Effects of Measurement Errors on High Speed Compressor Performance R-2

摘要

Measurable and unknown errors in flow measurements especially in the sonic region are treated. On the basis of the instrument calibration a few errors are estimated and their effects on the performance parameters are evaluated. The single relative errors are not valid for all conditions because the errors depend on the parameter level and one has to choose some parameters numerically. Here errors are calculated for several Mach numbers and air percentages in the real flow. Further, the total pressure level of the settling chamber changes the errors. No general analyses of errors, based on the differentiation of the formulas, were made. For the special case of one test extreme errors are assumed and their influences are given numerically. It is shown that by the translation from the actual flow (Freon-air mixture) to a pure air flow the errors in some results increase and in other parameters decrease, dependent upon the different functions. The critical parameters are angles, static pressures, temperatures and air percentage. (Author)