| With the development of industry, energy and environmental pollution problem hasbeen concerned by the people. Energy saving and emission reducing became one importantissue, many domestic and foreign scholars studied the issue. Reducing the resistance of shipcan effectively decrease energy consumption, meanwhile it can improve ship’s speed. It hashigh value in economy and military. So how to reduce the ship resistance effectively has beena urgent problem to solve by domestic and foreign scholars.Micro-bubble drag reduction technology could decrease frictional resistance, and it wasproved well in the trial. Micro-bubble drag reduction technology had developed for a longtime and had vast prospect. But domestic and foreign scholars were always pursuingnumerical method which is more accurate.The plate is numerical simulated as a simplified numerical model in this paper. Theinfluence of bubble size to the resistance reducing was analyzed, and Eulerian multiphasemodel’s optimal model, interphase drag model was applied. The k-εepsilon realizableturbulence mode was selected in three kinds K epsilon turbulence model and generalresistance of drag model was selected in the four drag model. The result showed the Eulerianmultiphase model was more reliable on grid size than other models, and reducing the size ofbubble can increase the drag reduction efficiency. Bubble size was0.00005m in this paper.On base of the conclusion of plate model,the cargo ship model was taken as a numericalmodel. It was calculated and analyzed to get optimal turbulence model, interphase dragmodel and grid division in Eulerian multiphase models. The influence of ship’s speed,gasinlet velocity and gas concentration to the drag reduction effect was analyzed in foursituations. The volume fraction of bubble in the hull deck was decreased and the efficiency ofdrag reduction was improved when the ship’s speed increased. During the low ventilationvolume, the drag reduction efficiency near the jet orifice was not the highest. The dragreduction efficiency would decrease when the distance to the jet orifice increased, but theventilation volume must reach the critical velocity. Critical velocity would change if theship’s speed, gas inlet velocity and gas concentration changed.Eulerian multiphase models and mixture multiphase models were numerical simulatedand analyzed. The calculation result of Eulerian multiphase models was more accurate. |
