Experimental Study And Numerical Simulation Of A Novel Fixed Valve Tray

Trayed column is an important type of gas-liquid contact equipments in the oilrefining and chemical industries. Thereinto, the fixed valve tray has been inwidespread use due to low pressure drop and perfect anti-blockage performances. Inthis work, a novel cross orthogonal fixed valve tray is suggested to attain a favorablespecific effective contact perimeter under a certain orifice area, and accordingly thehydrodynamic and flow field were analyzed by virtue of experiments andcomputational fluid dynamics (CFD) simulation.The experiments, by use of air-water system, were carried out in a stainless steelcolumn of1200mm. The hydrodynamic performances, including pressure drop,entrainment, weeping and clear liquid height, were obtained under the variousoperation parameters (liquid weir load and superficial gas velocity) and structuralparameters of fixed valve tray (weir height, fractional orifice area and directions offixed valves). Besides, the corresponding correlation equations of these hydrodynamicperformances have been suggested on basis of experimental data as well.Simultaneously, three dimensional CFD simulations under the cases of single gasflow and gas-liquid flow were completed respectively based by means ofcomputational fluid dynamics software.During the singe gas phase simulations, three kinds of k model wereadopted. And the CFD model was verified on the base of comparison betweensimulated dry pressure drop and experimental data. At the same time, thecomputational cost was also taken into account under different turbulence models. Inaddition, the detailed gas flow field analysis were carried out by use of Realizablemodel, which presented higher accuracy and less computational cost, and thestructural optimizations were also attempted, such as changing the distances betweenvalves and the setup of auxiliary guiding orifices.As to the gas-liquid simulations, the gas and liquid phase, as two interpenetratingphases, were simulated in the Eulerian framework, and a mixture turbulence modelbased on Realizable equation was adopted for the two phases. Interactionbetween the two phases occurred via interphase momentum source was calculatedusing the correlations proposed by Krishna. The clear liquid heights determined by these simulations were in good agreement with the experimental data, and the validityof the CFD model for the fixed valve tray was proved. Additionally, the analysis onthe gas-liquid hold-up and velocity fields were carried out in detail and the furtherstudy related to the valve direction and auxiliary guiding orifices were also attempted...