Numerical Simulation Of The Flow Field In A Countercurrent Gas-liquid Scrubber

The nozzle of traditional counter current gas-liquid scrubber usually has the inner wall with the swirl groove to ensure that the gas-liquid counter-current collision of axial momentum and tangential momentum,but its internal structure is to complex to clean up and the distribution of the liquid is uneven.This paper based on the experimental results to carry on a simulation on a nozzle with three-inlets.By using RNG k-ε turbulence model and Euler two-fluid multiphase model,the flow characteristics of the countercurrent-crossflow gas-liquid imping scrubber is presented and the computed results were validated via experiments.The velocities of the two phases,the turbulence intensity,the pressure drop,the local gas hold up distribution were analyzed as the key date.The results show that the streamlines in the gas-liquid impact area are quite fierce and complex-distributed,forming a large number of vertexes.The axial velocities of the two phases slow down but the tangential&radial velocities of the two phases varied rapidly and assume high values.Gas hold up distribution is stable between 0.8 and 0.9.The turbulence intensity is larger than 1%.The mass concentration of particles in the region is low,ranging from 0.2τ to 0.5τkg/m~3(tis the coefficient of characteristic concentration),and the particles are evenly distributed in region.The flow field characteristics of the scrubber under different operating conditions were simulated and analyzed in detail.The results shows that if the gas/liquid mass flow rate in the scrubber is constant,the flow pattern changes from column to type of bowl as axial and tangential liquid mass flow ratio decreases.With an increasing of axial and tangential liquid mass flow ratio,the variation of the volume fraction of the effective mass transfer area in the total flow field first increases and then decreases,a maxiumum appears around 0.0096.On the other hand,with an increasing of liquid/gas mass flow rate,it increase first and then decreases too,a maximum appears around 0.66.In order to optimize the structure of the scrubber nozzle,the nozzle with different nozzle diameter and different tangential angle of inlet was simulated.The results shows that when the diameter of the nozzle is 8 mm,tangential angle to the liquid inlet is 60°,the effect of gas-liquid mass transfer reaches an comparaticvely desirable condition.