熔盐泵空间导叶与叶轮的径向安装间隙对泵性能影响研究

为了探究空间导叶和叶轮之间的径向安装间隙对泵性能影响规律，选择某VS1型太阳能高温熔盐泵首级部分作为研究对象，在其他几何参数不变的前提下，以原导叶和叶轮径向间隙值为基础，通过沿径向逐次改变导叶进口和叶轮之间的相对位置，共设计了6组不同间隙下的导叶-叶轮组合方案，基于CFD方法对6种间隙方案(1.5～6.5 mm),进行了全流场数值模拟，并试验验证了数值算法的可靠性。研究表明：导叶与叶轮径向安装间隙对泵扬程和效率在不同工况下的影响具有显著差异性，存在较优间隙使泵性能整体最佳，间隙过大、过小时都会致使其性能劣化；与原间隙2.5 mm时相比，合适的间隙可使叶轮出口和腔体间隙处的主频压力脉动幅值分别降低20.6%和36.4%,泵内介质流动稳定性提升；导叶内流道压力梯度和腔体涡核心分布随间隙改变呈不同变化态势，间隙为4.5 mm时，导叶内流道压力梯度变化更为均匀有序，腔体内涡的范围和强度较其它方案削弱明显，泵内流态最优。

Research on the Influence of Radial Installation Clearance between Spatial Guide Vane and Impeller of Molten Salt Pump on the Performance of Pump

In order to explore the influence of the radial installation clearance between spatial guide vane and impeller on the pump performance, the first stage part of VS1 solar high temperature molten salt pump was selected as the research object. On the premise of other geometrical parameters unchanged, based on radial installation clearance of original guide vane and impeller, through successively changing the relative location between the radial guide vane inlet and impeller, a total of 6 combination schemes of guide vane and impeller with different clearance were designed for comparative analysis. Full flow field numerical simulation ranging from 1.5 to 6.5 mm in six clearance schemes was carried out using CFD method, and the reliability of numerical algorithms was validated through experimental testing. The results show that the influence of the radial installation clearance between guide vane and impeller on pump head and efficiency is significantly different under different working conditions. A better clearance leads to the best overall pump performance, while too large or too small clearance will lead to deterioration of pump performance; compared to the original clearance of 2.5 mm, an appropriate clearance can reduce the amplitudes of the main frequency pressure pulsation at the impeller outlet and cavity clearance position by 20.6% and 36.4%, which increases the stability of the fluid flow within the pump; the pressure gradient in the guide vane internal passage and the distribution of the vortex core in the cavity exhibit different change trends with the change of clearance. When the clearance is 4.5 mm, the pressure gradient in the guide vane internal passage changes more uniformly and orderly, and the range and intensity of the vortices in the cavity are significantly reduced compared to other schemes, leading to the optimal flow state in the pump.