Profile Analysis And Optimization On Helicopter Inertial Particle Separator

Helicopter is often near the ground flight, including low-altitude hover, takeoff,landing and so on. Ground dust and other solid particles which are raised under theinfluence of suspended wing will be sucked into the engine along with the gasrefrigerant inevitably. The range of diameter distribution of these particles is wide,from micron magnitude to millimeter magnitude, even arrives decimeter magnitude.Large-scale particles collide with the compressor blades and can damage them,while the metal debris peeling off from the blades can get into the downstreamcomponents, which are doped in the gas refrigerant. Because of high hardness andsharp corners of the metal debris, they can cause more damage to the downstreamcomponents. Small-scale particles which may adhere to the compressor blades candamage their dynamic balance,and even can change the actual type line of theblades, which will reduce efficiency of compressor.In addition, these particles mayjam injection mouth and film cooling hole, which will affects the performance andsafe operation of engine unit and shorten its service life.To meet the work requirements of helicopter and to reduce the damage which iscaused by the particles doped in the gas refrigerant, it's necessary to install particleseparators in engine entrance. Considering the limits of helicopter componentstructure and the requirements of its work performance, an inertial particle separatorwas usually selected. In order to analyze the flow field and performance parametersof inertial particle separator and optimize its flow structure, this paper developed a set of parameterized automatic modeling software for separator firstly. Based on thesoftware, we finished the numerical computation for original separator model, andanalyzed its result of gas phase. We got the performance parameters of the separator,and analyzed the motion law of different diameter's particles within separator. Thensix important parameters were selected, which controlled bending degree of separatorinlet port, section area of throat, position of the biggest radius of outside wall, lengthof tongue department and so on. Then we did detailed numerical analysis andcomparison for the performance of about 150 separators. Based on the results, thenonlinear relationship of parameters of separator flow structure line and particleseparation efficiency and total pressure loss of separator was established by the neuralnetwork. we got the approximate optimal solution of separation efficiency and totalpressure loss of separator by the genetic algorithm. Compared with the original model,the separation efficiency of large-scale particles was increased for the improvedmodel, from less than 20% to about 90%,while the total pressure loss was increasedslightly. The efficient work scope of separator was also greatly expended afteroptimization, the separation efficiency of large-scale particles is all high for optimizedmodel when inlet velocity is in the range of 30m/s to 70m/s and clear flow ratio wasin the range of 0.12 to 0.20. This study has laid a good theoretical basis for optimaldesign of inertial particle separator.