固定叶轮水动力性能数值分析

Numerical analysis of hydrodynamic performance of fixed impeller

为研究螺旋桨后固定叶轮的节能效果,采用计算流体力学(CFD)方法对螺旋桨与固定叶轮进行仿真模拟。计算域划分为螺旋桨小域、叶轮小域、外部大域等3个区域,三者均采用结构网格。计算域整体为圆柱形区域,与螺旋桨同轴,靠近螺旋桨与叶轮区域网格加密,来流采用均匀流,分别改变进速系数、螺旋桨与叶轮距离以及叶轮叶数等参数,依计算结果选取最优解并按照加法原则划分并在计算过程中增减工况。分析认为:在距离为0.7D、进速系数1.0、叶轮叶数5叶时,节能效果最佳;同等情况下,效率较不加叶轮提高9.46%。

In order to study the energy saving effect of a fixed impeller after the propeller, this paper carries out the numerical simulation of the fixed impeller and the propeller by computational fluid dynamics （CFD） method. The calculation domain is divided into three regions with the structured grid： a small propeller domain, a small impeller domain and a large external domain. The entire computational domain is a cylindrical region coaxial with a propeller in it. The mesh close to the propeller and the impeller is refined. The inflow is taken as uniform flow. The optimal solution is selected according to the results calculated by different advance coefficient, distance between the propeller and impeller and number of impellers, respectively. The results are divided and calculated under increased or decreased operation conditions based on the additional principle. It is indicated that the best energy saving effect is achieved with a distance of 0.7D, advance coefficient of 1.0, and five impeller blades. The efficiency increases by 9.46% compared with that under same conditions but without impeller.