Numerical Simulation Of Gas-liquid Two-phase Flow In The Annular Gap Scrubber

In metallurgy industry,especially in iron and steel industry, Bischoff scrubber has been adopted by many large-scale blast furnace because of the high performance on top pressure control and well gas cleaning ability. On the other hand, The Top Gas Pressure Recovery Turbine (so called TRT system) is easily controlled if the Bischoff system is used. It has been proved with the high efficiency if the high pressure blast furnace, Bischoff system and the TRT system were jointly operated. It is not only to upgrade the efficiency of the blast furnace but also conduce to environment protection by use of the Bischoff system. So there are very important practical value and academic meaning to research the scrubber's inner gas-liquid two-phase flow.The pressure drop of the annular gap scrubber of the blast furnace is important basis of inner furnace pressure control. In the annular gap scrubber, there exists complicated three-dimensional compressible flow associated with the two phase flow and heat transfer between gas and water particle. In the paper, the gas-liquid two phase flow and heat transfer process in the annular gap scrubber were analyzed and the corresponding physical and mathematical models were proposed. At first, an one-dimensional homogeneous diffusion model for an AGE unit was proposed and solved by employing four order Runge-Kuta method, the pressure drop profile varied with the inlet gas volume was obtained and analyzed. Then physical and mathematic models of the three-dimensional, compressible and gas-liquid two-phase flow in the annular gap scrubber were proposed. The computational model was discretized with hybrid meshes into multi-block zones in the preprocess software Gambit, and was solved numerically by employing the Fluent solver. The turbulence in the flow was treated by using the (RNG)k-εturbulent model, the convection term in the governed equation was discretized with the second order upwind scheme, and the diffusion term was discretized with the linear interpolated scheme. The coupled computation of pressure and velocity variable was completed with the SIMPLE algorithm. The motion of the water particles in the annular gap scrubber was simulated by the Lagrangian discrete phase model, meanwhile the interaction effect between two phases was taken into account. Due to the difficulty of convergence in the iterative computation of compressible and two-phase flow, the lower sub-relaxation factor(ω=0.1~0.2) as well as the method of gradually increase of mass flow rate were adopted, with a view of...