Processes of Compressible Flow

The individual processes to be considered in this chapter are shown diagrammatic-ally in Fig. 6.1. It is assumed that a very large supply of gas at specified temperature and pressure and at zero velocity and Mach number is available. The origin of the gas is called the reservoir, and the temperature and pressure of the gas in the 

From the reservoir the gas is assumed to flow, without friction loss at the entrance, into and through a conduit. The gas leaves the conduit at definite temperature, velocity, and pressure and goes into an exhaust receiver, in which the pressure may be independently controlled at a constant value less than the reservoir pressure. 

An isentropic expansion. In this process the cross-sectional area of the conduit must change, and the process is described as one of variable area. Because the process is adiabatic, the stagnation temperature does not change in the conduit. Such a process is shown diagrammatically in Fig. 6.1a. 

Adiabatic frictional flow through a conduit of constant cross section. This process is irreversible, and the entropy of the gas increases, but as shown by Eq. (6.22), since Q 0, the stagnation temperature is constant throughout the conduit. This process is shown in Fig. 6.1b. 

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