INVESTIGATION OF EFFECTS OF REYNOLDS NUMBER ON LARGE DOUBLE-ENTRY CENTRIFUGAL COMPRESSOR

摘要

An investigation was conducted on a large-capacity double-entry-centrifugal compressor to determine the .effects of Reynolds number on over-all performance and also to obtain some idea of the origin and nature of the effects. The compressor was operated over a range of inlet conditions equivalent to pressure altitudes of 20,000 to 50,000 feet at equivalent tip speeds of 916, 1309, and 1545 feet per second.nThe decreases in the parameters affecting over-all performance at design speed (tip speed of 1545 ft/sec) for a change in pressure altitude from 20,000 to 50,000 feet were:(l) peak total-pressure ratio, 3.4 percent, (2) maximum equivalent weight flow, 3.8 percent, and (3) peak efficiency, 0.02. The origin of at least part of the Reynolds number effects in this compressor is in the inlet and the inducer sections. In the case of a double-entry impeller, the Reynolds number affects not only the matching of the impeller and the diffuser but also the matching of the front and the rear impellers.