为了研究微细通道壁面润湿性对过冷沸腾起始点（ONB）的影响,采用Cu Cl_2溶液刻蚀普通光滑表面微细通道得到超亲水表面微细通道,再用氟硅烷溶液修饰超亲水表面微细通道得到超疏水表面微细通道。以R141b为实验工质,在压力为170k Pa、质量流率302.7~417.2kg/（m~2·s）、热流密度2.17~29.9k W/m~2的工况下进行流动沸腾实验。结果表明：超疏水表面微细通道ONB点的过热度最低,普通光滑表面微细通道达到ONB点所需过热度最高;随着热流密度的增大,距离出口最近的测点最先开始沸腾,达到ONB点所需过热度也为最小;随着质量流率的增大,ONB点的过热度逐渐增大。本文选取了7种典型的ONB点处壁面过热度预测公式,将实验值与公式预测值进行对比,发现HSU模型的预测效果最好,对光滑/超亲水/超疏水表面微细通道ONB过热度预测平均绝对误差（MAE）值分别为13.1%、20.8%和21.5%。为了更好地预测具有特殊润湿性表面的ONB过热度,引入表面能参数对HSU模型进行修正,预测精度大大提高。
Experiments were conducted to study the effect of wettability on onset of nucleate boiling（ONB）. The super-hydrophilic surface micro-channel was obtained by etching smooth surface micro-channel with Cu Cl_2 solution and then modifying with fluorosilane solution subsequentially. At the pressure of 170 k Pa,flow boiling experiment was carried out with R141 b,the mass flow rate is 302.7—417.2 kg/（m~2·s） and heat flux is 2.17—29.9 k W/m~2. The experimental results showed that the wall superheat at ONB on super-hydrophobic surface is the lowest,and the superheat on smooth surface is the highest,the nearest measurement point from the exit boiling at first,and wall superheat for ONB is also the minimal;the wall superheat for ONB increased with increasing of mass flux. Seven typical prediction formulas of wall superheat at the ONB were selected. The experimental results were compared with the predicted ones. It is concluded that the HSU＇ model has the best predictive values. The predictive values for superheat at ONB on the smooth/super-hydrophilic/super-hydrophobic surface micro-channel were studied. The mean absolute error（MAE）is 13.1%,20.8% and 21.5% respectively. In order to better predict the wall superheat at ONB on special wettability surface,the surface energy parameters were introduced to modify HSU＇ model,and the prediction accuracy was greatly improved.
Chemical Industry and Engineering Progress
onset of nucleate boiling（ONB）