凸轮转子泵的流场及脉动特性数值分析

随着舰船减振降噪要求的进一步提高,管路噪声逐步成为这一目标的主要障碍,而泵类设备则是管路噪声最主要的噪声源.传统离心泵由其高转速及强烈的动静干涉决定了它在进一步降低自身诱导噪声上的局限性,而新型的凸轮转子泵则具有较大的优势.因此为研究该型泵的主要性能与流场特性,在系统分析凸轮转子泵的工作原理及技术特点的基础上,建立了该泵的二维、三维直翼、三维扭曲翼模型,通过基于动网格的CFD分析计算了凸轮转子泵的流场及脉动特性.计算结果表明:新型凸轮转子泵的流量与转速呈线性关系且呈现出周期性脉动;泵内压力分布稳定,各区域没有明显的压力梯度,在转子间隙及进出口区域存在旋涡及流动分离现象,此处流速较大;转子泵泵内压力脉动随转子叶片数的增大及采用螺旋翼型能够得到有效降低,而随着转速的增大也会迅速增大.

Numerical analysis of flow field and pulsation characteristics in rotary lobe pump

Pipeline noise increasingly becomes the main obstacle to reduce ship vibration and noise level. Pump equipment are the main source of pipeline noise in various ships, however, there is strictly limitation in lowering flow-induced noise level of a traditional centrifugal pump in which there is a high rotational speed and a strong rotor-stator interaction. Fortunately, the rotary lobe pump has a great advantage in reducing flow-induced noise. 2D and 3D straight and twisted lobes model pumps were built based on the working principle of rotary pump, and the flow field and pressure fluctuation characteristics in those pumps were analyzed by using CFD dynamic mesh method. The results show the flow rate has a linear relation with pump rotational speed but exhibits a periodic property. The pressure is distributed uniformly in the pumps and there is no obvious pressure gradient in the flow field. Howe-ver, there are vortex zones and flow separation phenomenon in the gap between two lobes and in the inlet and outlet of the pumps. The pressure fluctuation can be effectively reduced with increasing number of lobes and by using a spiral wing. Unfortunately, the pressure fluctuation still augments rapidly with increasing rotational speed.