双向流道立轴潜水泵系统流动特性研究

Flow Characteristics of Two-way Passage Vertical Submersible Pump System

摘要:

为探索将潜水电泵和双向流道泵装置结合在一起的双向流道潜水电泵系统，通过CFX软件对该系统进行全流道数值模拟，获得了系统内的流动特性，并预测了泵装置的水力性能。对进水流道内加设不同导流措施的水流特性进行了分析，结果表明，加设椭圆线导流锥的进水流道出口流速分布均匀度效果最好，能够防止有害旋涡，保证水泵运行的进水条件。应用特别设计的、单边18°的大扩散角出水室，有效地抑制了脱流和水力损失，确保水泵系统整体效率水平。在高精度水力机械试验台进行了模型试验。试验结果表明，泵装置扬程为3.11m，流量为256L/s，泵装置效率达到71.9%，正、反向分别高于可逆式双向潜水泵装置7和13个百分点。说明双向流道配立轴潜水泵装置具有良好的工程应用价值。模型试验结果和性能预测结果在高效区范围内吻合，数值计算得到较好的验证。

Abstract:

The submersible axial-flow pump system has been more widely applied in pumping projects. Usually the existing submersible pumps used for bi-directional pumping stations are the reversible pumps, the forward and reverse pumping of which is less efficient. The flow characteristics of a new bi-directional submersible pump system combined with the submersible pumps and two-way passages together were explored. By CFX software the full-flow numerical simulation of the system was made and the system flow field was obtained. Also the system hydraulic performance was predicted. The flow characteristics of suction passage with different measures were analyzed. The velocity distribution uniformity at outlet of suction passage showed the elliptical-type flow guide cone of the passage worked the best to prevent harmful vortex, which guaranteed the flow conditions of pump operation. Using specially designed discharge-chamber with unilateral angle of 18°, the flow separation was effectively inhibited, the hydraulic losses were reduced which ensured the overall efficiency of pump systems at high level. A model test was conducted in the high-precision test-bed of hydraulic machinery. The test results showed that under the pump head of 3.11m, flow rate of 256L/s, the pump system efficiency reached 71.9%, which was above the forward or backward pumping efficiency of reversible pump system by 7 and 13 percentage points, respectively. It was evident that the vertical submerged pump system with two-way passage was suitable for bi-directional pumping station. Experimental results and predicted model performance results were consistent in high efficiency area, and the numerical calculations were well verified.