- Work and heat transfer are the two modes of energy interaction between a system and its surroundings. These interactions bring about changes in the system's properties.
- Work transfer is a path-dependent process that occurs due to displacement of the system boundary or through other means like stirring work, flow work, or shaft work. Heat transfer is also path-dependent and occurs due to temperature differences between the system and surroundings.
- Both work and heat transfer can be calculated using integration methods if the process path is known, and they are considered path functions. Heat transfer depends on the temperature change in the system, while work transfer depends on boundary displacement or other mechanisms.
1) The document discusses heat, work, and the first law of thermodynamics. It defines heat and work as the two types of energy transfer across boundaries of closed systems.
2) The first law of thermodynamics, also called the law of conservation of energy, states that the total energy of a system remains constant, with increases in internal energy equal to net heat and work transfers.
3) Specific examples are provided to illustrate the first law for closed systems undergoing various processes like heating, cooling, and adiabatic changes with and without work. Formulas are derived for calculating internal energy changes based on the first law.
1) This document discusses heat, work, and the first law of thermodynamics. It defines heat and work as the two ways energy can transfer across the boundary of a closed system, with heat transferring due to a temperature difference and work occurring from a force acting through a distance.
2) The first law of thermodynamics states that the change in a system's internal energy is equal to the net heat transferred to the system plus the net work done by the system. This is illustrated with examples of processes involving only heat transfer, where the energy change equals the net heat.
3) Different types of thermodynamic processes are examined, including isobaric, isochoric, isothermal, and poly
This chapter discusses work and heat transfer in thermodynamic systems. It defines work as force times distance for simple mechanical systems, and as the potential to lift a mass for thermodynamic systems. Positive work is done by a system when it could potentially lift a mass. Heat is defined as energy transfer due solely to temperature differences. The chapter also covers various forms of work including displacement work, units of work and power, and the sign conventions for work and heat. It discusses different thermodynamic processes like isothermal, isovolumetric and polytropic processes. The path dependence and additivity of work are also covered.
This document provides an overview of work and heat concepts for an engineering thermodynamics course. It defines work as energy transfer associated with a force acting through a distance, and heat as energy transfer between systems due to a temperature difference. Moving boundary work from piston expansion and compression is discussed. Heat transfer occurs through conduction, convection and radiation. Both work and heat are energy transfer mechanisms between a system and its surroundings, and are path dependent rather than properties of a state. The objective is for students to understand these fundamental concepts of work, heat, and their comparison.
Energy Transfer
Energy can cross the boundaries of a closed system in the form of heat or work.
If the energy transfer across the boundaries of a closed system is due to a temperature difference, it is heat; otherwise, it is work.
Energy transferred across a system boundary that can be thought of as the energy expended to lift a weight is called work.
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internshi
This document defines key thermodynamic terms and concepts. It discusses systems and surroundings, open, closed, and isolated systems. It explains state functions like internal energy and enthalpy, and describes different types of processes including isothermal, adiabatic, and free expansion. Heat capacity and the relationship between Cp and Cv for ideal gases are also covered. Measurement of energy changes using calorimetry is briefly discussed.
1) The document discusses heat, work, and the first law of thermodynamics. It defines heat and work as the two types of energy transfer across boundaries of closed systems.
2) The first law of thermodynamics, also called the law of conservation of energy, states that the total energy of a system remains constant, with increases in internal energy equal to net heat and work transfers.
3) Specific examples are provided to illustrate the first law for closed systems undergoing various processes like heating, cooling, and adiabatic changes with and without work. Formulas are derived for calculating internal energy changes based on the first law.
1) This document discusses heat, work, and the first law of thermodynamics. It defines heat and work as the two ways energy can transfer across the boundary of a closed system, with heat transferring due to a temperature difference and work occurring from a force acting through a distance.
2) The first law of thermodynamics states that the change in a system's internal energy is equal to the net heat transferred to the system plus the net work done by the system. This is illustrated with examples of processes involving only heat transfer, where the energy change equals the net heat.
3) Different types of thermodynamic processes are examined, including isobaric, isochoric, isothermal, and poly
This chapter discusses work and heat transfer in thermodynamic systems. It defines work as force times distance for simple mechanical systems, and as the potential to lift a mass for thermodynamic systems. Positive work is done by a system when it could potentially lift a mass. Heat is defined as energy transfer due solely to temperature differences. The chapter also covers various forms of work including displacement work, units of work and power, and the sign conventions for work and heat. It discusses different thermodynamic processes like isothermal, isovolumetric and polytropic processes. The path dependence and additivity of work are also covered.
This document provides an overview of work and heat concepts for an engineering thermodynamics course. It defines work as energy transfer associated with a force acting through a distance, and heat as energy transfer between systems due to a temperature difference. Moving boundary work from piston expansion and compression is discussed. Heat transfer occurs through conduction, convection and radiation. Both work and heat are energy transfer mechanisms between a system and its surroundings, and are path dependent rather than properties of a state. The objective is for students to understand these fundamental concepts of work, heat, and their comparison.
Energy Transfer
Energy can cross the boundaries of a closed system in the form of heat or work.
If the energy transfer across the boundaries of a closed system is due to a temperature difference, it is heat; otherwise, it is work.
Energy transferred across a system boundary that can be thought of as the energy expended to lift a weight is called work.
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the year
Usey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internship of the yearUsey s m l m ankit r u in the evening sir in the world cup today to the dam to the day of my life and the day of the day and the day and the best for discontinue the internshi
This document defines key thermodynamic terms and concepts. It discusses systems and surroundings, open, closed, and isolated systems. It explains state functions like internal energy and enthalpy, and describes different types of processes including isothermal, adiabatic, and free expansion. Heat capacity and the relationship between Cp and Cv for ideal gases are also covered. Measurement of energy changes using calorimetry is briefly discussed.
Work done by constant volume and pressure using PV diagramayesha455941
This presentation discusses thermodynamic work and processes involving changes in pressure and volume. It begins by defining work as the energy transferred by a system to its surroundings. Work can be measured in joules or newton-meters. Pressure-volume work occurs when the volume of a system changes and is represented by the area under the pressure-volume curve. An isobaric process maintains constant pressure, while an isochoric process maintains constant volume. Pressure-volume diagrams are used to visualize these processes and calculate work done on a system based on changes in pressure and volume.
Energy Transport by Heat, Work and Mass (1).pptethiouniverse
Energy can exist in many forms and be transferred between systems in different ways. Heat is defined as energy transferred due to a temperature difference and work is done when a force causes a displacement. During a process, the total energy of an isolated system is conserved but may be transferred as heat or work that cross the system boundary. Heat transfer between systems occurs through conduction, convection or radiation, while work transfer involves interactions between a system and its surroundings.
1. The document discusses the second law of thermodynamics and the Carnot cycle.
2. A Carnot cycle involves four processes - two isothermal and two adiabatic reversible processes - between two heat reservoirs at different temperatures.
3. The maximum possible efficiency of any heat engine is given by the Carnot efficiency, which depends only on the temperatures of the heat reservoirs.
Heat and thermodynamics - Preliminary / Dr. Mathivanan VelumaniMathivanan Velumani
The document discusses key concepts in thermodynamics including:
1. Thermodynamic states are characterized by macroscopic properties like temperature, pressure, and volume that determine a system's internal state and interaction with external bodies.
2. Thermal equilibrium exists when temperature is uniform throughout a system, as stated by the zeroth law of thermodynamics.
3. Internal energy (U) is the energy associated with the random, disordered motion of molecules within a system.
The first law of thermodynamics states that the change in internal energy of a system is equal to the heat supplied to the system minus the work done by the system. For a closed system undergoing a process, this can be expressed as ΔU=Q-W. The first law applies to both closed systems undergoing non-flow processes as well as open systems undergoing steady flow processes. For non-flow processes such as constant volume, constant pressure, isothermal, and adiabatic processes, the first law allows determining the relationships between heat, work and changes in internal energy or enthalpy. For steady flow processes, the general energy equation accounts for changes in kinetic and potential energy of the fluid in addition to heat
Ch 3 energy transfer by work, heat and massabfisho
The document discusses energy transfer through heat, work, and mass. It defines key concepts like the first law of thermodynamics, heat transfer, work, power, and various types of work including boundary work, shaft work, spring work, and more. It provides equations to calculate work, heat transfer, and power for different processes. It includes several examples calculating work, heat transfer, and analyzing processes on P-V diagrams for closed systems operating in various thermodynamic cycles and processes.
The document discusses energy transfer through heat, work, and mass. It defines key concepts like the first law of thermodynamics, heat transfer, work, and explains various types of work including boundary work, shaft work, spring work, and more. It provides examples of calculating work done during various thermodynamic processes like isothermal, polytropic, constant pressure, and others. Sample problems are included and solved to illustrate applying the first law of thermodynamics to closed systems undergoing different processes.
The basic concepts in thermodynamics like thermodynamic system, thermodynamic variables, heat, cyclic process, zeroth law of thermodynamics, Carnot's heat engine, etc. are explained in this ppt.
This document provides an overview of thermodynamics concepts including:
1. Thermodynamics is the study of energy, work, and heat transfer between systems and their surroundings.
2. Examples of thermodynamic systems include engines and refrigerators which involve heat transfer and work.
3. The two laws of thermodynamics establish the limits of energy transfer and conversion between thermal reservoirs.
The document discusses the first law of thermodynamics. It provides equations and explanations for how the internal energy (U) of a system can change through heat (Q) added or removed from the system or work (W) done on or by the system. The first law is expressed as ΔU = Q - W. Specific processes discussed include adiabatic (no heat transfer), isobaric (constant pressure), isochoric (constant volume), and isothermal (constant temperature). Diagrams are used to illustrate these concepts and how to calculate work from changes in pressure and volume.
- Any reversible process can be approximated by a series of reversible, isothermal and reversible, adiabatic processes connected by intermediate states.
- The heat interaction along the reversible path is equal to the heat interaction along the reversible isothermal path between the same initial and final states.
- Therefore, a reversible process can be replaced by a zig-zag path consisting of reversible adiabatic and isothermal processes, satisfying the first law of thermodynamics.
- According to the Clausius theorem, the integral of heat transfer divided by temperature around any cyclic process is equal to zero for a reversible process. This leads to the definition of entropy as a state function.
This document provides an overview of key concepts in thermodynamics. It begins with contact information for the instructor, Dr. Sabar D. Hutagalung, and lists the main topics to be covered, including the four laws of thermodynamics. It then provides more detailed explanations of these topics, such as definitions of the zeroth, first, and second laws. It also explains concepts like heat, work, internal energy, and processes involving gases like isobaric, isothermal, and adiabatic. In addition, it discusses mechanisms of heat transfer including conduction, convection, and radiation, and defines important related terms.
This document defines key thermodynamic terms and concepts:
- A system is the part of the universe being studied, with the surroundings making up the rest. Systems can be open, closed, or isolated depending on energy/matter exchange.
- State functions like internal energy (U), enthalpy (H), and temperature (T) depend only on the current state and not the path to get there.
- The first law of thermodynamics states that energy is conserved, expressed as a change in internal energy (ΔU) equals heat (q) plus work (w).
- Enthalpy (H) includes pressure-volume work and is useful for constant pressure processes, where the heat of reaction
Energy transfer by heat occurs between systems with a temperature difference, even if no work is done. Heat transfer is driven by decreasing temperature, with a higher rate of transfer for larger temperature differences. Heat transfer between a system and its surroundings is represented by Q, with a positive Q indicating heat transfer to the system. For transient processes, the rate of energy transfer to or from a system can be determined by integrating heat (Q) and work (W) terms over time.
Unit no 1 fundamentals of thermodyanamicsATUL PRADHAN
The document provides information on various thermodynamics concepts:
- A pure substance has a constant composition, while a mixture consists of multiple substances.
- A system is the quantity of matter under analysis, and can be open, closed, or isolated based on mass and energy transfers.
- Thermodynamic properties include intensive properties like temperature and pressure, and extensive properties like volume and energy which depend on system mass.
- Processes involve system state changes or energy transfers. Equilibrium occurs when properties are uniform throughout the system.
Thermodynamics is the study of heat and its relation to other forms of energy. It describes the transformations of energy between heat and other forms, such as work. Some key concepts in thermodynamics include state properties like temperature and pressure, energy transfer as either heat or work, and the first and second laws of thermodynamics. Thermodynamic engines convert some heat into work based on these principles, with efficiency determined by the ratio of work output to heat input. Common applications include steam engines, gas turbines, and internal combustion engines.
Here are the key steps to derive the expression for heat of reaction at constant pressure:
1) For a chemical reaction occurring at constant pressure, the enthalpy change (ΔH) is equal to the heat absorbed or released by the system (qP).
2) Enthalpy change (ΔH) is defined as the change in internal energy (ΔU) plus the product of pressure (P) and change in volume (ΔV).
ΔH = ΔU + PΔV
3) For a reaction at constant pressure, the volume change (ΔV) is small and pressure remains constant.
4) From the first law of thermodynamics, the change in internal energy (Δ
- The document discusses thermodynamics concepts including the first law of thermodynamics for closed systems and boundary work.
- It provides examples of typical thermodynamic processes like constant volume, constant pressure, isothermal, and polytropic processes. Equations for calculating boundary work during these processes are given.
- Sample problems demonstrate using thermodynamic property relations and the concepts of boundary work to calculate work values for closed systems undergoing specified processes like isothermal compression of a gas.
This document discusses entropy and the second law of thermodynamics. It begins by introducing entropy as a property defined by applying the first law of thermodynamics to thermodynamic processes. The second law is then defined as the law of entropy. Key points covered include Clausius' theorem stating that the cyclic integral of heat transfer over temperature is zero for reversible cycles, and that entropy always increases for irreversible processes in isolated systems according to the entropy principle. Entropy is also described as being related to the disorder of a system.
- The first law of thermodynamics states that energy can change forms but cannot be created or destroyed.
- For a closed system undergoing a cycle, the net heat transfer equals the net work. For a closed system undergoing a change of state, the heat transfer equals the change in internal energy of the system plus any work done on or by the system.
- The first law also applies to open systems, where there is transfer of mass and energy into and out of the system. For a steady flow open system, the rate of increase of total energy entering the system must equal the rate of increase of total energy leaving the system.
Work done by constant volume and pressure using PV diagramayesha455941
This presentation discusses thermodynamic work and processes involving changes in pressure and volume. It begins by defining work as the energy transferred by a system to its surroundings. Work can be measured in joules or newton-meters. Pressure-volume work occurs when the volume of a system changes and is represented by the area under the pressure-volume curve. An isobaric process maintains constant pressure, while an isochoric process maintains constant volume. Pressure-volume diagrams are used to visualize these processes and calculate work done on a system based on changes in pressure and volume.
Energy Transport by Heat, Work and Mass (1).pptethiouniverse
Energy can exist in many forms and be transferred between systems in different ways. Heat is defined as energy transferred due to a temperature difference and work is done when a force causes a displacement. During a process, the total energy of an isolated system is conserved but may be transferred as heat or work that cross the system boundary. Heat transfer between systems occurs through conduction, convection or radiation, while work transfer involves interactions between a system and its surroundings.
1. The document discusses the second law of thermodynamics and the Carnot cycle.
2. A Carnot cycle involves four processes - two isothermal and two adiabatic reversible processes - between two heat reservoirs at different temperatures.
3. The maximum possible efficiency of any heat engine is given by the Carnot efficiency, which depends only on the temperatures of the heat reservoirs.
Heat and thermodynamics - Preliminary / Dr. Mathivanan VelumaniMathivanan Velumani
The document discusses key concepts in thermodynamics including:
1. Thermodynamic states are characterized by macroscopic properties like temperature, pressure, and volume that determine a system's internal state and interaction with external bodies.
2. Thermal equilibrium exists when temperature is uniform throughout a system, as stated by the zeroth law of thermodynamics.
3. Internal energy (U) is the energy associated with the random, disordered motion of molecules within a system.
The first law of thermodynamics states that the change in internal energy of a system is equal to the heat supplied to the system minus the work done by the system. For a closed system undergoing a process, this can be expressed as ΔU=Q-W. The first law applies to both closed systems undergoing non-flow processes as well as open systems undergoing steady flow processes. For non-flow processes such as constant volume, constant pressure, isothermal, and adiabatic processes, the first law allows determining the relationships between heat, work and changes in internal energy or enthalpy. For steady flow processes, the general energy equation accounts for changes in kinetic and potential energy of the fluid in addition to heat
Ch 3 energy transfer by work, heat and massabfisho
The document discusses energy transfer through heat, work, and mass. It defines key concepts like the first law of thermodynamics, heat transfer, work, power, and various types of work including boundary work, shaft work, spring work, and more. It provides equations to calculate work, heat transfer, and power for different processes. It includes several examples calculating work, heat transfer, and analyzing processes on P-V diagrams for closed systems operating in various thermodynamic cycles and processes.
The document discusses energy transfer through heat, work, and mass. It defines key concepts like the first law of thermodynamics, heat transfer, work, and explains various types of work including boundary work, shaft work, spring work, and more. It provides examples of calculating work done during various thermodynamic processes like isothermal, polytropic, constant pressure, and others. Sample problems are included and solved to illustrate applying the first law of thermodynamics to closed systems undergoing different processes.
The basic concepts in thermodynamics like thermodynamic system, thermodynamic variables, heat, cyclic process, zeroth law of thermodynamics, Carnot's heat engine, etc. are explained in this ppt.
This document provides an overview of thermodynamics concepts including:
1. Thermodynamics is the study of energy, work, and heat transfer between systems and their surroundings.
2. Examples of thermodynamic systems include engines and refrigerators which involve heat transfer and work.
3. The two laws of thermodynamics establish the limits of energy transfer and conversion between thermal reservoirs.
The document discusses the first law of thermodynamics. It provides equations and explanations for how the internal energy (U) of a system can change through heat (Q) added or removed from the system or work (W) done on or by the system. The first law is expressed as ΔU = Q - W. Specific processes discussed include adiabatic (no heat transfer), isobaric (constant pressure), isochoric (constant volume), and isothermal (constant temperature). Diagrams are used to illustrate these concepts and how to calculate work from changes in pressure and volume.
- Any reversible process can be approximated by a series of reversible, isothermal and reversible, adiabatic processes connected by intermediate states.
- The heat interaction along the reversible path is equal to the heat interaction along the reversible isothermal path between the same initial and final states.
- Therefore, a reversible process can be replaced by a zig-zag path consisting of reversible adiabatic and isothermal processes, satisfying the first law of thermodynamics.
- According to the Clausius theorem, the integral of heat transfer divided by temperature around any cyclic process is equal to zero for a reversible process. This leads to the definition of entropy as a state function.
This document provides an overview of key concepts in thermodynamics. It begins with contact information for the instructor, Dr. Sabar D. Hutagalung, and lists the main topics to be covered, including the four laws of thermodynamics. It then provides more detailed explanations of these topics, such as definitions of the zeroth, first, and second laws. It also explains concepts like heat, work, internal energy, and processes involving gases like isobaric, isothermal, and adiabatic. In addition, it discusses mechanisms of heat transfer including conduction, convection, and radiation, and defines important related terms.
This document defines key thermodynamic terms and concepts:
- A system is the part of the universe being studied, with the surroundings making up the rest. Systems can be open, closed, or isolated depending on energy/matter exchange.
- State functions like internal energy (U), enthalpy (H), and temperature (T) depend only on the current state and not the path to get there.
- The first law of thermodynamics states that energy is conserved, expressed as a change in internal energy (ΔU) equals heat (q) plus work (w).
- Enthalpy (H) includes pressure-volume work and is useful for constant pressure processes, where the heat of reaction
Energy transfer by heat occurs between systems with a temperature difference, even if no work is done. Heat transfer is driven by decreasing temperature, with a higher rate of transfer for larger temperature differences. Heat transfer between a system and its surroundings is represented by Q, with a positive Q indicating heat transfer to the system. For transient processes, the rate of energy transfer to or from a system can be determined by integrating heat (Q) and work (W) terms over time.
Unit no 1 fundamentals of thermodyanamicsATUL PRADHAN
The document provides information on various thermodynamics concepts:
- A pure substance has a constant composition, while a mixture consists of multiple substances.
- A system is the quantity of matter under analysis, and can be open, closed, or isolated based on mass and energy transfers.
- Thermodynamic properties include intensive properties like temperature and pressure, and extensive properties like volume and energy which depend on system mass.
- Processes involve system state changes or energy transfers. Equilibrium occurs when properties are uniform throughout the system.
Thermodynamics is the study of heat and its relation to other forms of energy. It describes the transformations of energy between heat and other forms, such as work. Some key concepts in thermodynamics include state properties like temperature and pressure, energy transfer as either heat or work, and the first and second laws of thermodynamics. Thermodynamic engines convert some heat into work based on these principles, with efficiency determined by the ratio of work output to heat input. Common applications include steam engines, gas turbines, and internal combustion engines.
Here are the key steps to derive the expression for heat of reaction at constant pressure:
1) For a chemical reaction occurring at constant pressure, the enthalpy change (ΔH) is equal to the heat absorbed or released by the system (qP).
2) Enthalpy change (ΔH) is defined as the change in internal energy (ΔU) plus the product of pressure (P) and change in volume (ΔV).
ΔH = ΔU + PΔV
3) For a reaction at constant pressure, the volume change (ΔV) is small and pressure remains constant.
4) From the first law of thermodynamics, the change in internal energy (Δ
- The document discusses thermodynamics concepts including the first law of thermodynamics for closed systems and boundary work.
- It provides examples of typical thermodynamic processes like constant volume, constant pressure, isothermal, and polytropic processes. Equations for calculating boundary work during these processes are given.
- Sample problems demonstrate using thermodynamic property relations and the concepts of boundary work to calculate work values for closed systems undergoing specified processes like isothermal compression of a gas.
This document discusses entropy and the second law of thermodynamics. It begins by introducing entropy as a property defined by applying the first law of thermodynamics to thermodynamic processes. The second law is then defined as the law of entropy. Key points covered include Clausius' theorem stating that the cyclic integral of heat transfer over temperature is zero for reversible cycles, and that entropy always increases for irreversible processes in isolated systems according to the entropy principle. Entropy is also described as being related to the disorder of a system.
- The first law of thermodynamics states that energy can change forms but cannot be created or destroyed.
- For a closed system undergoing a cycle, the net heat transfer equals the net work. For a closed system undergoing a change of state, the heat transfer equals the change in internal energy of the system plus any work done on or by the system.
- The first law also applies to open systems, where there is transfer of mass and energy into and out of the system. For a steady flow open system, the rate of increase of total energy entering the system must equal the rate of increase of total energy leaving the system.
The document discusses the Second Law of Thermodynamics in three main points:
1) The Second Law provides criteria to determine the probability and feasibility of processes, unlike the First Law. Spontaneous processes only occur in one direction, from high to low temperature, pressure, etc.
2) The Kelvin-Planck and Clausius statements of the Second Law establish that it is impossible for a heat engine to operate in a cycle using a single temperature reservoir or for heat to spontaneously flow from cold to hot.
3) An absolute temperature scale can be defined based on the Second Law and properties of Carnot engines, with the efficiency of reversible engines depending only on the temperature difference between reservoirs.
This document provides an introduction to thermodynamics. It defines thermodynamics as the science of energy transfer and its effect on physical properties. Thermodynamics studies systems, surroundings, properties, processes, and equilibrium from a macroscopic viewpoint. The document outlines concepts such as intensive and extensive properties, homogeneous and heterogeneous systems, quasi-static processes, and the zeroth law of thermodynamics. It provides examples to illustrate these fundamental thermodynamics concepts.
This document provides instructions and guidelines for using various tools needed for engineering drawing, including a drawing board, T-square, set squares, compass, scales, protractor, and French curves. It outlines best practices for drawing lines with the appropriate thickness for inked or pencil drawings. It also describes the different types of lines used in drawings like outlines, dimensions lines, and hidden lines. The document provides guidance on lettering, dimensioning, and general rules for laying out drawings, along with exercises for students.
The document discusses the equilibrium of rigid bodies, where a rigid body is defined as a solid body that does not deform under external forces. It states that the principle of transmissibility can be applied to rigid bodies, meaning that the point of application of a force can be moved along its line of action without changing the external reaction forces on the body. The principle also states that the equilibrium or motion of a rigid body remains unchanged if a force is replaced by an equal force in the same direction but acting at a different point, as long as they have the same line of action.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
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1. Work and heat transfer
-ppt-2
Engg Thermodynamics-ME2102
9/14/2020 1
Presented by,
Lalitha P
Asst. Professor
Mechanical Engg.
RGUKT Basar
2. Introduction
• A system and its surroundings can interact in two ways:
i. by work transfer, and
ii. by heat transfer
• These may be called energy interactions and these bring about
changes in the properties.
• TD mainly studies these energy interactions and the associated
property changes of the system.
9/14/2020 2
3. Path functions
• Process functions
• a quantity that is well defined
so as to describe the path of a
process through the equilibrium
state space of a TD s/m.
• Depends upon the path history.
Ie., defined to describe the path
of a process.
• Eg: work, heat: dW, dQ, etc.
Point functions
• State functions
• a variable each value of which
is associated with and
determined by the position of
some point in space.
• Does not vary with the path
history. i.e., defined by the
state variables.
• Eg: TD state variables: dV,
dp,dT, etc.
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4. 9/14/2020 4
•These are inexact differential,
so with the symbol
•Energy in transit is path
function
•Eg: work transfer and heat
transfer
• These are exact differential, so
with the symbol
•Energy in storage is point
function
•Eg: internal energy
5. Work transfer
• Work is one of the basic mode of energy transfer, the action of a
force on a moving object is identified as work.
• Mechanical work is defined as, the work is done by a force as it
acts upon a body moving in the direction of the force.
• In TD, work transfer (W) is considered as occurring between the
s/m and the surroundings.
• Work is said to be done by a s/m if the sole effect on things
external to the system can be reduced to the raising of a weight.
9/14/2020 5
6. • Work transfer is a boundary phenomenon.
• When work is done by a system, it is arbitrarily taken to be
positive.
• And when work is done on a system, it is taken to be negative.
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7. 9/14/2020 7
Types of Work transfer
1. Displacement or pdV work transfer
2. Paddle wheel work
3. Flow work
4. Shaft work
1. Displacement or pdV - work transfer
• Due to displacement of the system boundary of a closed system.
8. • Piston is the only boundary which moves due to gas pressure.
• When piston moves out from the equilm state ‘1’ to ‘2’,
infinitesimal displaced distance is ‘dl’ due to the force ‘F’ acting
on the piston.
• Where, ‘F’ is the pressure force as ‘ F = p.A’ , here, ‘p’ is gass
pressure and ‘A’ is piston surface area.
• Then the infinitesimal work done by the gas on piston is
• i.e., dW = F.dl = (p.A).dl = p.(A.dl) = p.dV
• Hence,
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dW = pdV
9. • Therefore, total work done on the piston by the gas is
• Explanation:
9/14/2020 9
10. • For a process 1-2, if path is defined well then one can calculate
the work transfer the process.
• On the above diagram, a quasi-static process is assumed with a
definite path. It is shown on a p-V diagram, if dW = pdV, then the
area under the curve (quasi-static process 1-2) on a p-V diagram
gives the total work transfer.
• To calculate total W, take a strip under the curve with average
height ‘p’ and width ‘dV’ gives you the area of the strip as ‘pdV’.
i.e., dW = pdV. For the total area under the curve (total work
transfer), do the integration from the initial state limit to final
state limit. As the V is the variable on the work relation, apply the
limits as V1 and V2.
• Therefore, total work transferred during the process 1-2 is,
• Work is a path function so on the subscript of W ‘ path 1-2’ is mentioned.
9/14/2020 10
11. Displacement or pdV-work – contd…
• For a process 1-2, Work done can be calculated
as
• For a cyclic process, initial and final process are same, so change
in any property is zero.
• i.e., cyclic integral of any property is always zero.
• [so, for a cyclic process, work W can not be calculated as
Since, .]
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12. 2. Stirrer or paddle wheel work or stirring work
• Here, friction is the work transfer agent.
• Work is added to the system through the paddle wheel, due to
the paddle wheel rotation system molecules displaces rapidly as
the result of collision on the paddle wheel and also by colliding
each other. It increases the molecular friction, that leads to
increase in temperature further other properties of the system
change.
• It is a closed system process.
9/14/2020 12
14. • It is the work required to push a certain quantity of fluid across a
system.
• It is an open system process.
• To push ‘dm’ mass of fluid against the pressure ‘p’ exerted by the
system, external force ‘F’ will be applied.
• External force, F = p.A
so, work transfer W = F.dx = (p.A).dx
Work transfer per unit mass is defined as the flow work.
Therefore, W/mass =
Since, specific volume ( ) is , then,
The work transferred while transferring the mass of fluid is,
9/14/2020 14
15. 4. shaft work
• It develops power through a rotating shaft against a resisting
torque.
• Work is given through the rotating shaft or work can be
developed through the shaft.
9/14/2020 15
16. pdV work in various quasi-static processes
1. Constant pressure (p=c) process
• Isobaric process or isopiestic process
• Work done by the system for the process 1-2 is
since, p1 =p2 = p = c
9/14/2020 16
17. 2. Constant volume (V=c) process
• Isochoric process
• Work done by the system for the process 1-2 is
since, V1 =V2 = V = c
9/14/2020 17
18. 3. Process in which pV = C
• Work done by the system for the process
can be calculated as
• Therefore, work done by the system for the process 1-2 is
since,
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19. 4. Process in which pV^n = C where n is a constant which is varies
from 0 to ∞.
• Work done by the system for the
process can be calculated as
9/14/2020 19
20. • Therefore, work done by the system for the process 1-2 is
since,
Here,
Or,
9/14/2020 20
21. Free expansion with zero work transfer
• Expansion of gas against a vacuum is called free expansion.
• Assuming a system with two compartments in which one is filled
with gas and the other one is vacuumised. These two
compartments are separated by a partition which a thin
membrane. When the partition is removed, gas rushes to fill the
entire volume of the system by expanding to the vacuumised
compartment. Note that the work given for the removal of
partition is negligible, and hence with no work gas is expanded.
This process of expansion of gas without any work transfer across
the system boundary is called free expansion. i.e.,
9/14/2020 21
22. Contd…
• Now assume that system is only the gas, then after the removal of
partition, gas expands to the vacuum.
• This process is not a quasi-static process since, the path of gas
expansion will not be able to define due to a rapid expansion of gas.
• In this case, to get a quasi-static process, in the vacuum
compartments, place more no.of partitions. By removing each and
every partitions slowly and steadily, gas expands to the vacuum with
no resistance so that we can achieve intermediate equilibrium states
and hence the path can be identified.(Here also work involved to
remove all the partitions is neglected.)
9/14/2020 22
23. HEAT TRANSFER
• Another form of energy in transit.
• Due to the temperature difference between the system and
surroundings heat energy will be transferred. Its a boundary
phenomenon occurs only across the boundary of the system. i.e.,
• “Heat is a form of energy that is transferred across a boundary by
virtue of temperature difference.”
• Heat transfer (HT) occurs from high temperature system to low
temperature system.
Types of HT
i. Conduction : HT between two bodies in direct contact.
ii. Convection : HT by mass transfer, as transfer of heat between a
wall and fluid system in motion.
iii. Radiation : two bodies are separated by empty space or gases
and heat transfers only through electromagnetic waves.
9/14/2020 23
24. Contd…
Sign convention
Positive HT: when heat flows into a system (heat addition)
Negative HT: when heat flows out a system (heat rejection)
• The symbol ‘Q’ is used for heat transfer.
• HT is the quantity of heat transferred within a certain time.
• Hence, unit of heat is Joule (J) and heat transfer is J/s or Watt (W)
in S.I. units.
9/14/2020 24
25. Contd…
• Heat is not that inevitably cause a temperature rise. Similar to
heat transfer, work transfer may also lead to the temperature rise
in a system. Work or heat is not a conserved quantity, and also not
system property.
• In a process in which no heat crosses the boundary of the system
is called an adiabatic process. In an adiabatic process, there is only
work interaction between the s/m and its surroundings.
• A wall which is impermeable to the flow of heat is an adiabatic
wall, whereas a wall which permits the heat flow is diathermic
wall.
• Heat transfer is a path function.
9/14/2020 25
26. Contd…
• Heat transfer (Q) can be
calculated by using the
similar method we used to
calculate the work transfer.
• So, the HT for the process 1-2
is
• Note that dQ is inexact differential. To get heat transfer quantity,
we need to convert inexact differential to exact differential by
multiplying it is by an integrating factor.
9/14/2020 26
27. Specific heat and latent heat
Specific heat : amount of heat required to raise a unit mass of the
substance through a unit temperature raise. i.e.,
• sp.heat (c) can be obtained by the process of HT.
If the process is a constant pressure (p = C), then sp.heat is called as
sp.heat at constant pressure, .
If the process is a constant volume(V = C), then sp.heat is called as
sp.heat at constant volume, .
• Heat capacity (C) of the substance = mass of the substance × sp.heat.
• i.e., C = mc
9/14/2020 27
28. Latent heat : Amount of heat required to change a phase in unit mass of
a substance at constant pressure and constant temperature. i.e.,
Types:
i. Latent heat of fusion(lfu) : amount of heat transferred to melt a solid
to liquid or liquid to solid.
ii. Latent heat of vapourization (lvap) : amount of heat transferred to
convert liquid to vapour or vapour to liquid (latent heat of
condensation).
iii. Latent heat of sublimation (lsub) : heat transferred to convert solid
to vapour or vapour to solid.
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