A problem of evaporative buoyancy-thermocapillary convection in a two-phase system of binary media is studied. Characteristics of a joint steady flow of evaporating fluid and gas in a narrow plane horizontal channel are analyzed on the example of aqueous ethanol solution and mixture of the nitrogen with the ethanol vapor. The influence of solutal effects related to changes in the ethanol concentration in the liquid mixture is scrutinized. New exact solution of thermosolutal convection equations is constructed in the framework of a two-sided model based on the Oberbeck–Boussinesque approximation. The model used implies the presence of the liquid–gas interface admitting evaporation where surface phenomena play a key role. The testing of problem statements is performed in order to determine feasible closing relations. A correct problem statement is proposed that provides acceptable accordance with known experimental data concerning both the working liquid properties and possible pattern of the bilayer flows. Non-linear character of dependence of evaporation rate on the concentration of the aqueous solution is established. The solution predicts the decrease in evaporation rate due to the diffusion resistance effect for some compositions of the liquid mixture, thereby it is shown the possibility of control of the heat exchange parameter by means of the choice of the working fluid compound. The results obtained can be useful under developing the experimental methods for exploration of the interfacial effects in multicomponent fluids.

中文翻译：

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二元混合物双层系统中浓度对蒸发对流影响的数学模型

研究了二元介质两相系统中的蒸发浮力-热毛细管对流问题。以乙醇水溶液和氮气与乙醇蒸气的混合物为例，分析了窄平面水平通道内蒸发流体和气体共同稳定流动的特性。研究了与液体混合物中乙醇浓度变化相关的溶液效应的影响。在基于 Oberbeck-Boussinesque 近似的双面模型框架中构造了热溶质对流方程的新精确解。使用的模型意味着存在允许蒸发的液-气界面，其中表面现象起着关键作用。对问题陈述进行测试是为了确定可行的封闭关系。提出了正确的问题陈述，该陈述提供了与工作液体特性和双层流的可能模式相关的已知实验数据的可接受的一致性。建立了蒸发速率对水溶液浓度依赖性的非线性特征。该解决方案预测了由于液体混合物的某些成分的扩散阻力效应而引起的蒸发速率的降低，从而显示了通过选择工作流体化合物来控制热交换参数的可能性。所获得的结果可用于开发探索多组分流体中的界面效应的实验方法。