The document discusses different types of engine cycles including ideal, fuel-air, and actual cycles. It provides details on:
- Air standard cycles which are idealized and assume a perfect gas, no mass change, reversible processes, and constant specific heats. Examples include Otto, Diesel, and Dual cycles.
- Fuel-air cycles which are more accurate by considering the actual cylinder gas composition, variable specific heats, incomplete fuel-air mixing at high temps, and dissociation effects.
- Actual engine cycles use even more accurate models of the processes and working fluid, taking into account variable properties and chemical reactions.
This document discusses various thermodynamic power cycles used in internal combustion engines. It describes air standard cycles which approximate actual engine cycles using assumptions like ideal gas behavior and reversible processes. The key cycles covered are:
- Carnot cycle, the most efficient theoretical cycle but impractical to implement.
- Otto cycle for spark ignition engines, with efficiency increasing with compression ratio.
- Diesel cycle for compression ignition engines, allowing higher compression ratios and efficiencies than Otto cycle.
- Dual combustion cycle as a better approximation for modern diesel engines where combustion occurs in two stages.
The document analyzes each cycle thermodynamically and compares the efficiencies of Otto, Diesel and Dual cycles at
The document discusses gas turbine cycles and thermodynamic cycles used in gas turbines. It begins by describing air standard cycles and assumptions made, including the working fluid behaving as an ideal gas. It then discusses the Otto cycle which models spark ignition engines and the processes involved. Details of the Otto cycle calculation are provided. The document also discusses the diesel cycle which models compression ignition engines and provides cycle calculations. Other topics covered include mean effective pressure, engine terminology, gas turbine components and cycles like the Brayton cycle.
Thermodynamics chapter:7 Some Power and Refrigerator Cycle Ashok giri
This document discusses power and refrigeration cycles. It provides classifications of cycles based on whether they produce or absorb work, the working fluid used, and the type of heat supplied. The key components of cycles are identified as the heat source, heat sink, and working fluid. The Brayton cycle is described as a gas turbine cycle consisting of constant pressure heat addition and rejection processes separated by isentropic compression and expansion. Expressions for the efficiency of the Brayton cycle are provided. Internal combustion cycles like the Otto and Diesel cycles are discussed as idealized air-standard cycles with assumptions made about the working fluid. The four processes and efficiency equations for the Otto and Diesel cycles are summarized.
This chapter discusses gas power cycles where the working fluid remains a gas throughout. It introduces the ideal Carnot cycle and air-standard assumptions used to model real cycles. The chapter analyzes the Otto, Diesel, Stirling, Ericsson and Brayton cycles. It discusses the use of regeneration, intercooling and reheating to improve the Brayton cycle efficiency. The chapter also covers jet propulsion cycles and modifications like turbofans. Real cycles deviate from ideal cycles due to irreversibilities. The chapter provides examples to calculate cycle parameters and efficiencies.
The fuel-air cycle provides a more accurate model of the actual thermodynamic cycle in an internal combustion engine compared to the air standard cycle by accounting for:
1) The actual composition of gases in the cylinder, which varies throughout the cycle.
2) Variations in specific heat and dissociation effects at high temperatures.
3) Changes in the number of moles as pressure and temperature fluctuate.
The fuel-air cycle shows that efficiency is maximized with a slightly rich mixture near stoichiometric due to higher temperatures from dissociation. It also demonstrates efficiency gains from higher compression but losses from richer mixtures beyond stoichiometric due to incomplete combustion.
The document discusses the idealized air standard diesel cycle that is used to analyze internal combustion engine processes. It describes how the actual open cycle is approximated as a closed cycle by assuming exhaust gases are recycled. It also outlines how the combustion process is replaced with constant pressure heat addition and other actual processes are approximated using ideal processes like constant pressure and isentropic. Finally, it provides the thermodynamic analysis of the six processes that make up the air standard diesel cycle and gives the equation to calculate the cycle's thermal efficiency.
The document provides information on internal combustion engines, including:
- IC engines convert chemical energy from fuels like gasoline into mechanical work. They are used in vehicles, generators, and other machinery.
- The basic components of IC engines are cylinders, pistons, inlet/exhaust valves. Pistons move between top and bottom dead centers.
- IC engines are classified as either spark-ignition (gasoline) or compression-ignition (diesel) based on how combustion is initiated in the cylinder.
The document then discusses air standard cycles that model idealized versions of engine cycles, including the Otto cycle for gasoline engines and Diesel cycle for diesel engines. It provides analysis of the cycles
The document discusses different types of engine cycles including ideal, fuel-air, and actual cycles. It provides details on:
- Air standard cycles which are idealized and assume a perfect gas, no mass change, reversible processes, and constant specific heats. Examples include Otto, Diesel, and Dual cycles.
- Fuel-air cycles which are more accurate by considering the actual cylinder gas composition, variable specific heats, incomplete fuel-air mixing at high temps, and dissociation effects.
- Actual engine cycles use even more accurate models of the processes and working fluid, taking into account variable properties and chemical reactions.
This document discusses various thermodynamic power cycles used in internal combustion engines. It describes air standard cycles which approximate actual engine cycles using assumptions like ideal gas behavior and reversible processes. The key cycles covered are:
- Carnot cycle, the most efficient theoretical cycle but impractical to implement.
- Otto cycle for spark ignition engines, with efficiency increasing with compression ratio.
- Diesel cycle for compression ignition engines, allowing higher compression ratios and efficiencies than Otto cycle.
- Dual combustion cycle as a better approximation for modern diesel engines where combustion occurs in two stages.
The document analyzes each cycle thermodynamically and compares the efficiencies of Otto, Diesel and Dual cycles at
The document discusses gas turbine cycles and thermodynamic cycles used in gas turbines. It begins by describing air standard cycles and assumptions made, including the working fluid behaving as an ideal gas. It then discusses the Otto cycle which models spark ignition engines and the processes involved. Details of the Otto cycle calculation are provided. The document also discusses the diesel cycle which models compression ignition engines and provides cycle calculations. Other topics covered include mean effective pressure, engine terminology, gas turbine components and cycles like the Brayton cycle.
Thermodynamics chapter:7 Some Power and Refrigerator Cycle Ashok giri
This document discusses power and refrigeration cycles. It provides classifications of cycles based on whether they produce or absorb work, the working fluid used, and the type of heat supplied. The key components of cycles are identified as the heat source, heat sink, and working fluid. The Brayton cycle is described as a gas turbine cycle consisting of constant pressure heat addition and rejection processes separated by isentropic compression and expansion. Expressions for the efficiency of the Brayton cycle are provided. Internal combustion cycles like the Otto and Diesel cycles are discussed as idealized air-standard cycles with assumptions made about the working fluid. The four processes and efficiency equations for the Otto and Diesel cycles are summarized.
This chapter discusses gas power cycles where the working fluid remains a gas throughout. It introduces the ideal Carnot cycle and air-standard assumptions used to model real cycles. The chapter analyzes the Otto, Diesel, Stirling, Ericsson and Brayton cycles. It discusses the use of regeneration, intercooling and reheating to improve the Brayton cycle efficiency. The chapter also covers jet propulsion cycles and modifications like turbofans. Real cycles deviate from ideal cycles due to irreversibilities. The chapter provides examples to calculate cycle parameters and efficiencies.
The fuel-air cycle provides a more accurate model of the actual thermodynamic cycle in an internal combustion engine compared to the air standard cycle by accounting for:
1) The actual composition of gases in the cylinder, which varies throughout the cycle.
2) Variations in specific heat and dissociation effects at high temperatures.
3) Changes in the number of moles as pressure and temperature fluctuate.
The fuel-air cycle shows that efficiency is maximized with a slightly rich mixture near stoichiometric due to higher temperatures from dissociation. It also demonstrates efficiency gains from higher compression but losses from richer mixtures beyond stoichiometric due to incomplete combustion.
The document discusses the idealized air standard diesel cycle that is used to analyze internal combustion engine processes. It describes how the actual open cycle is approximated as a closed cycle by assuming exhaust gases are recycled. It also outlines how the combustion process is replaced with constant pressure heat addition and other actual processes are approximated using ideal processes like constant pressure and isentropic. Finally, it provides the thermodynamic analysis of the six processes that make up the air standard diesel cycle and gives the equation to calculate the cycle's thermal efficiency.
The document provides information on internal combustion engines, including:
- IC engines convert chemical energy from fuels like gasoline into mechanical work. They are used in vehicles, generators, and other machinery.
- The basic components of IC engines are cylinders, pistons, inlet/exhaust valves. Pistons move between top and bottom dead centers.
- IC engines are classified as either spark-ignition (gasoline) or compression-ignition (diesel) based on how combustion is initiated in the cylinder.
The document then discusses air standard cycles that model idealized versions of engine cycles, including the Otto cycle for gasoline engines and Diesel cycle for diesel engines. It provides analysis of the cycles
The document provides information on several thermodynamic cycles used in power plants and engines, including:
1) The Carnot, Stirling, Ericsson, Brayton, Rankine, and Otto cycles. Equations for calculating efficiency are provided for some cycles.
2) Diagrams show the pressure-volume or temperature-entropy processes involved in each cycle. The Carnot cycle involves two isothermal and two adiabatic processes. The Stirling cycle has four processes: two isothermal and two isochoric.
3) The Rankine cycle closely describes the steam power cycle. It involves isobaric heating of liquid to steam, isentropic expansion in a turbine, isobar
The document contains multiple choice and short answer questions related to thermodynamics and heat engines. Some sample questions include identifying the process represented by lines on a T-s diagram, defining key thermodynamic cycles like Otto and Diesel, and calculating efficiency and heat supplied for ideal Brayton cycles. Short answer questions provide definitions for terms like refrigerating capacity and differentiate concepts such as normal and shear stress. Numerical problems involve truss analysis and calculating properties of gas turbine cycles.
The document discusses various air standard cycles that are used to model internal combustion engine processes, including the Otto, Diesel, and dual cycles. It provides details on the assumptions and thermodynamic processes that define each cycle. The Otto cycle consists of four processes: constant-pressure intake, isentropic compression, constant-volume combustion, and isentropic expansion. The Diesel cycle models combustion as a constant-pressure process rather than constant volume. The dual cycle models combustion as both constant-volume and constant-pressure processes. Comparisons are made between the cycles in terms of their heat transfer and thermal efficiencies.
This document discusses air cycle refrigeration systems used in aircraft cabin cooling. It begins by introducing air cycle refrigeration and its advantages for aircraft applications. It then describes the ideal reverse Brayton cycle and compares it to the Carnot cycle. Key concepts of compression, expansion, and heat transfer processes are explained. Actual cycle analysis accounts for irreversibilities. Common aircraft refrigeration cycles are introduced, including the simple cycle and bootstrap system. The bootstrap system improves on the simple cycle by using a secondary compressor to boost efficiency during high-speed flight when ram air is available.
This document describes the reciprocating internal combustion engine. It discusses key components like the cylinder, piston, connecting rod and crankshaft. It also covers the classification of IC engines based on factors like fuel type, cooling method and cylinder arrangement. The four main components of a four-stroke engine are the intake, compression, power and exhaust strokes. The air standard Otto cycle and Diesel cycle are theoretical cycles that simplify actual engine conditions. While useful for approximations, the actual engine cycle has additional complexities and losses compared to the idealized cycles.
Course in Pune University Mechanical Engineering ppt based on Engineering Fundamentals
of the
Internal Combustion Engine
Willard W. Pulkrabek
University of Wisconsin-· .. Platteville
The document provides an overview of internal combustion engines. It discusses the basic classifications and cycles of internal combustion engines including two-stroke and four-stroke engines. It also covers the workings of spark ignition and compression ignition engines, as well as common engine components and systems such as carburetors and fuel injection systems. Key topics include the Otto, Diesel, and Carnot power cycles; combustion stages; valve timing diagrams; and scavenging, pre-ignition, detonation, lubrication, and emissions control.
The document discusses internal combustion engines, including the workings of 4-stroke spark ignition and diesel engines. It defines external and internal combustion engines, explaining the 4 strokes of a gasoline engine: intake, compression, combustion/power, and exhaust. It also covers the 4 strokes of a diesel engine and compares the 2 engine types. The document lists assumptions for the Otto and diesel cycles and derives the efficiency expressions for both cycles. It differentiates between 2-stroke and 4-stroke engines and compares petrol and diesel engines.
The document summarizes air cycle refrigeration systems used for aircraft cabin cooling. It describes the simple cycle, which uses ram air compressed by the aircraft's motion and a turbine to provide cooled air. It also discusses more complex cycles like the bootstrap and regenerative systems that use additional compressors and heat exchangers. These systems can provide cooler air at higher speeds without needing a separate fan. The document compares the performance of different cycles using the concept of dry air rated temperature to rate their cooling capacities.
This document discusses the Diesel and Brayton thermodynamic cycles. It provides details on:
- The history and development of the Diesel cycle, invented by Rudolf Diesel in 1893, including its use of compression ignition and the differences from the Otto cycle.
- The thermodynamic processes that characterize the Diesel cycle and how it has evolved from early constant pressure combustion to the modern dual cycle with both constant pressure and volume combustion.
- The Brayton cycle, introduced in 1872, which uses separate compression and expansion cylinders and constant combustion.
- The ideal processes that make up the Brayton cycle and how to analyze it thermally using pressure and temperature ratios along with the concepts of back
The document discusses various air standard cycles used to model internal combustion engines, including assumptions made. It describes the Carnot, Otto, Diesel, Dual Combustion, and Brayton (Joule) cycles. Each cycle consists of different thermodynamic processes like constant volume heat addition, constant pressure heat addition, adiabatic compression/expansion. The document also provides an overview of internal combustion engines, their classification as spark ignition or compression ignition, and basic components of gasoline and diesel engines.
1. The document discusses actual and ideal thermodynamic cycles used in engines. It covers the Carnot, Otto, Diesel, and Dual cycles.
2. It then discusses fuel-air cycles which more accurately model the working fluid compared to ideal cycles. Fuel-air cycles account for variable specific heats, molecular effects, and dissociation losses.
3. The key differences between ideal, air standard, and actual engine cycles are analyzed. Actual cycles more accurately model processes and working fluids compared to ideal cycles but are more complex.
This document summarizes key concepts in thermodynamics and different thermodynamic cycles used in power generation. It discusses the four main thermodynamic processes: isobaric, isochoric, isothermal, and adiabatic. It then describes important thermodynamic cycles like Rankine, Brayton, Otto, and Diesel that are used in steam turbines, gas turbines, and reciprocating engines. Key components of each cycle are defined along with diagrams of typical systems.
This document summarizes the key components and operation of internal combustion engines. It discusses:
- The definitions of engines and heat engines and classifications of engines as rotary, reciprocating, external combustion, and internal combustion.
- The major components of engines like the cylinder, piston, combustion chamber, valves, and their functions.
- The operating cycles of 4-stroke spark ignition engines and 4-stroke compression ignition engines through their intake, compression, combustion, and exhaust strokes.
- Comparisons between spark ignition and compression ignition engines and between 2-stroke and 4-stroke engines.
- Differences between ideal engine diagrams and actual engine performance.
The document describes the working principles of a heat engine. It begins by explaining that a heat engine takes in energy by heat from a high temperature reservoir and expels a fraction of that energy as work during a cyclic process. It then provides more details on the specific processes involved, including absorbing heat, rejecting heat to a lower temperature reservoir, and doing work. The thermal efficiency of a heat engine is also defined.
The document provides an overview of different types of reciprocating engine cycles, including definitions of key terms, equations, and efficiency calculations. It describes the ideal Otto, Diesel, and dual combustion cycles. It includes equations to calculate efficiency, temperatures, pressures, work output, and mean effective pressure. It concludes with sample problems to calculate values for each cycle type.
This document discusses various gas power cycles used in engines. It describes the Otto, Diesel, dual, and Brayton cycles. The Otto cycle models spark ignition engines using four processes: isentropic compression, constant volume combustion, isentropic expansion, and constant volume exhaust. The Diesel cycle also uses four processes but replaces constant volume combustion with constant pressure combustion. The dual cycle combines aspects of the Otto and Diesel cycles. The Brayton cycle models gas turbines using constant pressure processes. Real examples of engines using these cycles are also provided.
The document discusses thermal power plants and the thermodynamic processes involved. It describes the basic energy cycle from chemical to mechanical to electrical energy. It then explains various thermodynamic processes like isobaric, isothermal, adiabatic, and isentropic. It discusses the throttling process and its uses. It also summarizes the four laws of thermodynamics. Finally, it describes important thermodynamic power cycles like Carnot, Rankine, Brayton, and combined cycles as well as ways to improve the efficiency of the Rankine cycle.
1) The document describes the working principle of an open cycle gas turbine, which consists of a compressor, combustion chamber, and gas turbine mounted on the same shaft.
2) It then discusses the Brayton cycle, which models the open cycle gas turbine as a closed cycle using a combustion heat exchanger and chiller heat exchanger to recirculate the working fluid.
3) The document lists some advantages and disadvantages of open cycle gas turbines, such as their simplicity but also high air rate and sensitivity to changes in efficiency and temperature.
The document provides information on several thermodynamic cycles used in power plants and engines, including:
1) The Carnot, Stirling, Ericsson, Brayton, Rankine, and Otto cycles. Equations for calculating efficiency are provided for some cycles.
2) Diagrams show the pressure-volume or temperature-entropy processes involved in each cycle. The Carnot cycle involves two isothermal and two adiabatic processes. The Stirling cycle has four processes: two isothermal and two isochoric.
3) The Rankine cycle closely describes the steam power cycle. It involves isobaric heating of liquid to steam, isentropic expansion in a turbine, isobar
The document contains multiple choice and short answer questions related to thermodynamics and heat engines. Some sample questions include identifying the process represented by lines on a T-s diagram, defining key thermodynamic cycles like Otto and Diesel, and calculating efficiency and heat supplied for ideal Brayton cycles. Short answer questions provide definitions for terms like refrigerating capacity and differentiate concepts such as normal and shear stress. Numerical problems involve truss analysis and calculating properties of gas turbine cycles.
The document discusses various air standard cycles that are used to model internal combustion engine processes, including the Otto, Diesel, and dual cycles. It provides details on the assumptions and thermodynamic processes that define each cycle. The Otto cycle consists of four processes: constant-pressure intake, isentropic compression, constant-volume combustion, and isentropic expansion. The Diesel cycle models combustion as a constant-pressure process rather than constant volume. The dual cycle models combustion as both constant-volume and constant-pressure processes. Comparisons are made between the cycles in terms of their heat transfer and thermal efficiencies.
This document discusses air cycle refrigeration systems used in aircraft cabin cooling. It begins by introducing air cycle refrigeration and its advantages for aircraft applications. It then describes the ideal reverse Brayton cycle and compares it to the Carnot cycle. Key concepts of compression, expansion, and heat transfer processes are explained. Actual cycle analysis accounts for irreversibilities. Common aircraft refrigeration cycles are introduced, including the simple cycle and bootstrap system. The bootstrap system improves on the simple cycle by using a secondary compressor to boost efficiency during high-speed flight when ram air is available.
This document describes the reciprocating internal combustion engine. It discusses key components like the cylinder, piston, connecting rod and crankshaft. It also covers the classification of IC engines based on factors like fuel type, cooling method and cylinder arrangement. The four main components of a four-stroke engine are the intake, compression, power and exhaust strokes. The air standard Otto cycle and Diesel cycle are theoretical cycles that simplify actual engine conditions. While useful for approximations, the actual engine cycle has additional complexities and losses compared to the idealized cycles.
Course in Pune University Mechanical Engineering ppt based on Engineering Fundamentals
of the
Internal Combustion Engine
Willard W. Pulkrabek
University of Wisconsin-· .. Platteville
The document provides an overview of internal combustion engines. It discusses the basic classifications and cycles of internal combustion engines including two-stroke and four-stroke engines. It also covers the workings of spark ignition and compression ignition engines, as well as common engine components and systems such as carburetors and fuel injection systems. Key topics include the Otto, Diesel, and Carnot power cycles; combustion stages; valve timing diagrams; and scavenging, pre-ignition, detonation, lubrication, and emissions control.
The document discusses internal combustion engines, including the workings of 4-stroke spark ignition and diesel engines. It defines external and internal combustion engines, explaining the 4 strokes of a gasoline engine: intake, compression, combustion/power, and exhaust. It also covers the 4 strokes of a diesel engine and compares the 2 engine types. The document lists assumptions for the Otto and diesel cycles and derives the efficiency expressions for both cycles. It differentiates between 2-stroke and 4-stroke engines and compares petrol and diesel engines.
The document summarizes air cycle refrigeration systems used for aircraft cabin cooling. It describes the simple cycle, which uses ram air compressed by the aircraft's motion and a turbine to provide cooled air. It also discusses more complex cycles like the bootstrap and regenerative systems that use additional compressors and heat exchangers. These systems can provide cooler air at higher speeds without needing a separate fan. The document compares the performance of different cycles using the concept of dry air rated temperature to rate their cooling capacities.
This document discusses the Diesel and Brayton thermodynamic cycles. It provides details on:
- The history and development of the Diesel cycle, invented by Rudolf Diesel in 1893, including its use of compression ignition and the differences from the Otto cycle.
- The thermodynamic processes that characterize the Diesel cycle and how it has evolved from early constant pressure combustion to the modern dual cycle with both constant pressure and volume combustion.
- The Brayton cycle, introduced in 1872, which uses separate compression and expansion cylinders and constant combustion.
- The ideal processes that make up the Brayton cycle and how to analyze it thermally using pressure and temperature ratios along with the concepts of back
The document discusses various air standard cycles used to model internal combustion engines, including assumptions made. It describes the Carnot, Otto, Diesel, Dual Combustion, and Brayton (Joule) cycles. Each cycle consists of different thermodynamic processes like constant volume heat addition, constant pressure heat addition, adiabatic compression/expansion. The document also provides an overview of internal combustion engines, their classification as spark ignition or compression ignition, and basic components of gasoline and diesel engines.
1. The document discusses actual and ideal thermodynamic cycles used in engines. It covers the Carnot, Otto, Diesel, and Dual cycles.
2. It then discusses fuel-air cycles which more accurately model the working fluid compared to ideal cycles. Fuel-air cycles account for variable specific heats, molecular effects, and dissociation losses.
3. The key differences between ideal, air standard, and actual engine cycles are analyzed. Actual cycles more accurately model processes and working fluids compared to ideal cycles but are more complex.
This document summarizes key concepts in thermodynamics and different thermodynamic cycles used in power generation. It discusses the four main thermodynamic processes: isobaric, isochoric, isothermal, and adiabatic. It then describes important thermodynamic cycles like Rankine, Brayton, Otto, and Diesel that are used in steam turbines, gas turbines, and reciprocating engines. Key components of each cycle are defined along with diagrams of typical systems.
This document summarizes the key components and operation of internal combustion engines. It discusses:
- The definitions of engines and heat engines and classifications of engines as rotary, reciprocating, external combustion, and internal combustion.
- The major components of engines like the cylinder, piston, combustion chamber, valves, and their functions.
- The operating cycles of 4-stroke spark ignition engines and 4-stroke compression ignition engines through their intake, compression, combustion, and exhaust strokes.
- Comparisons between spark ignition and compression ignition engines and between 2-stroke and 4-stroke engines.
- Differences between ideal engine diagrams and actual engine performance.
The document describes the working principles of a heat engine. It begins by explaining that a heat engine takes in energy by heat from a high temperature reservoir and expels a fraction of that energy as work during a cyclic process. It then provides more details on the specific processes involved, including absorbing heat, rejecting heat to a lower temperature reservoir, and doing work. The thermal efficiency of a heat engine is also defined.
The document provides an overview of different types of reciprocating engine cycles, including definitions of key terms, equations, and efficiency calculations. It describes the ideal Otto, Diesel, and dual combustion cycles. It includes equations to calculate efficiency, temperatures, pressures, work output, and mean effective pressure. It concludes with sample problems to calculate values for each cycle type.
This document discusses various gas power cycles used in engines. It describes the Otto, Diesel, dual, and Brayton cycles. The Otto cycle models spark ignition engines using four processes: isentropic compression, constant volume combustion, isentropic expansion, and constant volume exhaust. The Diesel cycle also uses four processes but replaces constant volume combustion with constant pressure combustion. The dual cycle combines aspects of the Otto and Diesel cycles. The Brayton cycle models gas turbines using constant pressure processes. Real examples of engines using these cycles are also provided.
The document discusses thermal power plants and the thermodynamic processes involved. It describes the basic energy cycle from chemical to mechanical to electrical energy. It then explains various thermodynamic processes like isobaric, isothermal, adiabatic, and isentropic. It discusses the throttling process and its uses. It also summarizes the four laws of thermodynamics. Finally, it describes important thermodynamic power cycles like Carnot, Rankine, Brayton, and combined cycles as well as ways to improve the efficiency of the Rankine cycle.
1) The document describes the working principle of an open cycle gas turbine, which consists of a compressor, combustion chamber, and gas turbine mounted on the same shaft.
2) It then discusses the Brayton cycle, which models the open cycle gas turbine as a closed cycle using a combustion heat exchanger and chiller heat exchanger to recirculate the working fluid.
3) The document lists some advantages and disadvantages of open cycle gas turbines, such as their simplicity but also high air rate and sensitivity to changes in efficiency and temperature.
Similar to Chapter 2 .pptxvbbhdsssfghjnbxssscbnnxaasvn (20)
This document provides an overview and outline for a Mechanical Engineering Design Project course (MECH 390). It discusses expectations for the course which include completing a design project in a team, taking a midterm exam, tutorials, and quizzes. Students are expected to apply engineering skills to open-ended problems through concepts, solutions, planning, decision making, modeling, prototyping, and communication. Success requires attention in lectures, studying documentation, and attendance to learn skills needed for engineering design in their career.
research methodology .pptgvbbbxxxxbnnnnncdTemesgenErena
This document provides an introduction to research methodology. It discusses what research is, the reasons for conducting research, and important characteristics of research such as being systematic, logical, empirical, objective, replicable, and transmittable. The document outlines the main steps in conducting research including choosing a subject, conducting a literature review, defining objectives, designing experiments, collecting and analyzing data, discussing and reporting results. It also discusses different types of research, writing research reports and proposals, and research ethics.
This document discusses three methods of heat transfer: conduction, convection, and radiation. Conduction involves the transfer of heat through direct contact of particles vibrating and transferring energy. Convection involves the transfer of heat by fluid movement as warmer materials rise and cooler materials sink. Radiation involves the transfer of heat through electromagnetic waves and does not require direct contact or the movement of particles.
The document discusses mechanical properties of materials and how they are tested and analyzed. It describes three main types of stresses - tensile, compressive, and shear - and how a stress-strain curve relates applied stress to the resulting strain in a material. Tensile tests are used to generate stress-strain curves and determine properties like elastic modulus, yield strength, tensile strength, and ductility. The curves have an elastic region and plastic region, and true stress-strain curves account for changes in cross-sectional area during deformation. Materials exhibit different categories of stress-strain behavior depending on properties like work hardening. Compression tests also measure stress-strain response under squeezing forces.
The document discusses toolmaking practices and tools. It describes several tools that toolmakers commonly use, including bench blocks, V-blocks, hammers, dial indicators, and clamps. It also discusses hand finishing and polishing techniques like using abrasive sticks, files, and mounted wheels. The document then covers electrodischarge machining (EDM) and how it can be used to machine dies and molds, including complex shapes. Finally, it briefly mentions tracer and duplicating mills for machining cavities based on a master pattern.
This chapter discusses different types of geometric modeling used in 3D design including wireframe modeling, surface modeling, and solid modeling. It introduces basic graphic elements, coordinate systems, and element construction. The objectives are for students to become familiar with using graphic elements, explaining coordinate systems, executing basic element and geometry construction, and learning how to manipulate wireframe, surface, and solid modeling techniques.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
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How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
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2. 2.1 Introduction
The cycle experienced in the cylinder of an internal combustion engine is
very complex.
First, air (CI engine) or air mixed with fuel (SI engine) is ingested and
mixed with the slight amount of exhaust residual remaining from the
previous cycle.
This mixture is then compressed and combusted, changing the composition
to exhaust products consisting largely of CO2, H20, and N2 with many other
lesser components.
3. Con…………
Then, after an expansion process, the exhaust valve is opened and this gas
mixture is expelled to the surroundings.
Thus, it is an open cycle with changing composition, a difficult system to
analyze.
To make the analysis of the engine cycle much more manageable, the real
cycle is approximated with an ideal air-standard cycle.
4. Con…………
The Three Thermodynamic Analysis of IC Engines are
I. Ideal Gas Cycle (Air Standard Cycle)
Idealized processes
Idealize working Fluid
II. Fuel-Air Cycle
Idealized Processes
Accurate Working Fluid Model
III. Actual Engine Cycle
Accurate Models of Processes
Accurate Working Fluid Model
5. Con…......
The operating cycle of an IC engine can be broken down into a sequence
of separate processes
Intake, Compression, Expansion and Exhaust.
The accurate analysis of IC engine processes is very complicated, to
understand it well, it is advantageous to analyze the performance of an
Idealized closed cycle.
6. 2.2 Air Standard Cycles
Air-Standard cycle differs from the actual by the following
1. The gas mixture in the cylinder is treated as air for the entire cycle, and
property values of air are used in the analysis.
2. The real open cycle is changed into a closed cycle by assuming that the
gases being exhausted are fed back into the intake system.
3. The combustion process is replaced with a heat addition term Qin of
equal energy value
7. Con………
4. Actual engine processes are approximated with ideal processes
a. The almost-constant-pressure intake and exhaust strokes are assumed to be
constant pressure.
b. Compression strokes and expansion strokes are approximated by isentropic
processes
c. The combustion process is idealized by a constant-volume process (SI cycle),
a constant-pressure process (CI cycle), or a combination of both (CI Dual
cycle).
d. Exhaust blow down is approximated by a constant-volume process.
e. All processes are considered reversible
8. Con………
In air-standard cycles, air is considered an ideal gas such that the following
ideal gas relationships can be used:
9. Isentropic Process
Isentropic process is a special case of an adiabatic process in which there
is no transfer of heat or matter.
For an ideal gas k is constant.
Using the equation of state for an ideal gas
10. Air Properties
For thermodynamic analysis the specific heats of air can be treated as functions of
temperature, which they are, or they can be treated as constants, which simplifies
calculations at a slight loss of accuracy.
Because of the high temperatures and large temperature range experienced during
an engine cycle, the specific heats and ratio of specific heats k do vary by a fair
amount.
At the low-temperature end of a cycle during intake and start of compression, a
value of k = 1.4 is correct. However, at the end of combustion the temperature has
risen such that k = 1.3 would be more accurate.
11. 2.2.1 Otto Cycle
The Otto cycle is one of the most common thermodynamic cycles found in
automobile engines and describes the functioning of a typical Spark
Ignition Engine.
A typical gasoline automotive engine operates at around 25% to 30% of
thermal efficiency.
12. Con………..
Intake Stroke
Starts with the piston at TDC
Constant pressure process at the inlet
pressure of one atmosphere.
In real engine process 0-1 will be slightly less
than atmospheric due to pressure losses in the
inlet air flow.
The temperature of the air during the inlet
stroke is increased as the air passes through
the hot intake manifold.
13. Con………..
Compression Stroke
It is an isentropic compression from BDC to TDC
(process 1-2)
(Isentropic process is a special case of an adiabatic process in which there is no
transfer of heat or matter.)
In real engine, the beginning of the stroke is affected by
the intake valve not being fully closed until slightly
after BDC.
The end of compression is affected by the firing of the
sparkplug before TDC.
In addition to increase in pressure there is also increase
in temperature due to compressive heating
14. Con………..
Combustion Process
It is a constant-volume heat input process 2-3 at
TDC while the piston is at rest at the top dead
center.
In real engines combustion starts slightly bTDC,
reaches its maximum speed near TDC, is
terminated a little aTDC.
Peak cycle pressure and temperature is reached at
point 3 due to energy added to the air within the
cylinder.
15. Con………..
Power (Expansion) Stroke
The gas expands adiabatically from state 3 to
state 4 as the piston moves from top dead
center to bottom dead center.
The power stroke of the real engine cycle is
approximated with an isentropic process in the
Otto cycle.
Values of both the temperature and pressure
within the cylinder decrease as volume
increases from TDC to BDC.
16. Con………..
Exhaust Blowdown
Exhaust valve is opened near the end of the power
stroke
A large amount of exhaust gas is expelled from the
cylinder, reducing the pressure to that of the exhaust
manifold
The exhaust valve is opened bBDC to allow for the
finite time of blowdown to occur.
The Otto cycle replaces the exhaust blowdown open-
system process of the real cycle with a constant–
volume pressure reduction, closed-system process.
17. Con………..
Exhaust Stroke
Occurs as the piston travels from BDC to
TDC.
Process 5-6 is the exhaust stroke that occurs
at a constant pressure of one atmosphere
due to the open exhaust valve.
18. Con………
Point 0 to 1 - Constant Pressure Intake
Point 1 to 2 - Isentropic Compression
Point 2 to 3 - Constant Volume Heat Input
Point 3 to 4 - Isentropic Expansion
Point 4 to 1 - Blow Down
Point 1 to 0 - Exhaust
Otto Cycle
19. Closing Thoughts on Otto Cycle
The Otto-cycle efficiency serves as an upper limit to the efficiency of
SI engines.
In practice this efficiency is never achieved.
This theoretical analysis is flawed in that it ignores friction and heat
transfer.
20. 2.2.2 Diesel Cycle
Fuel is injected into the combustion chamber very late in the compression
stroke.
Due to ignition delay and the finite time required to inject the fuel,
combustion lasted into the expansion stroke
This keeps the pressure at peak levels well past TDC.
Combustion process is approximated as constant-pressure heat input in an
air standard cycle
21. con………
Point 0 to 1 - Constant Pressure Intake
Point 1 to 2 - Isentropic Compression
Point 2 to 3 - Constant Pressure Heat Input
Point 3 to 4 - Isentropic Expansion
Point 4 to 1 - Blow Down
Point 1 to 0 - Exhaust
Diesel Cycle
22. Cut of ratio
Cut of Ratio (β): The change in volume that occurs during combustion, given
as a ratio.
23. Con………….
Thermal efficiency of Diesel Cycle
Note: the term in the square bracket is always larger than unity so for the same
compression ratio the Diesel cycle has a lower thermal efficiency than the Otto
cycle
24. 2.2.3 Dual Cycle
Fuel is injected earlier in the compression stroke, around 20 deg bTDC
Some of the combustion occurs almost at constant volume at TDC similar
to Otto Cycle
The fuel is being injected at TDC, and combustion of this fuel keeps the
pressure high into the expansion stroke.
The heat input process of combustion is approximated by a dual process of
constant volume followed by constant pressure.
26. Comparison of Otto, Diesel, and Dual Cycles
For the same inlet conditions, the same
compression ratios and same heat removal:
27. Con………
For the same inlet conditions, the same
peak pressure and same heat removal :
28. 2.3 Fuel-Air Cycle
The theoretical cycle based on the actual properties of the cylinder contents
is called the fuel air cycle.
The fuel air cycle take the following into consideration:
1. The actual composition of the cylinder contents.
2. The variation in the specific heat of the gases in the cylinder.
3. The dissociation effect.
29. Con………..
4. Compression & expansion processes are frictionless
5. No chemical changes in either fuel or air prior to combustion.
6. Combustion takes place instantaneously at top dead center.
7. All processes are adiabatic.
8. The fuel is mixed well with air.
30. Composition of Cylinder Gases
The composition of the working fluid, which changes during the engine
operating cycle, is indicated in the following table:
31. Variable Specific Heats
All gases except mono-atomic gases, show an increase in specific heat with
temperature. The increase in specific heat does not follow any particular law.
However between the temperature range 300 K – 1500 K the specific heat curve
is nearly a straight line.
Above 1500 K the specific heat increases is much more rapid and may be
expressed in the form
32. Con……….
Since the difference between Cp & Cv is constant, the value of k decreases
with increase in temperature
Thus, if the variation of specific heats is taken in to account during the
compression stroke, the final temperature and pressure would be lower
compared to the value obtained at constant specific heat.
33. Loss Due to Variable Specific Heats
The magnitude of drop of temperature at the end of compression is
proportional to the drop in values of ratio of specific heats.
34. Dissociation
The effect of dissociation
Dissociation is the disintegration of combustion products, at high
temperature above 1600K.
Dissociation is the reverse process to combustion
Dissociation is the heat absorption (endothermic process)
Combustion is heat liberation (Exothermic process)
In IC engine, mainly dissociation of CO2 and little dissociation of H20
36. Con……….
There is no dissociation in the burnt gases of a lean fuel-air mixture. This
mainly due to the fact that the temperature produced is too low for this
phenomenon to occur.
The maximum dissociation occurs in the burnt gases of the chemically
correct fuel-air mixture when the temperature are expected to be high but
decreases with the leaner and richer mixtures.
37. The Effect of Dissociation
On Exhaust Gas Temperature, the
Figure shows the reduction in the
temperature of the exhaust gas mixtures
due to dissociation w.r.t air fuel ratio.
38. The Effect of Dissociation
On the p-v diagram of Otto Cycle
Because of lower maximum
temperature due to dissociation. The
maximum pressure is also reduced
and state after combustion will be
replaced by 3’ instead of 3.
39. 2.4 The Actual Cycle
The actual cycle experienced by internal combustion engines is an open
cycle with changing composition, actual cycle efficiency is much lower
than the air standard efficiency due to various losses occurring in the actual
engine.
40. Con………
These losses are as follows:
1. Losses due to variation of specific
heats with temperature
2. Losses due to dissociation.
3. Time losses, effect of spark timing
4. Incomplete combustion loss.
5. Direct heat loss.
6. Exhaust blow down loss.
7. Pumping losses.
8. Friction losses.
9. Effect of throttle opening
