Methods of surge point judgment for compressor experiments

Precise judgment of surge point is crucial for compressor performance experiments. Three types of dynamic measurements (pressure, temperature and acoustic noise) have been investigated to judge the surge points of compressor. Fast-response pressure and temperature probes are mounted at the impeller inlet and diffuser mid-section while microphones are set up in vicinity of the casing and duct inlet of a centrifugal compressor. Thus, typical forms of surge and signal features from different measuring tools are minutely discussed; some analysis are presented and connected with predecessors' researches on flow mechanism of stall or surge. Finally, an efficient criterion for surge point judgment has been concluded that the standard deviation of temperature signals have an abrupt rise-turn at the minimum flow rate limit. This new criterion has been verified in different types of centrifugal compressors, which can help judge surge point of compressors' performance map in a relatively accurate and quantitative way.