NUMERICAL ANALYSES OF FLOW FIELDS IN A VANED DIFFUSER WITH VARIOUS FLOW RATES
作者单位：School of Mechanical Engineering SungKyunKwan University 300 Cheoncheon-dong Suwon 400-746 Korea School of Mechanical Engineering SungKyunKwan University 300 Cheoncheon-dong Suwon 400-746 Korea School of Mechanical Engineering SungKyunKwan University 300 Cheoncheon-dong Suwon 400-746 Korea
会议名称：《第一届亚洲制冷空调大会》
会议日期：2002年
学科分类：080704[工学-流体机械及工程] 08[工学] 0807[工学-动力工程及工程热物理]
关 键 词：Turbo-compressor Vaned and vaneless diffusers Loss coefficient Pressure recovery coefficient
摘 要：正The optimal design of the elements, i.e., impeller, diffuser, and casing in a turbo-compressor is very important, because the dynamic energy developed by the impeller transformed into the pressure energy in the diffuser and casing. The performance characteristics of the diffuser are complicated with different geometric shapes. To improve the performance of the small-size turbo compressor with a high rotating speed, the effects of flow rates from 0.8 times design point to 1.2 times Qd are numerically studied. Also, the comparison of the performance of the vaneless and vaned diffusers carried out. A blade of an impeller has two-dimensional backswept shape to avoid the tip clearance effects. In order to predict the flow pattern inside the entire impeller, diffuser and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. All domains for analyses are discretized by bexahedral elements. Three-dimensional, unsteady, viscous governing equations are solved using FVM, SIMPLE algorithm, and κ-εturbulence model. The pressure recovery coefficient （Cp） and the loss coefficient （K） have been calculated to estimate the performance and loss of the diffuser. Furthermore, the magnitude of velocity and the distributions of static and total pressures are calculated along the length of the diffuser.