Numerical Simulation Of The Flow Field And Aerodynamic Noise And Experimental Study For A High Pressure Ratio Marine Turbocharger Compressor

With the widely use of turbocharger in internal combustion engine, engine performance, fuel economy and emission characteristics had been further improved, and the noise and vibration brought by turbocharger had been drawing more and more attention, so study and optimization of the turbocharger compressor aerodynamic performance had been significant to performance improvement and noise control. Research object in this paper was a marine turbocharger compressor. On the basis of sorting and summarizing domestic and foreign research on flow field and acoustic field of the turbocharger, and through numerical simulation, three-dimensional, viscous, compressible flow field numerical analysis and the simulation prediction of aerodynamic noise had been carried out, noise characteristics and mechanism had been further analyzed with experiment test. Finally structural optimization was proposed to improve the compressor performance.A solid model of compressor was firstly built in this paper, and by dint of ANSYS FLUENT software platform, through numerical simulation of three dimensional, steady, viscous, compressible, internal flow characteristics and its change rule of compressor under different working conditions were analyzed, distribution regularity and genesis of state parameters, such as gas pressure, Mach number, etc, were specifically analyzed and researched in compressor impeller, diffuser and volute.Broadband noise method and acoustic analogy method had been used to analyze the compressor noise distribution laws and its mechanism of sound field. Based on the steady flow field analysis, broadband noise method was used to analyze the distribution features of broadband noise sources under different working conditions. Based on the numerical simulation of unsteady flow field, the acoustic analogy method was used to analyze the spectrum characteristics and formation mechanism of compressor discrete noise spectrum observation point in different position under different working conditions. Field test of turbocharger radiated noise was accomplished to analyze more about spectrum characteristics of the radiated noise.On the basis of numerical simulation on flow field and acoustic field and experimental measurement of the radiated noise, improved design of compressor was proposed mainly by adding SRCT(self recirculation casing treatment) to the original structure, influence of SRCT on the compressor internal flow was also studied, By designing different geometric parameters of the casing, using impeller static pressure ratio and diffuser static pressure recovery coefficient as evaluation standard, the effect of different geometrical parameters of back groove width on the compressor performance was compared to choose an optimized parameter.Study and research in this paper resulted in deepening understanding of numerical simulation on compressor flow, detail of the flow distribution, flow characteristics and formation mechanism in the compressor was studied, the aerodynamic noise source distribution and the characteristics of spectrum and its mechanism were elaborated. Improved design of compressor focused on using SRCT, influence of different geometric parameters of the casing on the compressor performance was analyzed, improved design of the compressor in this paper provided a reference on improving compressor performance, widening compressor stable operation range.