基于Origin的酒精溶液表面张力数据处理

Data Processing of Surface Tension Based on Origin for Ethanol Solution

当不同浓度酒精和水的混合蒸汽凝结时,由于凝结液各处表面张力的差异,会产生Marangoni效应,出现类似于珠状的凝结形态,其传热系数与混合蒸汽的摩尔浓度及凝结温度有着密切的关系。为进行传热系数的理论计算,需知不同浓度和温度表面张力的数值。应用吊环法测量了不同浓度和温度酒精溶液的表面张力,测量溶液的温度范围为18～50℃,浓度0～2.034 7 mol/L。基于希什斯夫斯基模型,使用Origin非线性曲线拟合功能,按最小二乘曲线拟合方法拟合了不同酒精溶液浓度的σ-c关系。将温度量引入σ-c关系式,得到考虑浓度和温度的希什斯夫斯基模型计算公式。在中低浓度范围内,计算值与实验值的误差在-1%～5%。

When water-ethanol mixture condenses on a surface,one observes that the liquid condensate rises locally and eventually forms many droplets on the film due to different surface tensions,which is referred to as Marangoni condensation.The heat transfer coefficients depended closely on the vapor concentration and temperature.The surface tension of ethanol solution for different concentration and temperature was needed if theoretical calculation for heat transfer coefficient was to be conducted.Surface tension of different ethanol concentrations and temperatures were measured by ring method within the temperature range of 18～50℃ and the mole fraction rang of 0～2.0347.For different concentrations of ethanol solution,the relationship between surface tension and concentration is fitted according to the least-square method based on Szyszkowski model.And the fitting is carried out by using non-linear fitting function of origin.When the temperature is introduced,a Szyszkowski model calculation formula which takes concentration and temperature into consideration,is obtained.The calculated value is in good agreement with experimental results under medium-low concentration,and the maximal error is within-1%～5%.