Design And Investigation On The Ejector With Complex Passage For Pumping Air Containing Sand Particle

In military and other special occasions, helicopter sometimes operates in dusty environment.Asa result, engine of a helicopter faces a harsher environment than an ordinary fixed-wing aircraft does,engines intake significant amount of dust and sand dirt which will not only erode and wearcompressor blades but also block the cooling passage. An important way of the inlet protection ofhelicopter is using the particle separator to separate the solid particle.Take the inlet protection of helicopter as the background, usage of the engine’s high pressurebleeding air or the exhaust to eject and separate the dusty air was studied. Based on the theoreticalknowledge and relevant experience at home and abroad, structure of ejector with complex passage forpumping dusty air in particle separator was designed.A multi-nozzle ejector was designed to improve the performance of the ejector, the axialdirection as the eject fluid while the circumferential direction as the working fluid depended on theapplication requirements. Numerical simulation was carried on the designed model, variables ofaerodynamic parameters and structural parameters were calculated to study the effect on theperformance of ejector, results show that: Aerodynamic and structure parameters are of a greatimpact. The entrainment ratio increases as the temperature ratio rises while decreases when thepressure ratio or the inlet resistances of eject fluid rise. The structure of nozzle is of a great impactalso. The entrainment ratio of multi-nozzle ejector is higher than single nozzle ejector but not themore the better. The area ratio, the throat-nozzle distance, the length-diameter ratio of mixing pipeand the nozzle-distribute exists an optimum value for a best performance. The entrainment ratio goesdown as the inlet angle of the suction chamber and the diffuser angle increases. Ejector performanceis the best when the mixing pipe is cylindrical while the worst for the ellipse. For square and therunway-shaped structure of the mixing pipe, entrainment ratio shows crossover value, but on theoverall trend, ejector performance with square mixing tube structure was better than therunway-shaped structure. Transition section was designed and studied, shows that ejector performanceincrease as the bending angle decrease and the radius of curvature increases.Based on the calculation results, the factors influencing the ejector and impact of the law on theaerodynamic parameters and structural parameters were explored, and then the best performancestructure size that optimize the performance of the ejector were determined and the research of thegas-solid phase flow in it was carried out.