Numerical Simulation Of Smoke Diffusion For Semi-submersible Platform

With the rapidly tendency of the oil and gas exploitation to deepwater areas, the semi-submersible platform has been widely used. Being one of the principal equipments of a semi-submersible platform, the main engine discharges large amount of high temperature exhaust gas when it is working. On condition that the exhaust gas is improperly diffused in wind, the temperature around the working and living areas may increase and the security of workers and the stability of the equipments may this deteriorate. As a result, precise prediction of temperature and effective control of exhaust gas diffusion is of great significance.A CFD (Computational Fluid Dynamics) simulation of the exhaust gas diffusion around a Semi-Submersible Platform under various wind conditions is described in this paper. With full consideration of the particularity of jet flow, a sensitivity analysis method is used in the defining of dimensions and boundary conditions. In the paper, the turbulence model, species transport model, the buoyancy-drive model, which are involved in the CFD model, are all introduced, together with their relative numerical algorithms. In addition, four typical diffusion patterns are concluded according to the simulation results.Under the wind of some particular velocities, the temperature around air-inlets or in the moon pool may arise sharply. Feasibility studies are carried out for three temperature lowering schemes, including a pray cooling system, an extension of the rear part of deck and an alteration of the location of exhaust-pipes. This feasibility study may provide guidance for the designers and manufacturers. In terms of the simulation of water spray, the interaction between the continuous phase of air and the discrete phase of water spray is simulated based on the Euler-Lagrange method.