ABSTRACT
In view of the impossibility of obtaining exact solutions for three-dimensional gas flow in jet engines (JE) the necessity to use hydraulic approximation for such flows arises, that is, to seek flow parameters, averaged with respect to the channel cross section, chosen in a proper way. Additionally, even in those cases when the 3-D flows in separate JE units (diffuser, compressor, combustion chamber, turbine, propulsive nozzle) are calculated, the relation between these units for the analysis of engine performance is established hydraulically, according to mean values of gas parameters. The aim of correct averaging is to describe a non-uniform gas flow by means of the least number of parameters that occurred in the flow earlier or are important for further use of the flow in the technical problem under consideration. Characteristics of engine test beds for gas-turbine engines and compressors and the methods of experimental investigation are defined by the requirements of the preservation of similarity conditions.
