مهندسی مکانیک شریف (May 2017)
OPTIMUM DESIGN, FABRICATION, AND TEST OF A RADIAL FLOW COMPRESSOR VOLUTE
Abstract
Volute is one of the main components in radial flow compressors where the working fluid is collected and delivered to the compressor downstream pipelines. Volute design has direct and strong effects on the compressor performance and its stable operating range. This component causes distorted pressure fields in upstream flow passages which can lead to mechanical forces on the impeller. In the current research, based on the fundamental concepts of volute design, a new approach for volute design is considered and the effective parameters on volute performance are recognized. Using computational fluid dynamic (CFD) tools, the optimum values of effective parameters which lead to an increase in volute pressure ratio and static pressure recovery coefficient as well as decreasing the total pressure loss coefficient and the net radial force are explored.Considering the exit cone and the tongue area geometry design criteria, the models are numerically evaluated at the design point and off-design conditions to select the optimum model for fabrication and testing. The new volute is installed at a compressor test rig and the compressor characteristic curves are obtained. At the design point, area variation by 40\% results in 14\% variation in static pressure recovery factor and 18\% variation in total pressure loss coefficient, however, it leads to increase the net radial force on impeller up to 100\%. Experimental results, which are used for numerical model verification, show that the compressor pressure ratio and the isentropic efficiency are increased by 2.5\% and 1.9\% at 70,000rpm respectively.
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