叶片V型切割对双吸离心泵性能影响研究

The Effect of Blade V-Shaped Trim on the Performance of Double-Suction Centrifugal Pumps

基于传统的切割定律换算发现在小流量工况下,叶轮切割值不能按照传统的切割定律来选取。为了研究不同叶片切割值对低比速双吸离心泵性能的影响,以MS59-160型双吸式离心泵为研究对象,对其叶片进行V型切割,采用CFD数值模拟对切割后的双吸离心泵流体动力性能进行预测。研究结果表明:小流量工况下,效率预测值比试验值略低,而大流量工况时二者吻合较好;随着切割角度的增加,叶轮出口处及蜗壳内的高压区呈梯度扩散且压差逐渐减少;当角度15°时,叶轮出口和蜗壳内部的压力梯度分布相较于切割前分布变得均匀;叶轮效率降低的主要原因是叶轮内部出现漩涡,随着切割角度的增加,漩涡面积剧增且在叶轮出口靠近前盖板处。

After the conversion based on the traditional trimming law found the value of cutting cannot be selected in accordance with the trimming law under small flow rate conditions.For doing research on the influence of blades trim on performance of low specific speed double suction centrifugal pumps,as the research object the MS59-160 double suction centrifugal pump＇s blades is v-shaped cutting,and then based on the CFD numerical simulation the hydrodynamic performance of double suction pump after trimming is predicted.The research results show that the prediction efficiency is slightly lower than the test results at the small flow rate.On the contrary,which can better coincide during the large flow rate.With the increase in cutting angle,the outlet of the impeller and volute produced high gradient diffusion and the differential pressure gradually decreased.When the angle is 15°,the pressure gradient distribution becomes uniform compared with before cutting in the outlet of impeller and internal of volute.From the distribution of streamline,the main reason of the low efficiency of impellers comes to the internal spiral,with the increase in cutting angle,the vortex area is surge in the outlet of impeller near the shroud.