熔盐泵盐析两相流冷态模型试验和数值研究

Cold model experiments and numerical study on crystallization two-phase flow in molten salt pump

为了揭示熔盐泵内盐析两相流动的规律,采用白金汉定理,建立了熔盐泵输送固液两相流的相似准则,根据所设计的熔盐泵模型试验方案,对熔盐泵内部流动进行了数值模拟,采用高速摄像技术捕捉了泵内的盐析两相流动,阐述了试验结果与模拟结果之间的差别。研究了颗粒直径和密度对熔盐泵外特性和内部流动的影响。结果表明:数值模拟结果和试验结果之间的误差小于10%。叶轮流道出口处颗粒的绝对速度从叶片的压力面到吸力面逐渐减小。分析得到了叶轮内固相和液相的速度三角形之间的关系,当颗粒的密度大于液相的密度时,颗粒绝对速度沿圆周方向的分量小于液相。进一步分析得到了叶轮出口处密度分别为2 000、2 250、2500、2750、3000kg/m^3的颗粒的运动速度三角形之间的关系,颗粒密度越大,叶轮出口绝对速度沿圆周方向的分量越小,泵的扬程越小。

In order to reveal the regularity of the crystallization two-phase flow in the molten salt pump,Buckingham theorem was adopted to establish the similarity criterion for the solid-liquid two-phase flow in molten salt pump.According to the designed molten salt pump model test schemes,the internal flow was numerically simulated.At the same time,the high speed photography technology was employed to capture the flow.The differences between experimental and numerical simulation results were elaborated.The effects of particle diameter and density on external performance and internal flow of molten salt pump were researched.The obtained results were shown as follows：the error between the numerical simulation results and the test results was less than 10%.The absolute velocity of particlesat the impeller outlet decreased from the blade pressure surface to the suction surface.The relationship of the velocity triangles between the solid and liquid phases in the impeller was obtained.When the particle density was greater than the liquid density,the circumferential component of the particle absolute velocity was less than that of liquid phase.Furthermore,the relationship of the velocity triangles at the impeller outlet was obtained for particles with the density of 2 000,2 250,2 500,2 750,3 000 kg/m^3.The larger particle density meant the smaller circumferential component of the absolute velocity and the lower pump head.