进口斜槽对轴流推进泵快速启动瞬态特性影响

Influence of inlet inclined grooves on transient characteristics of axial-flow propulsion pumps during rapid start-up

摘要:

为改善轴流推进泵在快速启动条件下的瞬态性能,解决复杂运行环境下马鞍区扬程下降的问题,提出一种进口斜槽流动控制方法,旨在通过优化入流条件提升泵的稳态及瞬态性能。首先,对轴流推进泵的性能进行数值模拟计算,并通过试验验证数值计算的准确性。其次,设计斜槽尺寸,通过数值计算探究了进口斜槽对轴流推进泵快速启动过程瞬态性能的影响。最后,通过内部流场分析,对斜槽改善推进泵瞬态性能的机理进行探究。结果表明,斜槽有效改善了稳态马鞍区性能,扬程最高提升56.5%。根据扬程的演化,快速启动过程可划分为一次发展区、马鞍区、二次发展区和稳定运行区4个阶段。斜槽改善了启动马鞍区扬程下降的现象,最高提升27.15%。斜槽上下游的局部低压区诱导了斜槽内部的逆向流动,与主流混合,减弱了主流的周向角动量。良好的入流条件改善了泵内的流动分离,抑制了叶顶阻塞涡,减弱了动静干涉区域的压力脉动幅值,提升了快速启动过程的稳定性。

Abstract:

To improve the transient performance of an axial-flow propulsion pump under rapid start-up conditions and address the drop of head in the saddle region under complex operating environments, this paper proposed a control method for imported inclined groove flow, aiming to enhance the steady-state and transient performance of the pump by optimizing the inflow conditions. Firstly, numerical simulation calculation was conducted on the performance of the axial-flow propulsion pump, and the accuracy of the numerical calculation was verified through experiments. Secondly, the sizes of the inclined groove were designed, and numerical calculations were conducted to investigate the influence of the imported inclined groove on the transient performance of the axial-flow propulsion pump during rapid start-up. Finally, internal flow field analysis was performed to investigate the mechanism of inclined grooves for improving the transient performance of the propulsion pump. The results demonstrate that the inclined groove effectively improves steady-state performance in the saddle zone, achieving a maximum head increase of 56.5%. The rapid start-up process is categorized into four stages based on head evolution: primary development region, saddle region, secondary development region, and stable operation region. The inclined groove improves the drop of head during start-up, with a maximum increase of 27.15%. Localized low-pressure zones in the upstream and downstream of the inclined groove induce reverse flow inside the inclined groove, which is mixed with the main flow to reduce circumferential angular momentum. The optimized inflow conditions improve flow separation, suppress the tip blockage vortex, and reduce pressure fluctuation amplitudes in the rotor-stator interaction zone, thereby enhancing the stability during rapid start-up.