矩形毛细微槽横截面上气液分界面形状理论分析

ANALYTICAL SOLUTION FOR THE LIQUID-GAS INTERFACE IN THE CROSS SECTION OF RECTANGULAR MICRO CHANNELS

对背面有热流输入的矩形毛细微槽群横截面上的气液分界面形状进行了理论分析,在一定条件下对Wayner蒸发模型进行简化,根据等壁温条件推出蒸发薄液膜区域热流密度近似为定值,通过流体动力学理论推导出了微槽横截面薄液膜区域液膜厚度变化的关系式,并与Wayner蒸发模型的计算结果进行了比较。进一步提出了全新的交界线区域长度的判定方法,根据蒸发薄液膜区域总换热量计算得到蒸发薄液膜区域的长度,交界处接触角,以及固有弯月面区域的曲率半径,从而最终得出了微槽横截面整个气液分界面的形状曲线,理论分析表明:槽宽、热流密度、过热度等因素对蒸发薄液膜区域长度、接触角以及固有弯月面曲率半径等参数有较大的影响。

The liquid-gas interface in the cross section of rectangular micro channels is studied theoretically. Wayner＇s evaporation model is simplified and the heat flux in the thin film region is found to be a constant value approximately. A new determined method for the contact line is proposed. The analytical expressions are presented for the length of the thin film, the contact angle and the curvature of the intrinsic meniscus, which are all influenced by the width of the micro channels, heat flux and superheat temperature.