Heat dissipation and noise control optimization of combined cooling systems for double-deck EMUs
High-speed double-decker EMU has the problems of poor overall heat dissipation performance and serious noise pollution in the cooling system due to its compact internal space and high power of components.For this reason,the heat dissipation performance and noise control were optimized by numerical simulations and experimental study of the airflow field of the cooling system.By referring to the general air channel structure of the cooling system and the technical parameter requirements of the combined cooling system for double-deck EMU,its structure and size were preliminary calculated and designed.The structure of the heat exchanger and cyclone filter in the combined cooling system was simplified using a porous medium model and a multiple reference frame(MRF),respectively,and the airflow field was numerically simulated.The research results indicated that a local vortex at the fan's inlet would lead to a chaotic flow of air entering the fan and affect the effective work of the fan.The air volume flux of the system(2.96 m3/s)in the working environment was much lower than its design value(3.35 m3/s).Meanwhile,local vortices brought serious aerodynamic noise.In addition,the uneven distribution of air velocity at the inlet of the heat exchanger resulted in insufficient cooling capacity of the system.The air channel structure has been optimized to avoid the above issues.The flow area of three air channels at the inlet and outlet of the silencers were all adjusted.A diversion structure with a horn shape was installed in the transition section to improve the uniformity of air velocity in front of the heat exchanger.The arc-shaped silencers were fixed at the inlet and outlet of the cooling system to further reduce the noise.Results showed that the heat dissipation power from the water increased from 33.18 kW to 41.55 kW,the heat dissipation power of oil increased from 157.82 kW to 173.82 kW,and the weighted average noise value of the system decreased from 74.95 dB(A)to 72.21 dB(A)after optimizing the air channel structure.This study can guide the optimization design of cooling systems in similar engineering projects and is helpful to improve the ride feel and the economy of vehicle operation.
国家科技期刊平台
NSTL
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