A comprehensive study of direct-contact condensation heat transfer for turbulent, counter-current, liquid/vapour flow in a nearly horizontal channel at high pressure (i.e. 5 MPa) has been carried out based on Direct Numerical Simulation (DNS) and highly-resolved Large Eddy Simulation (LES) approaches. To simulate the two-phase flow situation, driven in this case by a constant pressure gradient, a single set of Navier–Stokes equations, coupled with an enthalpy conservation equation, have been employed. The interfacial mass transfer, seen in this case to be dominated by condensation, has been calculated directly from the heat flux at the liquid/vapour interface. To investigate the effect of condensation on the turbulence phenomena, and vice versa, cases have been considered involving two friction Reynolds numbers: namely \(Re_{*}=u_{*}h/\nu =178\) and \(Re_{*}=u_{*}h/\nu =590\) (\(u_{*}=(h\varDelta P/\rho )^{1/2}\)). At the lower Reynolds number, three levels of water subcooling—0 K, 10 K and 40 K—have been investigated. The use of water subcooling of 0 K has enabled the validation and verification procedures associated with the numerical approach to be compared against experimental and numerical data reported in the literature. The choice of the maximum degree of water subcooling is dictated by the need to justify the periodic boundary conditions applied in this numerical study. In the simulation for the higher Reynolds number, only the case of 10 K subcooling has been included, as a consequence of the very high computation effort involved. A detailed statistical analysis of the DNS and LES data obtained from the application of the well-known wall laws has also been assessed. In the vicinity of the liquid/vapour interface, the characteristics of the turbulent motions appear somewhat diverse, depending on whether the interface is basically flat or wavy in character. For a flat interface, some damping effect of the presence of the interface on the turbulence intensity has been observed, a feature which becomes enhanced as the level of liquid subcooling is increased. In the case of a wavy interface, the damping effect is predicted as considerably less pronounced.

基于直接数值模拟（DNS）和高分辨率的高分辨率，对近水平通道高压（即5 MPa）下湍流、逆流、液汽流的直接接触冷凝传热进行了综合研究。大涡模拟 (LES) 方法。为了模拟在这种情况下由恒定压力梯度驱动的两相流动情况，我们采用了一组 Navier-Stokes 方程和焓守恒方程。在这种情况下，界面传质以冷凝为主，直接根据液/气界面处的热通量计算得出。为了研究凝结对湍流现象的影响，反之亦然，考虑了涉及两个摩擦雷诺数的情况：即\(Re_{*}=u_{*}h/\nu =178\)和\(Re_{*}=u_{*}h/\nu =590\) ( \(u_{*}=(h\ varDelta P/\rho)^{1/2}\)）。在较低的雷诺数下，已经研究了三个水平的水过冷度——0 K、10 K 和 40 K。使用 0 K 的水过冷使得与数值方法相关的验证和验证程序能够与文献中报告的实验和数值数据进行比较。最大水过冷度的选择取决于证明本数值研究中应用的周期性边界条件的合理性。在较高雷诺数的模拟中，仅包括 10 K 过冷的情况，因为涉及的计算工作量非常大。还评估了从应用众所周知的墙壁定律获得的 DNS 和 LES 数据的详细统计分析。在液/气界面附近，湍流运动的特征显得有些多样化，这取决于界面是基本平坦的还是波浪形的。对于平坦界面，已经观察到界面的存在对湍流强度的一些阻尼效应，随着液体过冷度的增加，这一特征变得增强。在波状界面的情况下，阻尼效应预计会显着降低。