Simulation Of Flow And Heat Transfer,Abrasive Jet Machining Of Wavy Microchannel

The integration of electronic components is increasing,which will directly lead to the heat flux increase sharply,and the thermal failure has become the main reason for the reliability reduction of microelectronic systems.Microchannel radiators have become the research focus because of the large heat transfer per unit area and high heat transfer coefficient.In order to design a microchannel radiator with better heat transfer performance,the simulation models of rectangular and V shaped cross-section wavy channels are established.By observing the changes of Dean vortex position,quantity,size and persistence length in the channels,the influences of amplitude A,wavelength λ,velocity u on the heat transfer performance and flow performance in rectangular and V shaped cross-section wavy channels are analyzed,and the influences of different amplitude A,wavelength λ and channel number N on the comprehensive performance are also analyzed under the same pump power.The changing rules of Nusselt number(Nu),thermal resistance(R),pressure drop((35)P),pump power and comprehensive performance PEC of microchannels are obtained.Therefore,the parameters such as amplitude A and wavelength λ are optimized,and the channel type and number with the best comprehensive performance are selected.The abrasive jet machining models of rectangular and V-shaped cross-section channels are established by using ABAQUS,The main research contents are as follows:(1)Firstly,the model is established according to the boundary conditions set by Shah and Qu et al,and the correctness of this simulation model is verified according to the theoretical results and simulation results.Then,the grid independence is verified.Finally,two simulation models of rectangular and V-shaped cross-section wavy channels are established.(2)Firstly,the influences of amplitude and wavelength on the heat transfer and flow performance of rectangular and V-shaped cross-section wavy channels are analyzed,and compared with straight channels.The fundamental reasons for the change of heat transfer performance of rectangular and V-shaped cross-section channels are further explored.Then,parameters such as A and λ are optimized under the same pump power.Rectangular and V-shaped cross-section wavy channels reaches the best comprehensive performance when A=0.3 mm and λ=5 mm.(3)After the amplitude A and wavelength λ are determined,the influence of flow velocity on the heat transfer performance and flow performance of the channel are studied.With the increase of flow velocity u,the heat transfer performance is gradually improved,and the pressure drop also increases.Under different A or λ,the comprehensive performance of microchannel is the best when u=1.4m/s for rectangular cross-section wavy channels,and the comprehensive performance is the best at different fluid velocities for V-shaped cross-section wavy channel.(4)In order to achieve the best heat dissipation effect of microchannel heat sink,rectangular or V-shaped cross-section wavy channels are arranged on the same size heat sink under the same pump power,and the influencing factors of heat transfer performance change are explored,and the cross-sectional shape of microchannels and the channels number N are optimized.In this simulation scheme,rectangular corrugated channels have the best heat transfer performance,and the channels number is N=10.(5)The simulation model of abrasive jet machining channel is established by using ABAQUS,and the transient process of abrasive jet machining is analyzed.After adjusting the process parameters,the rectangular cross-section channel is machined,and the machining schematic diagram of V-shaped cross-section channel is given.