关键词: 参数研究, 分析设计, 极限压力, 应力集中, 有限元法

Abstract: To investigate the strength design of the plate-fin heat exchanger header with lateral nozzle, the calculation procedure of limit load for plastic work curvature (PWC ) criterion by using ANSYS and Solidworks is presented, the limit pressure results of the header with 30 degree-lateral are compared for three limit pressure criteria, which are the PWC criterion, the twice elastic slope (TES) criterion and the American Society of Mechanical Engineers (ASME) limit load criterion of perfect plastic material, and the three dimensional parameters affecting the limit pressure, which are the lateral oblique angle β, the ratio of header diameter/header thickness iDδ, and the opening ratio idD, are studied. The comparison of limit pressure results for the header with 30 degree-lateral shows that the PWC limit pressure is characterized by reflecting the structural strengthening effect of the material strain-hardening on the header by using the plastic work and the plastic work curvature as the global indicators of plastic collapse mechanism, which is objective other than the arbitrary deformation parameter and the twice elastic slope failure line of TES criterion; the relationship study of limit pressure and the three dimensional parameters shows that the limit pressure is decreased with the smaller lateral oblique angle, larger opening ratio and larger header diameter/header thickness ratio. The research results can provide beneficial guideline for calculating the plastic limit pressure and selecting geometrical dimensional parameters in designing the plate-fin heat exchanger with lateral nozzle.

Key words: Design by analysis, Finite element method, Limit pressure, Parametric survey, Stress concentration