Effects of diffuser phase angle on hydraulic performance of oil pipeline transportation pump
Tan Dongjie1,2, Bai Yu3, Liu Houlin3, Dong Liang3, Li Baisong1, Zhang Hong2
1.PetroChina Pipeline Research & Development Center, Langfang, Hebei 065000, China; 2.College of Mechanical and Transportation Engineering, China University of Petroleum(Beijing), Beijing 102249, China; 3.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract：In order to improve the hydraulic performance of oil pipeline transportation pump, a specific pump of this kind with high flow rate is used and the effects of diffuser phase angle on the performance are investigated. The 3D geometry of the whole fluid domain of the pump is generated in Pro/E and the domain is meshed in Gambit. The steady flow fields in the pump are simulated at 6 phase angles(0?, 6?, 12?, 18?, 24? and 30?)and under 5 operating conditions(0.8Qd, 0.9Qd, 1.0Qd, 1.1Qd and 1.2Qd)based on CFX. Consequently, the hydraulic performance curves at different phase angles are obtained and the flow fields are compared among different phase angles. The results show that the head differs from one angle to another significantly, causing a 6% maximum difference under design condition; however, the head at a high or low flow rate demonstrates a less variation between different phase angles. The pump efficiency shows a larger variation between different phase angles at a high or low flow rate, under the design condition, however, the efficiency varies as a little as 2%. The low velocity zone on the blade convex surface near the diffuser outlet is the important factor affecting the hydraulic performance of the pump. The flow field around the volute tongue is different from one diffuser phase angle to another, subsequently the pump hydraulic performance is affected. The flow pattern in the volute nozzle gets poorer at the phase angles of 6?, 12癮nd 18? under the influence of the low velocity zone. It is the low velocity zone that results in a lowered pump efficiency and a rather uneven fluid velocity distribution at the volute outlet, causing the pump is operated in a less stability and efficiency.
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