Compound-compressible nozzle flow

A one dimensional theory based upon fundamental flow relationships is presented for analyzing the behavior of one or more gas streams flowing through a single nozzle. This compound compressible flow theory shows that the behavior of each stream is infuenced by the presence of the other streams. The behavior of compound compressible flow is predicted by determining how changing conditions at the nozzle exit plane affect conditions within the nozzle. When choking of the compound compressible flow nozzle occurs, an interesting phenomenon exists. The compound compressible flow is shown to be choked at the nozzle throat, although the individual stream Mach numbers there are not equal to one. This phenomenon is verified by a wave analysis which shows that, when choking occurs, a pressure wave cannot be propagated upstream to the nozzle throat even though some of the individual streams have Mach numbers less than one. Algebraic methods based on this compound compressible flow theory are used to demonstrate the usefulness of this approach in computing the behavior of compound-compressible flow nozzles.