Why is Carnot cycle used as a standard of reference for steam power plants?

Why is Carnot cycle used as a standard of reference for steam power plant?

Carnot cycle has high specific steam consumption, large back work ratio and low work ratio. The steam at exhaust from the turbine is of low quality i.e., high moisture content. The liquid water droplets cause pitting and hence erosion of the turbine blades.

Why is the Carnot cycle utilized in large power plants?

The Carnot cycle is a theoretical power cycle and is used for showing the theoretical maximum of a heat engine. Both isothermal heat addition and rejection processes are very challenging to achieve, as they need large heat exchangers (HEXs) and very long heat transfer time.

Why is the Carnot cycle important?

The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws. When the second law of thermodynamics states that not all the supplied heat in a heat engine can be used to do work, the Carnot efficiency sets the limiting value on the fraction of the heat which can be so used.

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Why is Carnot cycle most efficient?

The Efficiency of Carnot’s Cycle

Practical engine cycles are irreversible and thus have inherently lower efficiency than the Carnot efficiency when operating at the same temperatures. … The Carnot cycle achieves maximum efficiency because all the heat is added to the working fluid at the maximum 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
Full Cycle

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 impractical in real situations?

Carnot cycles are not encountered in reality since achieving isothermal heat transfer is very difficult (needs very large heat exchangers and long time). Also process 3-4 requires a pump or compressor that can handle two phase mixture (liquid and vapor) which is impractical.

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 are the four 4 processes that made up the Carnot cycle?

Name the processes involved in Carnot cycle? It involves four process: isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression.

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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 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.

Is Carnot engine 100 efficient?

In order to achieve 100% efficiency (η=1), Q2 must be equal to 0 which means that all the heat form the source is converted to work. The temperature of sink means a negative temperature on the absolute scale at which the temperature is greater than unity.

Why is Carnot engine Impossible?

This is impossible to attain practically because isothermal is very slow and adiabatic is very fast. The heat exchange in carnot cycle is isothermal which needs the working fluid to either phase change or the process be extremely slow. Thus constant pressure process is used in rankine cycle.

Which Carnot engine is more efficient?

Irreversible engines

No irreversible engine is more efficient than the Carnot engine operating between the same two reservoirs.

Power generation