What are cold air standard assumptions?
These assumptions are: (1)The working fluid is air, which continuously circulates in a closed loop and always behaves as an ideal gas. (2)All the processes are internally reversible. (3)The combustion process is replaced by a heat addition process. (4)The exhaust process is replaced by a heat rejection process.
What are the assumptions of an air standard analysis cold air standard analysis?
9-6C The air standard assumptions are: (1) the working fluid is air which behaves as an ideal gas, (2) all the processes are internally reversible, (3) the combustion process is replaced by the heat addition process, and (4) the exhaust process is replaced by the heat rejection process which returns the working fluid …
What is the value of working fluid in Otto cycle?
What is the value of working fluid in otto cycle? Explanation: In air standard otto cycle working fluid is air. The specific heat ratio of air is equal to 1.4.
Is the Otto cycle reversible?
The Otto cycle is another example of a reversible cycle that only exists in theory. The first process in the Otto cycle is an adiabatic compression, which decreases the volu me and increases the pressure. No heat flows into or out of the system during this process but work is done by the surroundings on the system.
What is the efficiency of Otto cycle?
Efficiency is the proportion of the work and the supplied heat. For a cyclic process, the change in the total internal energy of the gas during one cycle is zero.
Is a Carnot cycle reversible?
The Carnot heat-engine cycle described is a totally reversible cycle. That is all the processes that compose it can be reversed, in which case it becomes the Carnot refrigeration cycle.
Why is Carnot cycle most efficient?
The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws. This means that the Carnot cycle is an idealization, since no real engine processes are reversible and all real physical processes involve some increase in entropy.
Is Carnot cycle possible?
The Carnot cycle is a theoretical cycle that is the most efficient cyclical process possible. Any engine using the Carnot cycle, which uses only reversible processes (adiabatic and isothermal), is known as a Carnot engine. Any engine that uses the Carnot cycle enjoys the maximum theoretical efficiency.
Where is Carnot cycle used?
Carnot cycle, in heat engines, ideal cyclical sequence of changes of pressures and temperatures of a fluid, such as a gas used in an engine, conceived early in the 19th century by the French engineer Sadi Carnot. It is used as a standard of performance of all heat engines operating between a high and a low temperature.
What is Carnot cycle with diagram?
The Carnot cycle consists of the following four processes: A reversible isothermal gas expansion process. In this process, the ideal gas in the system absorbs qin amount heat from a heat source at a high temperature Thigh, expands and does work on surroundings….T-S Diagram.
| Process | ΔT | ΔS |
|---|---|---|
| IV | Thigh−Tlow | 0 |
| Full Cycle | 0 | 0 |
What is the efficiency of Carnot cycle?
It is well known that the Carnot cycle efficiency ( η thermal = 1 − T L T H ) is maximized with the highest possible heat source temperature TH and the lowest possible heat sink temperature TL.
What is cycle efficiency?
Definition: Cycle Efficiency, often-abbreviated CE, is a ratio that measures the effectiveness and productivity of the production process by comparing the value added time with the total production time. In other words, it’s a calculation that cost accountants use to measure how efficiently products are being produced.
What are the four process of Carnot cycle?
Name the processes involved in Carnot cycle? It involves four process: isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression.
What is Carnot cycle explain?
: an ideal reversible closed thermodynamic cycle in which the working substance goes through the four successive operations of isothermal expansion to a desired point, adiabatic expansion to a desired point, isothermal compression, and adiabatic compression back to its initial state.
How is Carnot cycle calculated?
W=QH−QC=(1−TCTH)QH. efficiency =WQH=1−TCTH. These temperatures are of course in degrees Kelvin, so for example the efficiency of a Carnot engine having a hot reservoir of boiling water and a cold reservoir ice cold water will be 1−(273/373)=0.27, just over a quarter of the heat energy is transformed into useful work.
What is S in TS diagram?
A temperature–entropy diagram, or T–s diagram, is a thermodynamic diagram used in thermodynamics to visualize changes to temperature and specific entropy during a thermodynamic process or cycle as the graph of a curve. Working fluids are often categorized on the basis of the shape of their T–s diagram.
What is PV and TS diagram?
As described on the work slide, the area under a process curve on a p-V diagram is equal to the work performed by a gas during the process. On the right of the figure we have plotted the temperature versus the entropy of the gas. This plot is called a T-s diagram.
What is the importance of TS diagram?
A Temperature-entropy diagram (T-s diagram) is the type of diagram most frequently used to analyze energy transfer system cycles. It is used in thermodynamics to visualize changes to temperature and specific entropy during a thermodynamic process or cycle.
What is SI unit of entropy?
Entropy is a function of the state of a thermodynamic system. It is a size-extensive quantity, invariably denoted by S, with dimension energy divided by absolute temperature (SI unit: joule/K).
Why is entropy not conserved?
Entropy is not a conserved quantity: for example, in an isolated system with non-uniform temperature, heat might irreversibly flow and the temperature become more uniform such that entropy increases. The second law of thermodynamics states that a closed system has entropy that may increase or otherwise remain constant.
Can entropy be negative?
There is no such thing as negative entropy, but a negative change in entropy exists. For example, a reaction that condenses from a gas to liquid would have a negative delta S because the liquid would occupy less possible states than the gas due to the decrease in temperature and volume.
Why is entropy S?
Explanation: It is generally believed that Rudolf Clausius chose the symbol “S” to denote entropy in honour of the French physicist Nicolas Sadi-Carnot. His 1824 research paper was studied by Clausius over many years.
What is entropy explain with example?
Entropy is a measure of the energy dispersal in the system. We see evidence that the universe tends toward highest entropy many places in our lives. A campfire is an example of entropy. The solid wood burns and becomes ash, smoke and gases, all of which spread energy outwards more easily than the solid fuel.
How is entropy related to energy?
Temperature is the change in energy due to the change in entropy. And since there is no negative sign, it is phrased as a positive — energy increases when entropy is added. For a fixed temperature, if you double the entropy, the energy doubles also.
Who named entropy?
Rudolf Clausius
Is entropy good or bad?
In general entropy is neither good nor bad. There are many things that only happen when entropy increase, and a whole lot of them, including some of the chemical reactions needed to sustain life, would be considered as good. That likely means that entropy as such is not nearly always a bad thing.
Why is entropy measured in J K?
The Measure of Entropy If I add an amount of energy ΔE (measured in Joules, say), to a system at temperature T (measured on an absolute scale, like Kelvin), the entropy changes according to ΔS = ΔE/T. The units are Joules per Kelvin. This is very closely related to the heat capacity of a system or object.