长短叶片结构对凝水泵出口压力脉动特性的影响

为探究不同长短叶片结构下凝水泵出口管道内的压力脉动特征,深化对泵系统内非定常流动机理的理解,在定常数值模拟的基础上,采用非定常数值模拟方法对泵及出口管内的流动进行模拟与分析,研究不同工况下泵出口管内的压力脉动与监测点位置和流量之间的关系,对各叶片结构对应的压力脉动的频域特征和能量特性进行对比研究.研究结果表明:5长5短叶片结构对应的凝水泵外特性优于3长3短叶片结构的;各监测点在4个流量工况下的主频保持为叶频f_BPF及其倍频.3长3短叶片结构较5长5短叶片结构泵出口压力脉动更明显,变化更复杂;泵出口法兰监测点处的压力脉动强度较高,沿流动方向,自监测点P₁至P₃,压力脉动逐渐衰减;对于3长3短叶片结构,在1.4Q_d流量工况下,泵出口管内呈现多频率激发的压力脉动特征,非稳态流动激励加剧.

Effect of long and short blades on outlet pressure fluctuation characteristics of condensate pump

In order to explore the pressure fluctuation characteristics in the outlet pipe of the condensate pump under the conditions of different long and short bladed structure, and deepen the understanding of the unsteady flow mechanism in the pump system. On the basis of the steady numerical si-mulation, the unsteady numerical simulation method was used to analyze the flow inside of the pump and the outlet pipe. The flow of the pump was simulated and analyzed, and the relationship between the pressure fluctuation in the pump outlet pipe and the position of the monitoring point and the flow rate under different working conditions was studied. The frequency domain characteristics and energy characteristics of the pressure pulsation corresponding to each bladed scheme were compared. The research results show that the external characteristics of the condensate pump with 5 long and 5 short blades scheme are better than the 3 long and 3 short blades scheme. The main frequency of each monitoring point is maintained at the blade frequency f_BPF and its multiplier under the four flow conditions. The pump outlet pressure pulsation of the pump with 3 long and 3 short blades is more obvious and the change is more complicated when compared with that the 5 long and 5 short bladed scheme. The pressure pulsation intensity at the monitoring point of the pump outlet flange is higher, along the flow direction, the pressure pulsation gradually attenuates from the monitoring point P₁ to P₃. For the 3 long and 3 short blades scheme, under the condition of 1.4Q_d flow-rate, the pressure pulsation characteristic of multi-frequency excitation in the pump outlet pipe is presented, and the unsteady flow excitation is intensified.