Design On Two-Stage Turbocharger System Of The Engine And The Performance Simulation Analysis

As the altitude increases, atmospheric pressure decreases, air density decreases, which will have a huge impact on the power and economy of the aeroengine. At present, the supercharger technology has become the most effective means of the high-altitude environment engine to restore its power. As the UAV altitude increasing needs, the single stage turbocharging system can not meet it, so it is essential to do some deep research on the two-stage turbocharging system.Based on the research of the existing two-stage turbocharging system on the engine and its application,this paper proposed three kinds of two-stage turbocharging system according to the characteristics and requirements of the specific engine, that is the regulated two-stage turbocharging system, the regulated two-stage turbocharging system with bypass valve and the sequential two-stage turbocharging system, then did some comparison on them. Using the software simulation method, firstly set up the matching simulation model of the aviation gasoline engine with original single-stage turbocharging system. On the model, the performance of the original engine and its matching characteristics with the single-stage turbocharging system was calculated; then build the matching simulation model of engine with the two-stage turbocharging system, and the engine performance, supercharger going, release valve and bypass valve discharge gas discipline, etc under different programs had been calculated.The results show that on the basis of a single-stage turbocharging system, using two-stage turbocharing system it could provide a bigger pressure ratio, but the engine inlet temperature rised sharply. So two coolers were arranged after the compressors in the high and the low grade to achieve a better cooling effect, so as to effectively improve the engine altitude during take-off condition and the maximum endurance condition. As to the adjustable two-stage turbocharging system, the turbine of first stage firstly reached its maximum flow rate, which limited the pressure ratio improving.As to the adjustable two-stage turbocharging system with bypass valve, it can make a further bigger pressure ratio so as to a further higher altitude of the engine. Using two-stage sequential turbocharging system, when the engine runs at a lower altitude, it can greatly improve compressor efficiency and with a more simplified exhaust system, the engine fuel consumption can get even lower, economical efficiency can be improved.