| As the intensify of energy crisis and people’s concern about environmental problem keep growing,the tradition fuel automobiles,which not only cause severe air and noise pollution but also rely on oil energy,no longer meets the needs of time.In response to the call for sustainable development,new energy electrical automobiles have attracted researchers’ attention and walked into the spotlight of the development of automotive industry in the future.In order to further reduce the energy consumption of new energy cars,many studies have focused on the cooling and heating systems of the vehicles.Scroll compressor stands out with its unparalleled advantages,including high reliability,low vibration noise and high energy efficiency.Scroll profile,the fundamental constraint factor of scroll compressor performance,has become the top priority of domestic and foreign scholars.However,the current profiles optimization methods have common problems like complex model that lack of versatility,flexibility and intuitive design,and their optimization problems are often consider singleobjective.For these problems,the dissertation proposes a new optimization design method on the basis of particle swarm optimization and B-Spline principle,aiming at increasing the flexibility and intuitiveness of the optimization and design of scroll profiles.And the new profile obtained through this new method did have a better performance in stroke volume and volume-reduction ratio of gas-absorbing cavity.In the dissertation the major work and tasks are described as follow:(1)Aiming at the judgment methods of scroll profiles under the description of B-spline,the geometric characteristics and meshing principle of the scroll profile were analyzed,and the judgment method of the feasibility and applicability of the scroll profile was emphasized.In order to judge the profile by programming,the numerical judgment method is deduced in detail,and the discrete points of scroll profile and the evaluation formulas of its performance indexes under the expression of three degree quasi-uniform B-Spline are obtained.(2)To solve the profile optimization problem as a multi-objective optimization problem,the optimization model and constraint model of the profile are constructed and solved by swarm particle optimization algorithm.Aiming at the pain point that the basic particle swarm optimization algorithm is difficult to balance in global and local searching ability,oscillation inertia weight and mutagenic factor are introduced.The oscillating inertia weight enabled each particle to obtain the oscillating ability and be able to search in a larger feasible region;the mutagenic factor avoids the particles from homogenization in the later period of the optimization through mutation when updating.(3)Taking the circle involute as the initial shape,the feature vertexes are adjusted to get the approximate shape of the target profile.Then the adjusted feature vertexes are induced into the constructed optimization and constraint models,and the improved particle swarm optimization algorithm is used for optimization.And a new profile that meets the constraint conditions is obtained.Compared to the origin profile,the stroke volume of the new profile had increased by 3.39% and volume-reduction ratio of gas-absorbing cavity has been increased by 12.56%,which proves the feasibility and correctness of this optimization and design method. |
