CFD STUDY OF PROSPECTIVE 1ST STAGE CENTRIFUGAL IMPELLER DESIGN

摘要

CFD analysis of two first - stage centrifugal impellers is undertaken with the main goal to obtain additional evaluation data regarding flow characteristics of the old first stage impeller design and in the proposed new cantilever impeller design. The new design is developed to reduce the 1st stage impeller cavitation erosion damage of a multistage centrifugal feed pump. This stage of work comprises computational tests of both impeller models under the same mode of operation, 3000 RPM and volumetric flow rate 0.0503 m{sup}3/s. Both impellers are planning to be tested experimentally. The inlet geometry for CFD tests is taken from the test facility draft. The outlet is made like a circular vaneless diffuser. In the old design, a hub developed upstream presents the through shaft. Computational results are compared with the head/efficiency data delivered by plane cascade theory. Computational data shows an advantage of the new design by head and efficiency although the efficiency level is underestimated. Computational data shows lower pressure zones in the proposed design are localized at the impeller inlet periphery, in the old design lower pressure zones spreads along the blade inlet height. Further computational test will be made for the whole geometry including the stage stator part and experimental validation of the proposed design will follow.