Numerical Simulation Of The Flow Field Of Air Compressor For Vehicle Turbocharger

Nowadays,the exhaust gas turbocharger technology is increasingly being taken seriously and is widely used in various vehicle power system to achieve high engine power,high torque and low emission targets.The centrifugal compressor as a key component of the turbocharger system,its performance is the key of the turbocharger technology.Therefore,the design of a centrifugal compressor with high pressure,high efficiency,low noise and small volume etc.is a priority.Centrifugal compressor is mainly composed of inlet,rotating impeller,diffuser and volute parts.The simple set-up makes the change of the structure on any component a crucial impact on the performance of the compressor.However,with the deepening of research,more and more scholars believe that the effect of coupling actions between various components on the compressor performance cannot be ignored.The numerical simulation of compressor based on this point,which can provide a certain reference for the future research and development of the compressor.In this paper,a type of turbocharger centrifugal compressor was used to the research prototype.First of all,consider effects of diffuser and volute coupling effect on the compressor performance,from expanding pressure outlet relative to the position of the volute perspective,established two structures compressor full model,these two compressor have flow field and acoustic field of full port numerical simulation,and the internal flow characteristics were analyzed.The results showed that the higher the speed,the greater the value of exports static pressure,the larger the pressure ratio;under the same speed conditions,when the flow is small,non-embedded compressor overall performance to higher than the built-in,with the increase of the flow rate,the overall performance of the embedded to higher than the non-embedded;Under the design condition,the compressor performance of non-embedded diffuser and volute combination mode is better than embedded,the whole surface of the maximum sound power is lower than the built-in compressor 4.936 dB.Taking into account the impact on compressor performance rotor portion is large,hence the reference rotor blade design parameters,by changing the outlet angle of the rotor blades for numerical simulation of full flow and analyzed the flow impact characteristics.Results show that a larger blade outlet angle will increase the operating range of compressor,but excessive outlet angle is bad for improve the compression ratio and efficiency,namely it will gradually decrease as the blade of the outlet angle increases;For noise,the machine sound power is manifested with the increase of outlet angle first decreases and then increases,that there is a suitable outlet angle so that the compressor's overall noise is relatively small in design condition.