Instrumentation Selection and Uncertainty Analysis for Performance Test of Small Centrifugal Compressors

Abstract

In the design phase of centrifugal compressors, it is essential to have some experimental results on performance. The extent of usefulness of the experiments depends on quality and accuracy of the results. Part of proper experimental procedure is the correct selection of instrumentation leading to lower uncertainty in the final results. ASME PTC 10 (Performance Test Code on Compressors and Exhausters) requires fluctuation limits on the measured performance parameters. This does not guarantee limits for accuracy of performance parameters. Also, different experimental setup will affect uncertainty of the results, even with similar instrumentation accuracy. The present research deals with uncertainty analysis for performance evaluation of small-scale centrifugal compressor. The instrumentation errors are accommodated in the relation to ASME PTC 19.1 (test uncertainty). The analysis takes into consideration the correlated bias limits. Selection of proper type of instruments for measuring associated parameters is based on literature review. A case study is included as an example to illustrate the selection on instrumentation accuracy and preferred bias correlations. The analysis is a useful tool in designing experiments for testing compressor and optimizing accuracy of results.