Low Frequency Pulse Strengthening Heat Transfer Research

In order to study pulsating intensified heat transfer technology,numerical simulation of the flow and heat transfer of pulsating flow is carried out in the plate heat exchanger plate.The influence of flow rate,pulsation frequency and pulsation amplitude on these is explored.In this paper,the flow channel between plate heat exchanger plate is modeled.Mainly to the following conclusions:1.The fluctuation frequency has no effect on the inlet velocity and the speed of the outlet velocity.The fluctuation amplitude of inlet and outlet pressure increases with the increase of pulsation frequency and pulsation amplitude;2.With the increase of the fluctuation frequency,the intensified convection heat transfer efficiency of the pulsating flow decreases rapidly and then increases slowly;3.With the increase of pulsation amplitude,the intensified convective heat transfer efficiency of the pulsating flow is increasing.Then I designed a set of electromagnetic valve as an experimental device for water hammer pulsation generator.The pulsating flow generated by the opening and closing of the solenoid valve in the upper reaches of the cooling water of the plate heat exchange.The total heat transfer coefficient of plate heat exchanger is used to characterize the heat transfer effect.The experimental results show that:1.In the turbulent stage,the effect of pulsation frequency on heat exchange is the strongest;2.Under various experimental conditions,there is the optimal pulsation frequency f_o,whose value is related to fluid flow state,pulsation amplitude and other factors.3.Increase the pulsation amplitude to improve the heat transfer ability of pulsating flow.However,in some cases,the enhanced heat exchange effect of pulsating flow under higher pulsation amplitude is reduced;4.The pulse frequency and duty ratio determine the pulsating form of the pulsating flow in the same working condition;5.The pulsating flow has a certain strengthening effect.