Research On Wake Fraction Estimation Of Full Form Ships With Single Screw

Because of the consumption of global fossil energy and the pollution to environment,IMO put forward higher requirements on ships' energy-saving. If Chinese ship industry wants to reach the new standard as soon as possible and gain international market share in the future,a clear understanding on distribution of ship energy consumption is necessary and we can develop efficient and high-performance ships based on it. In powering performance prediction,compared to experiment and CFD method,estimation method is widely used in preliminary design stage of ships with advantages in computing speed and resource-occupation. In this process, wake fraction estimation was important and there is no sufficient method to full form ships with single screw by now which was researched in this paper. Some software like STAR CCM+, SPSS and Compaq Visual Fortran was used during the research.Most research in wake fraction estimation was old, the applicability should be doubted to full form ships developed in nearly twenty or thirty years. Calculate eight ships by twelve formulas, analysis the result and get recommendations. Predict powering performance and design propeller by different wake fraction, analysis the influence of estimation error.Based on experiment data of nine ships, choose eleven alternative variables initially,finally keep four explaining variables by stepwise. Divide data into small groups by Froude number, then make polynomial regression considering interaction items and get new wake fraction estimation formulas applied to full form ships with single screw.For 75000DWT bulk carrier, establish a computational domain and mesh by STAR CCM+, simulate model self-propulsion experiment by SST k-co turbulence model, MRF model and VOF method, deal with CFD results and predict powering performance, compare forecast values by different methods and get some conclusions.Compile powering performance prediction program of full form ships with single screw by Compaq Visual Fortran, input thirteen wake fraction estimation formulas and open characteristics of five common propeller series. The program was useful and meaningful in product design and research.