| Hydraulic retarder is mainly composed of working chamber,cooling system,air intake system and electronic control device,its working by hydraulic braking converts the kinetic energy of vehicle into the heat energy of oil.Hydraulic retarder is widely used in the construction machinery braking system,because of its long service life,high braking torque characteristic,also improving the standard of driving safety when long time braking,providing more comfortable driving experience and environmental protection.The research on the interior flow of hydraulic retarder is not deep enough in the domestic,especially lack of research on improving braking efficiency and reducing the pumping losses.Therefore,this article discusses the mentioned above and puts forward a new curved blade design of hydraulic efficiency,aiming to solve the problem of braking efficiency and pumping losses.Based on the cascade system and optimization modeling,an integrated design system with high flexibility and adaptability has been established,which has great significance to improve the performance of hydraulic,ultimately,the braking torque is improved and pumping loss is reduced.The main research work of this paper are as follows:(1)Based on the geometric characteristics of blades of hydraulic retarder,circulatory circle model of hydraulic retarder is established,combined with flow loss analysis of straight blade with two theories of control flow and back-loaded blade,a blade shape design of bent back-loaded for hydraulic retarder is proposed.(2)The design of curved back-loaded blade is based on the Bezier curve to build the back curve of blade,and it is combined with both three Bessel curves of ascending and descending segments,the ventral curve of blade is built by geometric model,the optimization of the whole blade design is improved,and the parametric design model of hydraulic retarder based on the cascade system is established.(3)The optimization design of cascade system as the core of CFD analysis contains geometry modeling,meshing and flow field calculation.Based on the 3D flow field simulation technology,consider the design variables of blade angle and circle radius as the optimization parameters,combined with multi island genetic algorithm(MIGA),and then the optimal solution is received.(4)Under the use of optimization cascade design system,combined with numericalsimulation of the flow field in the method of back-loaded blade optimization design,the inner cycle energy flow and braking characteristics of hydraulic retarder are analyzed before and after optimization,compared with before and after analysis,the optimization scheme has a certain degree of improvement on the braking torque coefficient and the braking torque on different speed,the inner flow losses have been significantly reduced,and the braking performance are significantly improved. |
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