圆形喷灌机系统两井泵汇流装置水力性能研究

Hydraulic Characteristics at the Confluence of Two Submersible Pumps in Center-pivot Irrigation

【目的】为了满足入机流量需求,圆形喷灌机在实际应用中常用多台井泵并联供水,在喷灌机入机处安置井泵汇流装置,以调节流量和稳定水压。【方法】通过设计两井泵汇流装置,开展了汇流装置水力性能试验及数值模拟,研究了雷诺数和两进口汇流比(较小流量与较大流量之比值)对装置水力性能的影响。【结果】汇流装置的总水力损失模拟值与试验值较吻合,相对误差范围为0.5%～3.3%,且随雷诺数和汇流比均呈二次函数关系,当汇流比为0.8左右时,装置的总水力损失最小;两进口对应的局部阻力系数均不随雷诺数产生变化,但随汇流比变化趋势相反,当汇流比为0.2～1.0之间时,较大流量进口的局部阻力系数为1.16～1.31,较小流量进口的局部阻力系数为1.31～4.22。【结论】两井泵汇流装置结构及水力性能可用于圆形喷灌机灌溉工程设计和运行管理。

【Objective】Double submersible pumps are often used in parallel in center-pivot irrigation to meet the requirement for flow rate, with a confluence device installed to regulate the inlet flow rate and stabilize the work-ing pressure.The purpose of this paper is to analyze the hydraulic characteristics at the confluence.【Method】The study was based on numerical simulation, in which we examined the impact of Reynolds number and the conflu-ence ratio (ratio of the maximum flow rate to the minimum flow rate at the inlet) on the hydraulic characteristics at the confluence.【Result】It was found that the relative error of the simulated hydraulic loss at the confluence was in the range of 0.5% to 3.3%, compared to the experimental measurement.The hydraulic loss was quadrati-cally related to the Reynolds number and the confluence ratio, with minimum hydraulic loss achieved when the confluence ratio was 0.8.In addition, the local resistance coefficient at the two inlets was independent of the Reynolds number, but changed with the confluence ratio.When the confluence ratio varied between 0.2 and 1.0, the local resistance coefficient varied between 1.16 and 1.31 at the large flow inlet, and between 1.31 and 4.22 at the small flow inlet.【Conclusion】The structure and hydraulic performance of the confluence can be used in engi-neering design and operational management of the center-pivot irrigation system.