极大流量工况下离心泵内部流场数值分析

针对离心泵极大流量工况下内部流动特性的问题,应用流体动力学软件Fluent,采用RNGκ-ε湍流模型与SIMPLEC算法,对某一高比转速离心泵内部流场进行了数值模拟,并与实验结果进行了比较。对比分析了4种不同流量工况下离心泵内部流体速度和压力分布以及离心泵的外特性。研究结果表明,在设计流量工况下,离心泵内部压力分布均匀,速度迹线平滑;较大流量工况下,蜗壳压力不断减小,速度分布不均匀;极大流量(1.7Qopt)工况下,蜗壳出口处出现局部负压现象,速度流线产生的漩涡增大,在扩散管局部位置流体受到冲击,容易出现回流现象。针对离心泵在不同工况下以及达到极大流量工况下内部流动随流量变化规律的研究,可为高比转速离心泵多工况优化设计、延长使用寿命提供参考。

Numerical analysis for inner flow field in a centrifugal pump under maximum operating conditions

Aiming at studying the inner flow under maximum operating conditions, a centrifugal pump was simulated by adopting RNGK-e turbulence model Hydraulic performance was predicted and the calculation results were compared with the experiment results. Fluid velocity, pressure distribution and external characteristics were analyzed under 4 operating conditions. The results indicate that pressure and velocity distribute uniformly under the optimum flow rates condition. At large flow rates point, the volute pressure decreases and the velocity distribution is not uniform. At the maximum flow rates point（ 1.7 Qopt ）,negative pressure appears at the inlet of the volute. Vortex of the velocity flow lines become larger and occurs reflux in the local position of diffusion tube. The study reveal pump inner flow rules, which provide reference to the high specific speed centrifugal pump optimal design and extending service life under variable flow rates operating conditions.