Compressor Performance Verification: Measuring Tolerances and Guaranteed Power Consumption

When evaluating the power consumption of a compressor on a test bed, it is important to evaluate the inaccuracies caused by instruments measuring tolerances.Compressor vendors need to estimate such tolerances when announcing power guarantee figures, while customers need to verify if the machine meets such performance guarantees or not. A method is proposed to assess the resulting uncertainty of the total power consumption of a centrifugal compressor, based on the instruments measuring tolerances for inter-stage pressures, inter-stage temperatures and mass flow.The calculations are based on a Monte Carlo type simulation which generates random sets of inlet/outlet pressures and temperatures for the different compressor stages.Such numbers are generated in order to lie within the range of the expected value ± instrument tolerances. The same technique is used for the mass flow.A numerical example is given, in order to show how single instruments tolerances are cumulated; results may indicate which instrument to select (or discard) in order to obtain reasonable tolerances on the calculated power consumption.Copyright © 2013 by ASME