Numerical Simulation Of The Falling Liquid Film Flowing Progress On Split Wall With Functional Coat

Wild atmospheric haze raise energy saving and emission reduction to a whole new level. Heat pump, which can collect industrial waste heat and promote the use of energy resources comes into sight of everybody. Absorbor is the core equipment of heat pump, which plays an important role in promoting conversion efficiency of resources. Vertical flat absorbor has wide application prospect as it has small floor space and its simple construction. Researching the falling liquid film flow mechanism inside vertical flat absorbor to promote the efficiency of heat pump has become a hot topic right now. This paper hopes to add hydrophobic wall on the falling liquid film flow wall, which will be a functional combined wall using numerical simulation software to research its influence to falling liquid film flow process.2D vertical flat falling film flow model is built, and VOF method is used to vertifies the definition of the minimum spray density formula, Simulation can be divided into two parts by the minimum spray density, one is smaller, and one is bigger, to compare the falling liquid film flow behavior with and without the coated region:When the spray density is smaller, dry spots appear on the wall, the falling liquid film which flows to the coated region part aggregates there with eddies inside the film, this will be favorable to heat and mass transfer; In practical industrial operating processes, the spray density is bigger, the film will cover the wall fully, and there are no eddies inside the film, then waveform of film when flowing process is steady with and without the coated region can be analysised comparatively, combining with the coefficient of variation which comes from the turbulence to analysis the velocity inside film for demanding results.As the 2D model simplifies the dimension of the width of the liquid inlet, which makes it impossible to judge the wave fluctuations, so a 3D vertical wall with functional coat falling liquid film flow model is built referring to existing references. The simulation results are in accordance with the 2D model results, and the turbulence of the models with and without coated region can be compared.The velocity component which is perpendicular to the falling liquid film flow direction is different when the flow is steady, and the situation with the coated region is bigger, and so do the coefficient of variation in both 2D and 3D model, illustrating the promoting role in strengthing turbulence. For the 2D model,70° (without coated region)、100°、120°、150° contact angles are set, the length of the coated region are Omm(without coated region)、5mm、 10mm、15mm, which get the same results. But new discoveries tell that it is not the bigger the contact angle and the longer the length of the coated region, the better the turbulence consequence. Seeking the best coated region contact angle and the best length for a given model remains to be further research.The foundation of the 2D and 3D models are vertified by Nusselt theory, and the simulation results are in accordance with the existing experimental results, which illustrates the models of this paper are correct.