Numerical Analysis Of Pressure Drop And Heat Transfer Characteristics Of Rib Array In Microchannels

With the development of science and technology,mobile phones and computers and other electronic products gradually become light,miniaturized and intelligent,the heat dissipation problem has become one of the main factors hindering its development.Microchannel heat exchanger has been widely used to solve the heat dissipation problem of electronic products because of its advantages such as small volume,high reliability and strong heat transfer capacity.In this paper,the geometric and mathematical models of circular,rhomboid and droplet micro-ribbed heat exchangers with ribbed spacing of 0.75mm,1.2mm and 2mm were established,and the numerical caculations had been carried out.Under the conditions of water as the working medium,inlet temperature of 80℃,mass flow rate of 341～512kg/(m~2·s),and heat flux of 15～160W/cm~2,the analysis was carried out through numerical calculation,and the following conclusions were drawn:(1)From the point of view along the flow direction of the working medium,the fin shape has little influence on the trend change of the internal flow and heat transfer characteristics of the micro fin array,but the change of the rib spacing has a greater influence on it;under the same working conditions,the smaller the rib spacing is,the smaller the flow velocity is,the smaller the dryness is,the greater the pressure drop is,and the stronger the heat transfer force is;the diamond micro fin array has the largest dryness,the largest pressure drop,the worst heat transfer capacity,and the circular micro fin array has the largest heat transfer capacity The results show that the dryness,pressure drop and heat transfer capacity of the micro fin array are the minimum,while the flow velocity has little relationship with the shape of the fin;(2)The results show that the change of fin shape has little effect on the outlet dryness and pressure drop;at the same mass flow rate,with the increase of heat flux,the change of heat flux and fin spacing has a greater effect on the outlet dryness and pressure drop;at the same mass flow rate,with the increase of mass flow rate,the effect of fin spacing and mass flow rate has a greater effect on the outlet dryness and pressure drop;(3)At the same mass flow rate,with the increase of heat flux,the fin shape has a greater impact on the heat transfer coefficient;at the same heat flux,with the increase of mass flow rate,the change of fin shape and mass flow rate has a greater impact on the heat transfer coefficient;(4)According to the influence of different parameters on the heat transfer characteristics,a new heat transfer prediction correlation is obtained.The maximum error is 9.71%,which can basically meet the actual engineering needs.In conclusion,under the given conditions in this paper,the circular micro-ribbed heat exchanger with the rib spacing of 1.2mm is the best scheme to meet the requirements of micro-electronic heat dissipation,which has a guiding significance for engineering practice.