Study On Flow And Heat Transfer Characteristics Of Corrugated Cooling Channel In Traction Converter

With the improvement of the running speed of the train,the power of the train is constantly increasing,and the power of the converter is also constantly increasing,which leads to a sharp increase in the heat of the converter.Moreover,with the rapid development of electronic and power component technology,the development direction of electronic and power equipment is basically tending to integration,high density and miniaturization.The traction converter,the core device of the EMU,belongs to the integration module,which leads to a sharp rise in the heat flux of the converter.The high temperature of electronic components will affect the service life of the converter and the safe and stable operation of the train.In order to avoid the damage caused by excessive temperature,it is necessary to study the cooling channel structure of traction converter,so as to improve the heat transfer capacity of the cooling channel.This paper mainly studies the cooling channel structure of the train traction converter.Firstly,by simplifying the structure of the water-cooled radiator of the traction converter reasonably,a three-dimensional geometric model is built,and the boundary conditions and inlet conditions are set up.Then,the simulation software Icepak is used to simulate the parallel water-cooled plate structure,and the flow and heat transfer characteristics of the parallel water-cooled plate structure under different working conditions are analyzed.In order to improve the heat transfer capacity of the cooling channel,the channel structure was optimized based on the parallel water cold plate structure,that is,the corrugated surface driven by sine function,trapezoidal corrugated surface and triangular corrugated surface were added to the bottom surface of the parallel cooling channel.The flow and heat transfer characteristics of these new structures are studied and analyzed.It is found that corrugated surface can effectively improve the heat transfer performance of cooling channels.Finally,the effects of the geometric parameters(amplitude,wavelength,inlet velocity and heat source spacing)on the flow and heat transfer characteristics of the sinusoidal corrugated cooling channel and the flow and heat transfer performance of the corrugated cooling channel and the aperiodic corrugated cooling channel under the quadratic function are analyzed.The main conclusions of this paper are as follows:(1)Firstly,Icepak was used to simulate the structure of the parallel water cooling radiator.According to the simulation results,the flow and heat transfer characteristics of the parallel cooling channel were studied and analyzed.Then,based on the parallel cooling channel design optimization,the sinusoidal corrugated cooling channel,triangle cooling channel and trapezoidal cooling channel are built,and the three kinds of corrugated cooling channels are compared and analyzed by simulation.At the same flow rate,the heat dissipation performance of sinusoidal water-cooled plate structure is better than that of triangle water-cooled plate structure and trapezoidal water-cooled plate structure,and the trapezoidal water-cooled plate structure has the worst heat dissipation performance.However,the pressure loss of sinusoidal structure is the largest,followed by that of trapezoidal structure,and that of triangular structure is the least.By changing the inlet velocity of the coolant and the distance between the heat source,it is found that with the increase of the inlet velocity of the coolant and the distance between the heat source,the heat dissipation effect of the water cooling plate will be better and better.(2)The influence of the geometrical parameters of the corrugated surface on the heat transfer and total pressure drop of the sinusoidal corrugated cooling channel was studied.The results show that the heat transfer performance of the corrugated cooling channel is improved with the increase of the corrugated wave amplitude,and the pressure loss at the inlet and outlet is increased.The heat transfer factor of the corrugated channel increases first and then decreases with the increasing amplitude,and the values are all greater than 1.When the wave amplitude is 12 mm,the heat transfer factor reaches the maximum value.This indicates that the corrugated cooling channel has the best comprehensive performance.(3)As the wavy wavelength increases,the heat transfer performance of the wavy channel decreases and the pressure loss decreases.The heat transfer factor of corrugated cooling channel increases with the increase of wavelength,and its value is all greater than 1.(4)Finally,two kinds of corrugated cooling channel structures different from sinusoidal corrugated cooling channel are designed: corrugated cooling channel under quadratic function and aperiodic corrugated cooling channel.The pressure loss of these two structures is smaller than that of the sinusoidal corrugated cooling channel,but the heat transfer capacity of the sinusoidal corrugated cooling channel is better than that of the corrugated cooling channel structure and the aperiodic corrugated cooling channel structure under the quadratic function.