Research On The Effect Of Intake Pipe On The Efficiency Of Two-stage Compressor

In recent years,the emission requirements of engines have become more stringent,so that turbocharging technology has received more attention.Single-stage centrifugal compressor turbochargers have been widely used in recent years,which can better improve engine power and economy.Not only that,the use of turbocharging can also reduce emissions to a certain extent.However,single-stage turbocharging technology currently has problems such as poor characteristics at low operating conditions,such as poor low-speed response and insufficient low-speed torque.Not only that,when single-stage turbocharging is used in engine plateau conditions,power loss is severe In order to solve the problem caused by single-stage supercharging,researchers have begun to increase the engine supercharging pressure ratio,and this method will make the above problem more serious.The two-stage turbocharger system has received more and more attention by using two turbochargers together.The two-stage turbocharging system can efficiently convert the exhaust gas energy.The efficiency of the compressor directly affects the efficiency of the two-stage turbocharging system,which affects the improvement of engine performance.In recent years,there have been few studies on the two-stage supercharging system,and they are basically based on the matching study of the overall performance.However,due to the installation space of the two-stage supercharging system,it is necessary to use curved pipe air intake to meet the overall layout requirements.The airflow loss will be caused when the pipe is inhaled,which will have different effects on the compressor efficiency.Therefore,it is very necessary to study the influence of bent pipe intake on the compressor efficiency.This article takes a secondary turbocharger under development as the research object,and conducts performance experiments on the low-pressure compressor and the high-pressure compressor through the compressor performance test bench,and the parameter data required for later calculation and analysis are measured and obtained the high-pressure compressor and the low-pressure compressor MAP are drawn,and the flow-pressure ratio and flow-efficiency curves of the high-pressure compressor and the low-pressure compressor are drawn.Using NUMECA software,a numerical simulation method was used to study the effect of the bent pipe inlet on the efficiency and internal flow field of the high-pressure compressor.According to the requirements,nine different types of bent pipes were designed to better compare different types of bent pipes The effect of intake air on compressor efficiency.Through numerical calculation and analysis,the results show that the intake of curved pipes deteriorates the compressor efficiency to varying degrees.In terms of the three common types of elbows designed,the efficiency of the compressor has decreased compared with straight pipes.Among them,the efficiency of the 90° elbow intake compressor has the most obvious decline,with a maximum decline of 7%;The efficiency of the compressor during the intake of the flow plate bend is higher than that of the ordinary 90° bend intake,which has a positive impact on the efficiency of the compressor.Different forms of intake with a baffle bend have different effects on efficiency Compared with 90°elbow intake air compressor,the efficiency of the compressor with a baffle can be increased by up to 3%;the impact of the pinch flat elbow air intake on the compressor efficiency is the most uncertain.The efficiency of the compressor can be increased,and different pinch flat bends will cause the efficiency of the bent air intake compressor to decrease to varying degrees.The efficiency of all compressors with curved intake is lower than that with straight intake.Not only that,the numerical calculation also studies the different degrees of influence of different forms of curved intake air on the impeller channel and the internal flow field of the pipe.