Numerical And Experimental Investigation Of Film Flow Resonance Characteristic Over Corrugated Plates

Resonance phenomenon occurs when film flows over a fixed corrugation under certain conditions.In this study,we research the factors related to the resonance phenomenon by numerical simulations and experiments,and we propose the resonance section.The numerical simulations are performed with the open source software OpenFOAM,and the experiments are conducted by the particle image velocimetry(PIV)method.The results demonstrate that:The numerical models are verified by the comparison of simulation results and experimental results.The oscillation of gas-liquid interface reaches maximum when the resonance phenomenon happens.Relative amplitude and free surface length reaches maximum at resonance point.The variations of average liquid film thickness have a turn around the resonance point.The resonance section is proposed by the study of bottom eddied.In this section,the oscillation of the film surface is enhanced and bottom eddies are suppressed.The upper and lower bounds of the resonance section correspond to the two inflection points of free surface amplitude.The increase of average liquid film thickness is slight and even decreases.The speed of the reflux region is much smaller than that other regions,and there is an order of magnitude difference between them.The normal velocity intensity of the free surface is increased.The factors affecting the resonance point are then studied.The effect of gas phase velocity on the resonance phenomenon of film flow is limited in the gas velocity range without liquid flooding.The height of corrugation does not move resonance point,but the relative amplitude gets larger with the rise of corrugation height.If corrugation number is more than 3,the flow is stable and not changed.The inclined angle of corrugation affects resonance point significantly.If the inclined angle is big,the resonance phenomenon tends to happen in a low Reynolds number.There is a linear relationship between surface tension and resonance point.The resonance Reynolds number decreases with the increase of dynamic viscosity.The value of the resonance point is approximately linear to the reciprocal of the dynamic viscosity of 0.8.The value of the resonance point is approximately linear with the reciprocal of the square root of the fluid density.The empirical formulas for the relative amplitude at resonance point and surface tension,dynamic viscosity and density and resonance Reynolds number are obtained.In industrial production,to find a specific point is too difficult.This study shows that the flow parameters related to the mass transfer are enhanced in a region.For the selections of operating conditions in industrial film flow applications,this research can provide a theoretical basis.