including boiling curves and regimes (Unit IV)
- Mass transfer concepts and analogies to heat transfer including diffusion, convection, and concentration boundary layers (Unit V)
It defines key terms and concepts for each topic and provides illustrations of processes like boundary layer development, boiling curves, and mass transfer mechanisms like diffusion and convection.
This document provides an overview of the functional design of two types of heat exchangers: shell and tube heat exchangers and plate heat exchangers. It discusses the key components, design considerations, and step-by-step design procedures for shell and tube heat exchangers. These include determining the heat transfer area, number of tubes, tube dimensions, baffle design, and accounting for pressure drops and fouling factors. It also introduces plate heat exchangers and discusses their mechanical characteristics and design methods at a high level.
The document provides an overview of basic HVAC systems. It defines HVAC as heating, ventilation, and air conditioning. It describes the major components of HVAC systems including compressors, condensers, expansion valves, and evaporators. It explains that HVAC systems work using a vapor compression refrigeration cycle consisting of these four components. The document also discusses different types of HVAC systems like split, central, and packaged AC systems. It provides diagrams of typical system designs and components.
This document provides an overview of HVAC (heating, ventilation, and air conditioning) systems. It defines HVAC as the control of air temperature, moisture content, and proper air movement to maintain acceptable air quality. It then describes common HVAC applications in buildings and industries. The document outlines the basic components and operating cycle of air conditioning systems. It also discusses factors to consider when selecting and designing HVAC systems, such as cooling load calculations, equipment types, ducting, and air distribution. Finally, it covers recent trends toward more energy efficient HVAC equipment and controls.
This file contains slides on Steady State Heat Conduction in Multiple Dimensions.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India, during Sept. – Dec. 2010.
Contents: 2-D conduction - Various methods of solution – Analytical - Graphical - Analogical – Numerical – Shape factors for 2-D conduction - Problems
boiler accessories, basics of economizer, types of economizer, air preheater, types of air preheater, reheater, basics of superheater, types of superheater.
This file contains slides on One-dimensional, steady state heat conduction without heat generation. The slides were prepared while teaching Heat Transfer course to the M.Tech. students.
Topics covered: Plane slab - composite slabs – contact resistance – cylindrical Systems – composite cylinders - spherical systems – composite spheres - critical thickness of insulation – optimum thickness – systems with variable thermal conductivity
Components of Vapor Compression Refrigeration SystemMahmudul Hasan
This document discusses the key components of a vapor compression refrigeration system:
1) The evaporator where refrigerant absorbs heat and evaporates, cooling the air flowing through it.
2) The compressor which compresses the vapor from the evaporator.
3) The condenser where the high pressure vapor is cooled and condensed to a liquid.
4) The expansion valve which controls the flow of liquid refrigerant into the evaporator.
It also covers types of each component and their functions, as well as the environmental effects of refrigerant emissions.
Thermodynamics deals with energy and its transformation between different forms. The first law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. A thermodynamic system exchanges energy in the form of heat or work with its surroundings. Closed systems exchange only energy, while open systems can exchange both energy and matter. Thermodynamic properties like pressure, temperature, and volume are used to describe different thermodynamic processes that occur at either constant values (isobaric, isochoric, isothermal) or with varying values.
Summary of lmtd and e ntu. The Log Mean Temperature Difference Method (LMTD) The Logarithmic Mean Temperature Difference(LMTD) is valid only for heat exchanger with one shell pass and one tube pass. For multiple number of shell and tube passes the flow pattern in a heat exchanger is neither purely co-current nor purely counter-current. The temperature difference between the hot and cold fluids varies along the heat exchanger. It is convenient to have a mean temperature difference Tm for use in the relation. s mQ UA T
3. The mean temperature difference in a heat transfer process depends on the direction of fluid flows involved in the process. The primary and secondary fluid in an heat exchanger process may flow in the same direction - parallel flow or cocurrent flow in the opposite direction - countercurrent flow or perpendicular to each other - cross flow
This document discusses heat transfer by conduction. It defines conduction as the transfer of heat through a material by molecular interaction and without bulk motion. Fourier's law of heat conduction states that the rate of heat transfer is proportional to the temperature gradient and the area. The document presents the equations for one-dimensional heat conduction through a plane wall and a composite wall made of different materials. It also lists the assumptions of Fourier's law, such as steady-state conditions and homogeneous/isotropic materials.
Heat exchangers transfer heat between two or more fluids. There are three main types: direct transfer, storage, and direct contact. Direct transfer type heat exchangers simultaneously flow hot and cold fluids through a separating wall. Storage type heat exchangers alternately flow hot and cold fluids through a porous matrix. Direct contact type heat exchangers do not separate the fluids. Common examples are plate heat exchangers and shell-and-tube heat exchangers. Design considerations include materials, operating parameters, fouling factors, and determining the required heat transfer area.
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
This document discusses bi-metallic thermometers. It begins with an introduction on the importance of temperature measurement. It then explains that a bi-metallic thermometer uses two metals with different coefficients of thermal expansion bonded together. As temperature changes, the strip bends due to the differential expansion of the metals. This movement is used to indicate the temperature. Key features discussed include the construction of the bi-metallic strip, how temperature causes it to bend, common metal combinations used, and applications in industrial processes and devices.
Here are the key steps to solve this problem:
1) Given: Initial diameter (D1) = 0.5 m
Initial pressure (P1) = 500 kPa
Final diameter (D2) = 0.55 m
2) The pressure is proportional to diameter. So we can write:
P/P1 = (D/D1)n
Where n is the proportionality constant.
3) Since the process is reversible, n = 1 (based on the property of reversible process where PV must be proportional to T).
4) Putting n = 1 in the above equation, we get:
P2/P1 = (D2/D1
Basics of HVAC - Part 1 (Heating Ventilation Air Conditioning)MOHAMMED KHAN
The document provides an overview of the basics of HVAC (heating, ventilation, and air conditioning) systems. It was prepared by Mohammed Abdul Mujeeb Khan, a mechanical engineer. The document defines HVAC, describes common HVAC system types like direct expansion and chilled water systems, and covers topics like temperature and humidity control, load calculation, equipment selection, and system design.
Lectures on Heat Transfer - Introduction - Applications - Fundamentals - Gove...tmuliya
This file contains Introduction to Heat Transfer and Fundamental laws governing heat transfer.
The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Introduction to transient Heat conduction, Lamped System Analysis, Approxiamate Analytical and graphical method and Numerical method for one and two dimensional heat conduction by using Explicit and Implicit method
This document provides an overview of thermodynamics and heat transfer. It defines key concepts like heat, thermodynamics, and the three modes of heat transfer - conduction, convection, and radiation. Thermodynamics deals with the amount of heat transfer between equilibrium states, while heat transfer determines the rates of energy transfer and temperature variations. Heat is always transferred from higher to lower temperatures until equilibrium is reached. The document also discusses other forms of energy, internal energy, and the first law of thermodynamics. It provides details on each heat transfer mechanism and examples of situations that can involve multiple mechanisms simultaneously.
Heat & Mass Transfer Chap 1 (FE-509) Food Engineering UAFAown Rizvi
This chapter introduces key concepts of heat transfer and thermodynamics. It defines heat transfer as energy transferred due to a temperature difference and discusses the three mechanisms of heat transfer: conduction, convection, and radiation. Conduction involves energy transfer through direct contact of particles. Convection combines conduction and bulk fluid motion. Radiation transfers energy via electromagnetic waves. The chapter establishes relationships like Fourier's law of conduction and Newton's law of cooling and introduces concepts such as thermal conductivity and heat transfer coefficients.
This document discusses heat transfer and provides objectives and an overview of key concepts. It begins by defining heat transfer and its relationship to thermodynamics. It then outlines the main objectives, which are to understand the basic heat transfer mechanisms of conduction, convection, and radiation. It also discusses how heat transfer problems are used in engineering applications and provides background on the historical development of theories around heat and thermal energy.
This document provides an introduction and overview of key concepts in heat and mass transfer. It defines heat transfer and distinguishes it from thermodynamics. The three main modes of heat transfer are described: conduction, convection, and radiation. Fourier's law of heat conduction, Newton's law of cooling, and the Stefan-Boltzmann law of radiation are also introduced. The document outlines the relationship between heat transfer and thermodynamics, and how heat transfer problems are approached in engineering.
This document provides an introduction and overview of key concepts in heat and mass transfer. It defines heat transfer and distinguishes it from thermodynamics. The three main modes of heat transfer are described as conduction, convection and radiation. Fourier's law of heat conduction, Newton's law of cooling and the Stefan-Boltzmann law of radiation are introduced. The document also discusses applications of heat transfer, the historical development of understanding heat, and modeling approaches in engineering heat transfer problems.
This document provides an introduction to heat transfer and thermodynamics concepts. It discusses how heat transfer, thermodynamics, and various energy concepts are related. The three main modes of heat transfer - conduction, convection and radiation - are introduced, along with the governing equations for each. Fourier's law of heat conduction, Newton's law of cooling, and the Stefan-Boltzmann law of radiation are outlined. The document also discusses combined heat transfer mechanisms, thermal properties, and applications of heat transfer concepts.
1) The document discusses the key concepts and objectives of conduction heat transfer including understanding the basic mechanisms of heat transfer such as conduction, convection, and radiation.
2) It explains the differences between thermodynamics, which deals with the amount of heat transfer between equilibrium states, and heat transfer which determines the rates of energy transfers.
3) The three modes of heat transfer - conduction, convection and radiation - are defined and the governing equations for each are provided including Fourier's law of conduction, Newton's law of cooling, and Stefan-Boltzmann law of radiation.
This document provides an overview of fundamentals of heat transfer. It discusses key objectives like understanding the relationship between thermodynamics and heat transfer. The main modes of heat transfer - conduction, convection and radiation - are introduced. Conduction involves energy transfer through direct contact of particles. Convection requires fluid motion, while radiation occurs via electromagnetic waves. Concepts like Fourier's law of conduction and Newton's law of cooling are also summarized.
This document provides an outline for an ME-412 Heat and Mass Transfer course. The course will cover topics including conduction, convection, radiation, heat exchangers, and mass transfer. Recommended textbooks are listed. Prerequisites for the course are ME 212: Thermodynamics-II and ME 213: Fluid Mechanics-II. The instructor is Dr. Adnan Qamar Tareen from the Mechanical Engineering Department.
This chapter introduces the concepts of thermodynamics and heat transfer. Thermodynamics deals with equilibrium states while heat transfer involves systems lacking thermal equilibrium. The three modes of heat transfer are conduction, convection, and radiation. Conduction involves the transfer of energy between adjacent particles in direct contact. Convection involves the combined mechanisms of conduction and fluid motion. Radiation transfers energy via electromagnetic waves without a medium. Fourier's law, Newton's law of cooling, and the Stefan-Boltzmann law govern conduction, convection, and radiation respectively. Example problems demonstrate applying conservation of energy to analyze various heat transfer processes.
This document provides an introduction to heat transfer and thermodynamics concepts. It discusses how thermodynamics deals with the amount of heat transfer between systems, while heat transfer determines the rates of energy transfer. Heat can be transferred via three modes: conduction, convection, and radiation. Conduction involves energy transfer between adjacent particles through collisions. Convection combines conduction and fluid motion. Radiation involves electromagnetic wave emission from hot objects. Laws like Fourier's law, Newton's law of cooling, and Stefan-Boltzmann law govern these transfer modes.
Thermodynamics deals with the amount of heat transfer between systems, while heat transfer determines the rates of energy transfer and temperature variations. Heat is transferred between objects by conduction, convection, or radiation. Conduction involves the transfer of kinetic energy between particles in direct contact. Convection combines conduction and fluid motion to transfer heat. Radiation emits electromagnetic waves and does not require a medium. Engineering applications include determining heat transfer rates and sizes of heat exchange equipment based on temperature differences and properties of materials.
The document provides an overview of key concepts in heat transfer, including:
1) It defines heat transfer and the three main modes of heat transfer: conduction, convection, and radiation.
2) It explains the relationship between heat transfer and thermodynamics, noting that heat transfer studies the rate and distribution of temperature over time.
3) It provides definitions and examples of key terms used in heat transfer problems, such as steady state, control mass/volume, and uncertainty.
The phrase “heat transfer” refers to the distribution and changes in temperature that result from the transport of heat (thermal energy) induced by temperature differences. The study of transport phenomena focuses on the interchange of momentum, energy, and mass through conduction, convection, and radiation.
Mass and heat transfer deals with the determination of rates of energy transfer between systems and variations in temperature. There are three main modes of heat transfer: conduction, convection, and radiation. Conduction involves the transfer of energy between adjacent particles through interactions. Convection refers to the combined effects of conduction and bulk fluid motion. Radiation involves the emission and transmission of electromagnetic waves and can occur through a vacuum.
Conduction, convection, and radiation are the three modes of heat transfer. Conduction involves the transfer of kinetic energy between adjacent particles in a medium through direct contact. Convection involves the transfer of heat by the circulation of fluids such as gases and liquids. Radiation involves the emission and transmission of electromagnetic waves, which can travel through vacuum and do not require a medium.
Samir Uddin's document summarizes various modes of heat transfer. It defines heat and discusses the difference between heat transfer and thermodynamics. The three main modes of heat transfer are conduction, convection, and radiation. Conduction involves the transfer of heat between objects in direct contact. Convection refers to heat transfer between a solid and adjacent moving fluid. Radiation involves the transfer of heat through electromagnetic waves without a medium. The document also outlines Fourier's Law of heat conduction and Newton's Law of Cooling.
This chapter introduces the concepts of thermodynamics and heat transfer. Thermodynamics deals with equilibrium states while heat transfer is a non-equilibrium phenomenon that depends on temperature differences. The three modes of heat transfer are conduction, convection, and radiation. Conduction involves the transfer of energy between particles through interactions. Convection involves the transfer of energy by fluid motion. Radiation emits electromagnetic waves from matter due to temperature. Fourier's law, Newton's law of cooling, and the Stefan-Boltzmann law govern conduction, convection, and radiation respectively.
Thermodynamics is the branch of physics that deals with heat and other forms of energy. The first law of thermodynamics states that the total energy of a system remains constant, such that any increase in one form of energy (such as heat) results in an equal decrease in another form (such as work). The second law states that heat cannot spontaneously flow from a colder body to a hotter body without an input of work. The third law states that the entropy of a perfect crystal approaches zero as the temperature approaches absolute zero.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
2. 2
Objectives
• Understand how thermodynamics and heat transfer are related
to each other
• Distinguish thermal energy from other forms of energy, and heat
transfer from other forms of energy transfer
• Perform general energy balances as well as surface energy
balances
• Understand the basic mechanisms of heat transfer, which are
conduction, convection, and radiation, and Fourier's law of heat
conduction, Newton's law of cooling, and the Stefan–Boltzmann
law of radiation
• Identify the mechanisms of heat transfer that occur
simultaneously in practice
• Develop an awareness of the cost associated with heat losses
• Solve various heat transfer problems encountered in practice
3. 3
THERMODYNAMICS AND HEAT TRANSFER
• Heat: The form of energy that can be transferred from one
system to another as a result of temperature difference.
• Thermodynamics is concerned with the amount of heat
transfer as a system undergoes a process from one
equilibrium state to another.
• Heat Transfer deals with the determination of the rates of
such energy transfers as well as variation of temperature.
• The transfer of energy as heat is always from the higher-
temperature medium to the lower-temperature one.
• Heat transfer stops when the two mediums reach the same
temperature.
• Heat can be transferred in three different modes:
conduction, convection, radiation
6. 6
Historical Background Kinetic theory: Treats molecules as
tiny balls that are in motion and thus
possess kinetic energy.
Heat: The energy associated with the
random motion of atoms and
molecules.
Caloric theory: Heat is a fluidlike
substance called the caloric that is a
massless, colorless, odorless, and
tasteless substance that can be
poured from one body into another
It was only in the middle of the
nineteenth century that we had a true
physical understanding of the nature of
heat.
Careful experiments of the Englishman
James P. Joule published in 1843
convinced the skeptics that heat was
not a substance after all, and thus put
the caloric theory to rest.
8. 8
ENGINEERING HEAT TRANSFER
Heat transfer equipment such as heat exchangers, boilers, condensers, radiators,
heaters, furnaces, refrigerators, and solar collectors are designed primarily on the
basis of heat transfer analysis.
The heat transfer problems encountered in practice can be considered in two groups:
(1) rating and (2) sizing problems.
The rating problems deal with the determination of the heat transfer rate for an
existing system at a specified temperature difference.
The sizing problems deal with the determination of the size of a system in order to
transfer heat at a specified rate for a specified temperature difference.
An engineering device or process can be studied either experimentally (testing and
taking measurements) or analytically (by analysis or calculations).
The experimental approach has the advantage that we deal with the actual physical
system, and the desired quantity is determined by measurement, within the limits of
experimental error. However, this approach is expensive, timeconsuming, and often
impractical.
The analytical approach (including the numerical approach) has the advantage that it
is fast and inexpensive, but the results obtained are subject to the accuracy of the
assumptions, approximations, and idealizations made in the analysis.
10. 10
Energy can exist in numerous forms such as:
◦ thermal,
◦ mechanical,
◦ kinetic,
◦ potential,
◦ electrical,
◦ magnetic,
◦ chemical,
◦ nuclear.
Their sum constitutes the total energy E (or e on a
unit mass basis) of a system.
The sum of all microscopic forms of energy is called the
internal energy of a system.
HEAT AND OTHER FORMS OF ENERGY
11. 11
Internal energy: May be viewed as the sum of the kinetic and
potential energies of the molecules.
Sensible heat: The kinetic energy of the molecules.
Latent heat: The internal energy associated with the phase of a
system.
Chemical (bond) energy: The internal energy associated with
the atomic bonds in a molecule.
Nuclear energy: The internal energy associated with the
bonds within the nucleus of the atom itself.
What is thermal energy?
What is the difference between thermal
energy and heat?
12. 12
In the analysis of systems
that involve fluid flow, we
frequently encounter the
combination of properties u
and Pv.
The combination is defined
as enthalpy (h = u + Pv).
The term Pv represents the
flow energy of the fluid (also
called the flow work).
13. 13
Specific heat: The energy required to
raise the temperature of a unit mass of a
substance by one degree.
Two kinds of specific heats:
◦ specific heat at constant volume cv
◦ specific heat at constant pressure cp
The specific heats of a substance, in
general, depend on two independent
properties such as temperature and
pressure.
At low pressures all real gases approach
ideal gas behavior, and therefore their
specific heats depend on temperature
only.
14. 14
Incompressible substance: A
substance whose specific volume (or
density) does not change with
temperature or pressure.
The constant-volume and constant-
pressure specific heats are identical
for incompressible substances.
The specific heats of incompressible
substances depend on temperature
only.
15. 15
Energy can be transferred to or from a given
mass by two mechanisms:
heat transfer and work.
Heat transfer rate: The amount of heat
transferred per unit time.
Heat flux: The rate of heat transfer per unit
area normal to the direction of heat transfer.
when is constant:
Power: The work
done per unit time.
16. 16
The energy balance for any
system undergoing any process
in the rate form
The first law of thermodynamics (conservation of energy
principle) states that energy can neither be created nor destroyed
during a process; it can only change forms.
The net change (increase or
decrease) in the total energy of
the system during a process is
equal to the difference between
the total energy entering and the
total energy leaving the system
during that process.
17. 17
In heat transfer problems it is convenient to
write a heat balance and to treat the
conversion of nuclear, chemical,
mechanical, and electrical energies into
thermal energy as heat generation.
18. 18
Energy Balance for Closed Systems (Fixed Mass)
A closed system consists of a fixed mass.
The total energy E for most systems
encountered in practice consists of the
internal energy U.
This is especially the case for stationary
systems since they don’t involve any
changes in their velocity or elevation during
a process.
19. 19
Energy Balance for
Steady-Flow Systems
A large number of engineering devices such as
water heaters and car radiators involve mass flow
in and out of a system, and are modeled as
control volumes.
Most control volumes are analyzed under steady
operating conditions.
The term steady means no change with time at a
specified location.
Mass flow rate: The amount of mass flowing
through a cross section of a flow device per unit
time.
Volume flow rate: The volume of a fluid flowing
through a pipe or duct per unit time.
20. 20
Surface Energy Balance
This relation is valid for both steady and
transient conditions, and the surface
energy balance does not involve heat
generation since a surface does not
have a volume.
A surface contains no volume or mass,
and thus no energy. Thereore, a surface
can be viewed as a fictitious system
whose energy content remains constant
during a process.
21. 21
Heat as the form of energy that can be transferred from one system to
another as a result of temperature difference.
A thermodynamic analysis is concerned with the amount of heat
transfer as a system undergoes a process from one equilibrium state to
another.
The science that deals with the determination of the rates of such
energy transfers is the heat transfer.
The transfer of energy as heat is always from the higher-temperature
medium to the lower-temperature one, and heat transfer stops when
the two mediums reach the same temperature.
Heat can be transferred in three basic modes:
◦ conduction
◦ convection
◦ radiation
All modes of heat transfer require the existence of a temperature
difference.
22. 22
Heat conduction
through a large plane
wall of thickness ∆x
and area A.
CONDUCTION
Conduction: The transfer of energy from the more
energetic particles of a substance to the adjacent less
energetic ones as a result of interactions between the
particles.
In gases and liquids, conduction is due to the
collisions and diffusion of the molecules during their
random motion.
In solids, it is due to the combination of vibrations of
the molecules in a lattice and the energy transport by
free electrons.
The rate of heat conduction through a plane layer is
proportional to the temperature difference across the
layer and the heat transfer area, but is inversely
proportional to the thickness of the layer.
23. 23
When x → 0 Fourier’s law of
heat conduction
Thermal conductivity, k: A measure of the ability
of a material to conduct heat.
Temperature gradient dT/dx: The slope of the
temperature curve on a T-x diagram.
Heat is conducted in the direction of decreasing
temperature, and the temperature gradient becomes
negative when temperature decreases with
increasing x. The negative sign in the equation
ensures that heat transfer in the positive x direction
is a positive quantity.
The rate of heat conduction
through a solid is directly
proportional to its thermal
conductivity.
In heat conduction
analysis, A represents
the area normal to the
direction of heat
transfer.
25. 25
Thermal
Conductivity
Thermal conductivity:
The rate of heat transfer
through a unit thickness
of the material per unit
area per unit
temperature difference.
The thermal conductivity
of a material is a
measure of the ability of
the material to conduct
heat.
A high value for thermal
conductivity indicates
that the material is a
good heat conductor,
and a low value indicates
that the material is a
poor heat conductor or
insulator.
A simple experimental setup
to determine the thermal
conductivity of a material.
27. 27
The mechanisms of heat
conduction in different
phases of a substance.
The thermal conductivities of gases such
as air vary by a factor of 104
from those of
pure metals such as copper.
Pure crystals and metals have the highest
thermal conductivities, and gases and
insulating materials the lowest.
28. 28
The variation of
the thermal
conductivity of
various solids,
liquids, and gases
with temperature.
29. 29
Thermal Diffusivity
cp Specific heat, J/kg · °C: Heat capacity
per unit mass
ρcp Heat capacity, J/m3
·°C: Heat capacity
per unit volume
α Thermal diffusivity, m2
/s: Represents
how fast heat diffuses through a material
A material that has a high thermal
conductivity or a low heat capacity will
obviously have a large thermal diffusivity.
The larger the thermal diffusivity, the faster
the propagation of heat into the medium.
A small value of thermal diffusivity means
that heat is mostly absorbed by the
material and a small amount of heat is
conducted further.
30. 30
CONVECTION
Convection: The mode of
energy transfer between a
solid surface and the
adjacent liquid or gas that is
in motion, and it involves
the combined effects of
conduction and fluid motion.
The faster the fluid motion,
the greater the convection
heat transfer.
In the absence of any bulk
fluid motion, heat transfer
between a solid surface and
the adjacent fluid is by pure
conduction.
Heat transfer from a hot surface to air
by convection.
31. 31
Forced convection: If
the fluid is forced to flow
over the surface by
external means such as
a fan, pump, or the wind.
Natural (or free)
convection: If the fluid
motion is caused by
buoyancy forces that are
induced by density
differences due to the
variation of temperature
in the fluid.
The cooling of a boiled egg by
forced and natural convection.
Heat transfer processes that involve change of phase of a fluid are also
considered to be convection because of the fluid motion induced during
the process, such as the rise of the vapor bubbles during boiling or the
fall of the liquid droplets during condensation.
32. 32
Newton’s law of cooling
h convection heat transfer coefficient, W/m2
· °C
As the surface area through which convection heat transfer takes place
Ts the surface temperature
T∞ the temperature of the fluid sufficiently far from the surface.
The convection heat transfer
coefficient h is not a
property of the fluid.
It is an experimentally
determined parameter
whose value depends on all
the variables influencing
convection such as
- the surface geometry
- the nature of fluid motion
- the properties of the fluid
- the bulk fluid velocity
34. 34
RADIATION
• Radiation: The energy emitted by matter in the form of electromagnetic
waves (or photons) as a result of the changes in the electronic
configurations of the atoms or molecules.
• Unlike conduction and convection, the transfer of heat by radiation does
not require the presence of an intervening medium.
• In fact, heat transfer by radiation is fastest (at the speed of light) and it
suffers no attenuation in a vacuum. This is how the energy of the sun
reaches the earth.
• In heat transfer studies we are interested in thermal radiation, which is
the form of radiation emitted by bodies because of their temperature.
• All bodies at a temperature above absolute zero emit thermal radiation.
• Radiation is a volumetric phenomenon, and all solids, liquids, and
gases emit, absorb, or transmit radiation to varying degrees.
• However, radiation is usually considered to be a surface phenomenon
for solids.
35. 35
Stefan–Boltzmann law
σ = 5.670 × 10−8
W/m2
· K4
Stefan–Boltzmann constant
Blackbody: The idealized surface that emits radiation at the maximum rate.
Blackbody radiation represents the maximum
amount of radiation that can be emitted from
a surface at a specified temperature.
Emissivity ε : A measure of how closely
a surface approximates a blackbody for
which ε = 1 of the surface. 0≤ ε ≤ 1.
Radiation emitted
by real surfaces
36. 36
Absorptivity α: The fraction of the radiation energy incident on a
surface that is absorbed by the surface. 0≤ α ≤ 1
A blackbody absorbs the entire radiation incident on it (α = 1).
Kirchhoff’s law: The emissivity and the absorptivity of a surface at
a given temperature and wavelength are equal.
The absorption of radiation incident on
an opaque surface of absorptivity .
37. 37
Radiation heat transfer between a surface
and the surfaces surrounding it.
Net radiation heat transfer:
The difference between the
rates of radiation emitted by the
surface and the radiation
absorbed.
The determination of the net
rate of heat transfer by radiation
between two surfaces is a
complicated matter since it
depends on
• the properties of the surfaces
• their orientation relative to
each other
• the interaction of the medium
between the surfaces with
radiation
Radiation is usually
significant relative to
conduction or natural
convection, but
negligible relative to
forced convection.
When a surface is completely enclosed by a
much larger (or black) surface at temperature
Tsurr separated by a gas (such as air) that
does not intervene with radiation, the net rate
of radiation heat transfer between these
two surfaces is given by
38. 38
Combined heat transfer coefficient hcombined
Includes the effects of both convection and radiation
When radiation and convection occur
simultaneously between a surface and a gas:
39. 39
SIMULTANEOUS HEAT
TRANSFER MECHANISMS
Although there are three mechanisms
of heat transfer, a medium may involve
only two of them simultaneously.
Heat transfer is only by conduction in opaque solids,
but by conduction and radiation in semitransparent
solids.
A solid may involve conduction and radiation but not
convection. A solid may involve convection and/or
radiation on its surfaces exposed to a fluid or other
surfaces.
Heat transfer is by conduction and possibly by
radiation in a still fluid (no bulk fluid motion) and by
convection and radiation in a flowing fluid.
In the absence of radiation, heat transfer through a
fluid is either by conduction or convection, depending
on the presence of any bulk fluid motion.
Convection = Conduction + Fluid motion
Heat transfer through a vacuum is by radiation.
Most gases between two solid surfaces
do not interfere with radiation.
Liquids are usually strong absorbers of
radiation.
43. 43
EES (Engineering Equation Solver)
(Pronounced as ease): EES is a program that
solves systems of linear or nonlinear
algebraic or differential equations
numerically. It has a large library of built-in
thermodynamic property functions as well as
mathematical functions. Unlike some
software packages, EES does not solve
engineering problems; it only solves the
equations supplied by the user.
Engineering Software Packages
Thinking that a person who can use the
engineering software packages without
proper training on fundamentals can
practice engineering is like thinking that a
person who can use a wrench can work as
a car mechanic.
44. 44
A Remark on Significant Digits
In engineering calculations, the
information given is not known to
more than a certain number of
significant digits, usually three
digits.
Consequently, the results
obtained cannot possibly be
accurate to more significant
digits.
Reporting results in more
significant digits implies greater
accuracy than exists, and it
should be avoided.
A result with more significant
digits than that of given data
falsely implies more accuracy.
45. Thermodynamics and Heat Transfer
◦ Application areas of heat transfer
◦ Historical background
Engineering Heat Transfer
◦ Modeling in engineering
Heat and Other Forms of Energy
◦ Specific heats of gases, liquids, and solids
◦ Energy transfer
The First Law of Thermodynamics
◦ Energy balance for closed systems (Fixed Mass)
◦ Energy balance for steady-flow systems
◦ Surface energy balance
45