不同流量下自吸泵能量损失与流动特性研究

Energy Loss and Flow Characteristics of Self-priming Pump under Different Flow Rates

摘要:

本文基于熵产理论与Q准则涡识别方法，对自吸泵在不同流量工况下内部流动特性及能量损失机理展开了系统性研究。研究结果表明：自吸泵内部能量损失以湍流熵产为主，平均占比达63.8%;吸入室与气液分离室湍流熵产损失对流量变化较为敏感，随流量增大，二者最大相对增长率分别达到72.2%和44.8%;叶轮与蜗壳断面Ⅳ~Ⅷ区域湍流熵产主要由湍动能主导，而在隔舌附近、断面Ⅱ、Ⅲ之间、回流孔以及气液分离室出口等区域，湍流熵产则由湍动能和涡动频率共同主导;分离涡是气液分离室内能量损失的主要来源，涡强度占比随流量增大从7.2%上升至34.1%，尾迹涡与通道涡共同主导了蜗壳区域的能量损失;随流量增大，吸入室和气液分离室壁面熵产最大相对增长率分别为60.4%和28.7%，蜗壳和叶轮最大相对增长率为-7.4%和-7%。

Abstract:

Based on the entropy production theory and the Q-criterion vortex identification method, the internal flow characteristics and energy loss mechanism of a self-priming pump under different flow rate conditions were systematically investigated. The results showed that the energy loss inside the self-priming pump was dominated by turbulent entropy production, which accounted for an average of 63.8% of the total loss. The turbulent entropy production losses in the suction chamber and the gas-liquid separation chamber were highly sensitive to variations in flow rate;as the flow rate increased, the maximum relative growth rates of these two losses reached 72.2% and 44.8%, respectively. In the impeller and the volute regions from the fourth to the eighth cross-sections, the turbulent entropy production was primarily governed by turbulent kinetic energy. In contrast, in the regions near the tongue, between the second and the third cross-sections, around the return hole, and at the outlet of the gas-liquid separation chamber, the turbulent entropy production was jointly governed by turbulent kinetic energy and vorticity frequency. The separation vortex was the main source of energy loss in the gas-liquid separation chamber, with its vortex intensity proportion increased from 7.2% to 34.1% as the flow rate increased. The wake vortex and the channel vortex jointly dominated the energy loss in the volute region. As the flow rate increased, the maximum relative growth rates of wall entropy production in the suction chamber and the gas-liquid separation chamber were 60.4% and 28.7%, respectively, while those in the volute and the impeller were -7.4% and -7%, respectively.