ESDU 74028:2007

ESDU 74028 gives curves and equations for use in the calculation of isentropic flow of a perfect gas; they are applicable to numerous practical situations. The curves are plotted for a range of ratios of specific heat capacities from 1 to 1.67 and for Mach numbers to unity. The equations can be applied to all Mach numbers provided no dissociation occurs. The conditions covered are 1. at a point in the flow, the ratio of static/total temperature, of static/total pressure, and of velocity/speed of sound in the gas brought isentropically to rest; 2. at a point in the flow, the ratios of kinetic/total pressure and of dynamic/kinetic pressure; 3. for the expansion of a gas through a nozzle with sonic flow at the throat, the ratio as a function of Mach number of the pressure, temperature and area at any point in the flow to the pressure, temperature and area respectively at the throat; 4. in the expansion from a reservoir, the ratio of density, temperature and velocity to the corresponding reservoir conditions as a function of pressure ratio and 5. three mass flow functions involving total pressure and temperature, total temperature but static pressure, and static pressure and temperature.