The Flow Field Test Of Helicopter Inertial Particle Separator And Numerical Simulation Research

In order to protect the helicopter engine from being damaged by the foreign materials and to improve it's operation reliability,the inertial particle separator has become the standard component for the helicopter.The inertial particle separator has been widely used in helicopter inlet gas protection device due to the small total pressure loss,high particle separation efficiency and easy to maintenance.Domestic and foreign researches and tests mostly based on the numerical simulation and overall performance tests.Due to the lack of measurement data,it is hard to verify the internal flow structure by the numerical simulation results.In order to improve the overall performance of the inertia particle separator,it is necessary get the internal flow information by experiments.Whereas,there are only the testing data for the rectangular section channel existed in recent years by PIV test.Referring to a product prototype,the transparent inertial particle separator models were designed,and the test rig was built.Two fans were used to control the mass flow rates in the scavenge flow passage and core flow passage.The PIV test technology was used to get the flow information in the rectangular channel model and annular channel model,in addition,the numerical simulation and the high-speed photography technology were used to analysis the gas-solid flow field.Validated by the testing data,the numerical simulation was adopted to optimize the geometric structure of the annular model by the orthogonal test method.According to the experiment results,It was found that there existed an obvious separated flow at the entrance of scavenge flow passage.The backflow vortex behaved differently from the parameter scavenge core ratio(SCR,14% to 20%).The solid wall had great influence on the scale of the separated flow,the more close to the wall,the bigger backflow vortex was.When SCR increases,the scale of backflow vortex became smaller and smaller.With the increase of inlet flow rate,there was little change of backflow vortex scale.It shows that internal flow field and backflow vortex scale was mainly decided by SCR.The gas-solid flow field was tested by PIV and high speed photography measurement technology.It was found that the separation efficiency of the fine sand particles changed with the variation of the vortex.The vortex moves with obvious fluctuation,and separation efficiency is influenced by the backflow vortex size,the larger the size of the vortex,the lower of the separate efficiency of the fine sand particles is.As for the larger particles,they move in linear trajectories,and collide to the wall non-elastically.The movement of the large particles was decided by its inertia force and the shape of the separator.So the separation efficiency is higher than that of the fine particles.The comparison between PIV flow field experimental data and high speed photography particle trajectory test results and CFD calculation results showed that the meshing and k-? turbulence model can meet the demand for the computational accuracy.The annular separator has a smaller total pressure distortion and total pressure loss coefficient with higher separation efficiency,compared with rectangular separator.The model was optimized by the orthogonal test method.By the optimization model,the separation efficiency for the different particle sizes have overall improvement.The total pressure loss of optimized model in the largest working condition is less than 3%.It can be applied to the product.The research of this paper provides a reliable method for the performance analysis of the inertial particle separator,and provides reliable data support for its performance optimization.