轴流泵前置导轮内部流场的大涡模拟

前置导轮自身具有优良的进口性能,能够改善主叶轮的进口条件,使用盒式滤波器将连续方程和动量方程经空间滤波得到大涡模型.采用CFD软件,对设计工况下带有前置导轮轴流泵进行三维不可压缩湍流数值模拟.分析了前置导轮内部流场的压力、速度和流线分布情况.结果表明,导轮叶片静压由进口到出口不断增大,提高了轴流泵抗汽蚀性能;叶片进口背面有一个低压区,此处易发生汽蚀;叶片表面的压力分布不仅沿叶片导程的方向逐渐增加,径向上也有增加,且没有发生较大的冲击和二次流现象;流线沿导轮型线良好地缠绕,没有出现回流、漩涡等现象.结果对轴流泵的设计、改进和优化提供有益的参考.

Large eddy simulation of interior flow field in front guide impeller of axial flow pump

The front guide has excellent performance of inlet, and can improve the condition of inlet of the main impeller. In this paper based on large-eddy model obtained from spatial filtering of continuity equation and momentum equation and by CFD software, the three-dimensional incompressible turbulent flow of front guide impeller of axial flow pump was simulated under the design condition. The velocity, pressure and streamline distribution of the internal flow field of front guide impeller are analysed. The results show that the increase of the static pressure of guide blade from inlet to outlet enhances anti-cavitation performance ; there exists an area prone to cavitation in inlet of back blade ; blade surface pressure dis- tribution increases along the blade lead and radial direction,and no great impact and secondary flow phenomena occur. Streamline along the guide impeller winds well,and the phenomena of vortex and circumfluence don＇t appear. A useful reference of axial flow pump design, improvement and optimization was obtained.