悬空高对泵装置流道内流特性的影响

Effect of Bottom Clearance on Flow Characteristics of Pumping System by CFD and PIV

采用单因素比较法对6种不同喇叭管悬空高的立式轴流泵装置进行了全流道的CFD数值计算和喇叭管中心区域的PIV流场测试,分析了不同方案各工况时箱涵式进水流道内附底涡的初生位置变化情况。结果表明:相同工况时附底涡初生位置因喇叭管悬空高的不同而改变;在相同喇叭管悬空高时涡核中心起始位置因工况的不同而改变;喇叭管悬空高度越低,喇叭管底部的速度梯度变化越剧烈。箱涵式进水流道的喇叭管悬空高度建议取0.8D(D为叶轮名义直径),宜在该类型的进水流道内设置消涡装置。数值计算和PIV流场测试获得的测试区流场的速度分布及附底涡核线轨迹基本相同。

Based on computational fluid dynamic （CFD） and particle image velocimetry （PIV） technology, factor analysis method was used to study the effect of bottom clearance of flare on the flow characteristics of pumping system, and the occurred location change of submerges vortex and the submerged vortex core trajectory were analyzed emphatically. The results show that the occurred location of submerges vortex change along with the change of bottom clearance of flare, and the occurred location of submerges vortex along with the change of operating condition in the same bottom clearance of flare. With the decrease of bottom clearance, the velocity gradient varies greatly in the zone of the flare bottom. The bottom clearance h = 0.8D was strongly suggested and the anti-submerged vortex device should be taken for this kind of box-type inlet passage. The velocity distribution contour of test section by PIV was similar to that by CFD, and the trajectory of submerged vortex by CFD was similar to that by PIV. It was also proved that the measured results showed great agreement with the calculated ones.