isentropic process

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Isentropic process

In thermodynamics, a process involving change without any increase or decrease of entropy. Since the entropy always increases in a spontaneous process, one must consider reversible or quasistatic processes. During a reversible process the quantity of heat transferred is directly proportional to the system's entropy change. Systems which are thermally insulated from their surroundings undergo processes without any heat transfer; such processes are called adiabatic. Thus during an isentropic process there are no dissipative effects and the system neither absorbs nor gives off heat. For this reason the isentropic process is sometimes called the reversible adiabatic process. See Adiabatic process, Entropy, Thermodynamic processes

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.

isentropic process

[¦īs·ən′träp·ik ′prä·ses]
A change that takes place without any increase or decrease in entropy, such as a process which is both reversible and adiabatic.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
At standard temperature and pressure conditions, the bulk modulus [B.sub.o] of air is 1.42 x [10.sup.5] Pa for an isentropic process. Suppose that I = 20.0 mm, S = 225 [pi][mm.sup.2], [R.sub.o] = 5.0 mm, [R.sub.i] = 4.5 mm, and a = 0.5 mm to 2.5 mm (Figure 1(b)).
This paper gives an in-depth analysis of descriptive functionality of PLAM index, explores contributions of relevant PLAM sensitive parameters in the relatively "static and stable" isentropic processes, and investigates impacts of the height of pollution mixing layer and vertical atmospheric structure upon the local aerosol density variations.
The Assumption of Local Isentropic Process. The flow behind the detonation front of aluminized explosive cannot be treated as an isentropic process approximately due to the chemical reaction of Al particles in the detonation products.
Then it is depressurized through the expansion valve with an isentropic process. The s-C[O.sub.2] flow leaving the expansion valve will enter the heat exchanger and be cooled by the secondary water flow.
Supposing an isentropic process in the expander, the leaving velocity [V.sub.2i] can be calculated by
The fluid remaining in the clearance volume undergoes again an isentropic process until state D is reached, where the pressure differential at the inlet causes the suction valves to open.
where subscript "" refers to the outlet state corresponding to the isentropic process between the operational inlet and outlet pressures, and [[eta].sub.P] denotes the isentropic efficiency of the pump.
Compressor performance is characterized by its isentropic efficiency which is work from an ideal or isentropic process divided by actual work Equation (5).
Then, the temperature in the first-stage and second-stage mufflers are estimated by assuming an isentropic process:
* Process 4-5: The saturated vapor expands through a turbine to generate power output (ideally an isentropic process).
The compressor and turbine were modeled as isentropic processes discounted by efficiencies of 77% and 71%, respectively.
In classical theory all thermodynamic processes are reversible and adiabatic, known as an isentropic processes. The small parameter expansion is carried out with a fixed density [[rho].sub.0] of the fluid (SI unit: kg/[m.sup.3]) and pressure [[rho].sub.0] (SI unit: Pa) such that: