Prediction of off design performance of multistage compressors
A new method for predicting the off design performance of a multistage compressor has been developed. This method replaces the usual routine numerical integration through the compressor by approximate analytical integration. The overall compressor performance of the compressor is found as a perturba...
Summary: | A new method for predicting the off design performance of a multistage compressor has been developed. This method replaces the usual routine numerical integration through the compressor by approximate analytical integration. The overall compressor performance of the compressor is found as a perturbation of the design performance in terms of linear and quadratic expansions in two parameters, the deviation from the design flow rate and the deviation from the design speed. The procedure for this preliminary examination has been simplified by assuming that all the single stage performance characteristics are identical and that the difference between static and stagnation conditions are negligible.
The results of this method are quadratic equations, in terms of the two perturbation parameters, for the temperature ratio, pressure ratio and adiabatic efficiency of the overall compressor. The amount of numerical work in finding the coefficients of these quadratic expansions is not negligible, however the method appears promising. Reasonably accurate results are expected for speeds varying as much as ten per cent from design and flow rates varying as much as four per cent from the design flow. |
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