离心泵变工况流场分析及数值模拟

Analysis and numeric simulation of off-design flow field in centrifugal pump

针对一离心泵内部流场进行数值计算,计算采用雷诺时均方程和RNGk-ε湍流模型,压力和速度耦合采用SIMPLEC算法.在分析变工况离心泵内部流场的基础上,提出离心泵径向力数值预测的数学模型.分析结果表明,小流量工况时离心泵径向力最大,设计工况时径向力最小;小流量工况时径向力矢量方向在蜗壳第Ⅲ断面和第Ⅴ断面之间,大流量工况时径向力矢量方向在蜗壳第Ⅶ断面和隔舌之间,设计工况时总径向力在蜗壳第Ⅴ断面和第Ⅶ断面之间.对比径向力数值预测值和"Stepanoff"公式值的差异,设计工况时误差在2%之内,非设计工况时误差在5%之内.

By adopting time averaged N-S equations and RNG k-ε mode, the impeller-volute coupling characteristics were simulated with SIMPLEC algorithm. Based on the analysis of off-design flow field, the radial force calculation model was established, and the radial forces were respectively calculated for different flow rate conditions, also. The results revealed that the maximal radial force occurred in the condition of low flow rate, and the minimal radial force occurred in the condition of large flow rate. In the former case, the vector direction of radial force took place in the range from section Ⅲ to section V. In the latter case, the same in the range from section Ⅶ to the tongue. It was found by comparing numerical prediction with ＂Stepanoff＂ results that the error was within 2% under design condition and 5% under off-design conditions.