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A process during which the entropy remains constant is called an isentropic process, written = or =. [12] Some examples of theoretically isentropic thermodynamic devices are pumps, gas compressors, turbines, nozzles, and diffusers.
isentropic process – the heated, pressurized air then gives up its energy, expanding through a turbine (or series of turbines). Some of the work extracted by the turbine is used to drive the compressor. isobaric process – heat rejection (in the atmosphere). Actual Brayton cycle: adiabatic process – compression; isobaric process – heat ...
In an ideal Rankine cycle the pump and turbine would be isentropic: i.e., the pump and turbine would generate no entropy and would hence maximize the net work output. Processes 1–2 and 3–4 would be represented by vertical lines on the T–s diagram and more closely resemble that of the Carnot cycle.
Most turbo machines are efficient to a certain degree and can be approximated to undergo isentropic process in the stage. Hence from =, Figure 1. Enthalpy vs. Entropy diagram for stage flow in turbine. it is easy to see that for isentropic process ∆H ≃ ∆P.
Because work is extracted from the expanding high-pressure gas, the expansion is approximated by an isentropic process (i.e., a constant-entropy process), and the low-pressure exhaust gas from the turbine is at a very low temperature, −150 °C or less, depending upon the operating pressure and gas properties. Partial liquefaction of the ...
An isentropic process is customarily defined as an idealized quasi-static reversible adiabatic process, of transfer of energy as work. Otherwise, for a constant-entropy process, if work is done irreversibly, heat transfer is necessary, so that the process is not adiabatic, and an accurate artificial control mechanism is necessary; such is ...
Adiabatic : No energy transfer as heat during that part of the cycle (=). Energy transfer is considered as work done by the system only. Isothermal : The process is at a constant temperature during that part of the cycle (=, =). Energy transfer is considered as heat removed from or work done by the system.
Isentropic is the combination of the Greek word "iso" (which means - same) and entropy. When the change in flow variables is small and gradual, isentropic flows occur. The generation of sound waves is an isentropic process. A supersonic flow that is turned while there is an increase in flow area is also isentropic.