基于叶片角变化规律的液力变矩器改型设计法

Design Strategy for Modification of Torque Converters Based on Variation Law of Blade Angle

摘要:

研究了三维设计环境下液力变矩器叶栅系统改型设计方法,提出以叶片角变化规律为基础对原型叶片进行改型设计.首先,通过初始化图形交换规范(IGES)与三维软件交换叶栅系统的三维信息;然后,利用De Boor算法的开花计算叶片上各点处的叶片角,将反映叶片角沿叶片内外环设计基线变化的曲线拟合成非均匀有理B样条(NURBS),通过调整NURBS曲线的控制点以及各控制点权重值,实现叶片角变化规律的调整;确定了新的叶片角变化规律后,叶片的空间形状即可确定,从而可以生成新的叶栅系统模型;最后,对新生成的叶栅系统进行性能预测,得到满意的结果后即可进入后续详细设计阶段.利用该方法构建了液力变矩器改型平台,使用该平台分别以提高变矩性能和提高效率为目标对某款液力变矩器进行改型研究,结果表明所提出的方法行之有效,有助于提高改型设计的效率.

Abstract:

A design strategy is presented for modification of torque converters based on variation law of blade angle along design path.First,the initial graphics exchange specification (IGES) format is utilized as an interface to exchange cascade system data with computer aid design (CAD) software.Then,blade angle is calculated by using the blossoming of De Boor algorithm.The design paths which indicate variation law of blade angle are fitted to strings of nonuniform rational Bspline (NURBS).After that,it is possible to modify the design paths of blade angle by relocalizing control points or modifying weight values of them.Once the modified design paths of blade angle are obtained,blade shape is redefined.Afterwards,the modified torque converter model is transmitted to computational fluid dynamics (CFD) package for hydraulic performance prediction.The modification iterations might be carried on for several times before a desired performance is achieved.Finally,the modified torque converter model can be transmitted to CAD software for further detailed design.A modification design which’s to improve torque converting performance and economic performance respectively for one certain torque converter product is carried out based on the presented design strategy.The result shows that the proposed framework provides reasonable results and proves to be time efficiency.