Study On Scale Effect And Full-scale Forecasting Model Of Submerged Oil Leakage From Damaged Double Hull Oil Tanker

The Maritime transportation of crude oil is an important mean of China’s crude oil imports.Under the strategic background of Petroleum Strategic Reserve and Marine Silk Road,Crude oil shipping is increasing year by year.In the next few years,The Maritime transportation of crude oil will face more serious leakage risk due to the channel congestion.The social demand of the accurate prediction and effective control of oil leakage becomes more and more urgen.At present,the scale model is mostly adopted to simulate crude oil spill process and research its law in the academic circles,based on this foundation,some prediction models were proposed.However,due to the existence of scale effect,the oil leakage prediction models and its leaking law are not accurate enough.Hence,the first thing is to solve the problem of scale effect,and the more precise forecast modal of oil leakage will be put forward based on that.In this paper,the study is carried out with CFD simulation based on similarity theory and fluid dynamics,focus on the research of scale effect and prediction model,mainly completed the following parts: Firstly,the causes of scale effect are preliminarily analyzed from the perspective of dynamic similarity.Based on froude model,numerical simulation of oil leakage are carried out with different scale ratio.According to the similarity relationships of oil leakage feature parameters between scale model and prototype,results from scale model with different scale ratios are extrapolated to large-size prototype.The law of oil leakage in different stage are discussed,the cause and influence mechanism of scale effect are analysised.Secondly,the theoretical similarity criteria and similarity function relationship of oil leakage have been obtained by using dimensional analysis,a new method of scale model was put forward,as well as a new dynamic mechanism prediction model by means of numerical simulation.The accuracy of the new prediction model is verified by comparing with the existing dynamic mechanism model and the prototype results.Thirdly,In the study on prediction model of oil leakage,scale models are established according to Reynolds similarity、Froude similarity and other similarity.To get enough data,a group of numerical simulation of oil leakage with which different density and viscosity are conducted.Based on dimensional analysis,the multiple quadratic nonlinear regression model between non-dimensional numbers and oil leakage rate is established.Predefined function of MATLAB is used to solve the parameters of the nonlinear regression model and verification.By utilizing numerical simulation methods,the numerical experiments were carried on with different scale ratio,and the mechanism of oil leakage is deeply discussed.The results of this study have some guiding significance to the design of scale model test,and provide the theories foundation for the accurate prediction and effective control of oil leakage.