基于纳米磁流体微通道内流动换热性能研究

Study on flow and heat transfer characteristics in magnetic nanofluids microchannels

为探究磁场强度和肋片高度对微通道内Fe_(3)O_(4)-H_(2)O纳米磁流体流动换热性能的影响,采用数值模拟的方法,以开放式间断微通道热沉为研究对象,在雷诺数为200到500之间展开数值模拟研究,模拟微通道内流体工质流动换热过程。结果表明:进出口压降随雷诺数的增大而增大,且随着磁场强度的增大,压降的增大趋势愈显著;微通道的换热性能随着磁场强度的增大,呈现出先增大后减小的趋势;通过增加肋片高度,可以有效的提高热沉的传热性能。研究发现,开放型微通道综合换热性能优于封闭型,在所研究的参数范围内,微通道肋片高度达到0.9 mm时,综合换热性能和均温性最佳。

In order to explore the influences of magnetic field intensity and fin height on the heat transfer characteristics of Fe_(3)O_(4)-H_(2)O nanomagnetic fluid flow in the microchannel,a numerical simulation method was used to simulate the heat transfer process of fluid working medium in the microchannel with the open discontinuous microchannel heat sink as the research object,and the Reynolds number was between 200 and 500.The results show that the pressure drop at the inlet and outlet increases with the increase of Reynolds number,and the increasing trend of the pressure drop becomes more significant with the increase of the magnetic field intensity.The heat transfer characteristics of the microchannel increases first and then decreases with the increase of the magnetic field intensity.The heat transfer characteristics of heat sink can be effectively improved by increasing the fin height.It is found that the comprehensive heat transfer characteristics of the open microchannel is better than that of the closed microchannel,and the comprehensive heat transfer characteristics and temperature homogeneity is the best when the fin height of the microchannel reaches 0.9 mm in the study range.