Entropy isentropic processes

Cp/Cy for a constant-entropy (isentropic) process in an ideal gas of constant heat capacity... 

The fact that shock waves continue to steepen until dissipative mechanisms take over means that entropy is generated by the conversion of mechanical energy to heat, so the process is irreversible. By contrast, in a fluid, rarefactions do not usually involve significant energy dissipation, so they can be regarded as reversible, or isentropic, processes. There are circumstances, however, such as in materials with elastic-plastic response, in which plastic deformation during the release process dissipates energy in an irreversible fashion, and the expansion wave is therefore not isentropic. 

During process 1-2, the system is thermally insulated and the temperature of the working substance is raised from the low temperature Tl to the high temperature T-. The process is an isentropic process. The amount of heat transfer during the process is = J TAS = d, because there is no area underneath a constant entropy (vertical) line. 

ADIABATIC PROCESS. Any thermodynamic process, reversible or irreversible, which takes place in a system without the exchange of heat with the surroundings. When the process is also reversible, it is called isentropic, because, then the entropy of the system remains constant at every step of the process, fin older usage, isentropic processes were called simply adiabatic, or quasistatic adiabatic the distinction between adiabatic and isentropic processes was not always sharply drawn.)... 

Other specifications for the product, such as pressure and heat duty (e.g., adiabatic processes) or pressure and entropy (e.g., isentropic processes) also involve finding the extremum of a thermodynamic function. Given pressure and heat duty, the entropy is maximized... 

International Practical Temperature Scale, 5-6 Irreversibility, 40-41, 554-555 and entropy changes, 155-157, 554 Isentropic process, 153-155, 187-189, 223-231, 235-240... 

When dQ is zero, then T dS must be zero, and since we know we did not carry out this process at absolute zero, dS must be zero. This means that during the process, the entropy must have remained constant—aha —an isentropic process. So the path of the changes in our state variables P,v must be along an isentrope. This means that Eq. 19.1 becomes... 

In a reversible, adiabatic, i.e., isentropic, process, the entropy remains constant, and hence AS should be zero the condition for a reversible, adiabatic process can thus be obtained by setting equation (19.21) equal to zero. The result is... 

VELOCITY OF SOUND. The velocity of sound through a continuous material medium, also called the acoustical velocity, is the velocity of a very small compression-rarefaction wave moving adiabatically and frictionlessly through the medium. Thermodynamically, the motion of a sound wave is a constant-entropy, or isentropic, process. The magnitude of the acoustical velocity in any medium is... 

Isentropic process - A thermodynamic process in which the entropy of the system does not change. 

We may readily find Eq. 9.15 by substituting the relation for an isentropic process for a perfect gas in Eq. 4.40. We may find Eq. 9.13 by substituting the isothermal relation for a perfect gas in Eq. 4.40 and using the entropy balance to solve for dQldm (Prob. 9.24). Thus, we may find exactly the same results by a mechanical view of what happens inside the compressor or by a thermodynamic view of the compressor as the system from the outside. 

This is true for any substance— solid, liquid, or gas.) For a constant-entropy process (i.e., an isentropic process), the first term on the right of the equals sign is zero. We then substitute for dh from Eq, D.3 and substitute for Cp from Eq. D.IO to find... 

ISENTROPIC PROCESS - A process carried out reversibly without energy interchange as heat. Also a processes carried out with no entropy change. 

The TS plane offers yet another way of representing the thermodynamic state of a system. On this plane, isotherms are shown by horizontal lines, while vertical lines represent lines of constant entropy (isentropic lines). Along an isentropic line, dS = o according to eg. (d.i). this condition is met if a process is a mechanically reversible adiabatic process. Thus we conclude that a reversible adiabatic process is also isentropic. 

The entropy of ideal gas is given in eg. (d.22). For an isentropic process, AS s = o. Applying this condition to eg. fd.22) we obtain a relationship between pressure and temperature along the isentropic path ... 

Isentropic process Any process that takes place without a change of entropy. The quantity of heat transferred, 5Q, in a reversible process is proportional to the change in entropy, 5S, i.e. 5Q= 7SS, where T is the thermodynamic temperature. Therefore, a reversible adiabatic process is isentropic, i.e. when 5Q equals zero, 5S also equals zero. 

An ideal compressor is an isentropic process (i.e. the change in entropy of the stream is zero). A simple schematic of a compression process is shown in Figure 2. The specification for a compressor is the inlet temperature and pressure and the outlet pressure (or equivalently the compression ratio). For the ideal case ... 

The significance of flash fractions is that they give the maximum possible vapor fraction formed in an isentropic process for discharges into the atmosphere. This statement could be derived mathematically starting from Eq. (27.7) and equations for the temperature dependency of the vapor and liquid entropies in saturated state. For instance, in choked isentropic pipe flow the vapor fraction of the fluid at the aperture is always smaller than the flash fraction (because the exit pressure is higher than the atmospheric pressure). 

Isentropic processes can be analyzed by determining the reference entropy. Because of the frequency of its use for air, isentropic processes can also be analyzed using the relationships. 

Isentropic process A reversisble and adiabatic or a constant entropy process. 

It states that entropy increases in a process with heat addition to the system and decreases for a process with heat rejection from the system. For a reversible and adiabatic process, also known as isentropic process, there is no heat transfer and entropy remains constant that is. 

Isentropic process A process without a change in entropy. See also Entropy. 

For an isentropic process (i.e a process in which there is no change in entropy), direct integration of this expression provides... 

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