Pulse And Vibration Impact On Car Radiator Heat Transfer And Resistance

Radiator is an important part of engine cooling system, the function of it directly affects the engine working condition. At present, many researchers use experiment and CFD simulation technology to research on it. The structure of louver fin radiator is optimized, and obtained satisfactory result, but the optimization of the radiator structure is unable to meet the requirement of today’s performance of radiator. Pulse strengthening heat transfer technology and vibration strengthening heat transfer technology are introduced into the shutter fin radiator study, in order to improve the performance of the radiator.Firstly, this paper studies the different forms of car radiator, put forward the key methods and techniques to improve the performance of radiator, and analyzes strengthen heat transfer mechanism. This paper introduces the knowledge of CFD numerical simulation, and presents a conventional numerical simulation operation process.Then, the physical model of the radiator is established and imported to the front of the simulation software. Choose different models according to different Reynolds number. Pulse strengthening heat transfer uses UDF(user-defined functions) function to description the sine pulsation inlet, simulate the pressure field and velocity field under different working conditions. Vibration strengthening heat transfer uses Table File function to description the sine vibration inlet, simulate the pressure field and velocity field under different working conditions. According to the result of simulation to calculate the resistance factor and heat transfer factor, and by using the comprehensive evaluation factor to evaluate car fin radiator performance. Result shows that:(1) the pulsation wind speed and fin vibration can effectively improve the heat transfer coefficient;(2)when the wind is pulsation, the comprehensive evaluation factor first increases and then decreases with the increase of frequency and amplitude, when the pulsation wind speed is 6 m/s, its comprehensive evaluation facto is best;(3)when the radiator fin is vibration, the comprehensive evaluation factor first increases and then decreases with the increase of frequency and amplitude, under the influence of vibration frequency factors, steady wind speed is 6 m/s, the comprehensive evaluation factor is best; under the influence of vibration amplitude factor, steady wind speed is 8 m/s, the comprehensive evaluation factor is best.