The Study Of Salt-Out Liquid-Solid Two-Phase Flow In Pipe And Centrifugal Pump Chamber

Research works in this paper are financed by the item of National Science Fund of China "study on the liquid-solid two-phase flow with salt-out in turbine machines". (No.50476068)The liquid-solid two phase flow with salt-out phenomenon is widely exist in nature and modern industry. In order to better understand the salt out mechanism and provide some reference to the optimal design of transportation salt solution equipment, the fundamental and experimental research as well as the numerical simulation of the salt out two phase flow was carried out in pumping chamber and pipe based on the former researches. The main works and conclusions are showed as following.1. Present research states of salt-out liquid-solid two-phase flow in pipe and pumping chamber were introduced simply. The experimental salt-out two phase flow system in pipe was designed independently and the comprehensive measurement research to pipe about the solution of velocity and granule diameter distribution under different work conditions were surveyed by the Phase Doppler Particle Analyzer (PDPA) system. Conclusions were proposed such as "under the state of laminar flow in pipes, the probability of initial nucleation in salt out solution is higher than in surface nucleation, which was the magistral mechanism of nucleation ".2. According to actual situation, the non-homogeneous phase nucleation mechanism was considered to be the magistral mechanism in salt out crystallization, simultaneously it was thought that the salt out crystal growth must satisfy thermodynamics condition and the structure condition.3. The two-fluid model was considered to be the reasonable model to expression the salt-out flow. The particle cloud model was analyzed about its characteristic and advantage, which was used to establish the liquid-solid two phase flow control volume of the pipe and relatively integrated established salt-out two phase laminar flow governing equations including mass equations, momentum equations and energy equations.4. Pro/E was applied to sculpt the model pumping chamber. The unstructured grids were generated in the area of flow passage in the pump. In order to improve the grid quality and quicken the solution velocity, local encryption techniques were adopted. 5. Euler multiphase flow model and modified k-εturbulent model were adopted to coupling calculate internal liquid-solid two-phase flow field at different work conditions of pump. Axial cross-sections and regions were plotted to locate every measure point and display the results for comparing with the measurement results. Conclusions were obtained such as "the secondary flow has existed in the various radial section of pumping chamber".6. Measuring means on two-phase flow with Particle Image Velocimetery (PIV) were introduced. The salt-out two phase flow of different work conditions in pumping chamber were measured by PIV, while the experimental and calculation results were compared and analyzed.