布管方式对U形管式换热器管板强度的影响研究

Study of Effects of Different Tube Patterns on the Strength of Tubesheet of U-tube Heat Exchanger

以某U形管式冷凝器为例,建立了正三角形及正方形布管方式管板模型。采用有限元热-固耦合分析方式,对比研究了两种布管方式对管板热应力和机械应力的影响,并考察了管板厚度及换热管管径等参数变化的影响。研究结果表明,较正三角形布管方式,正方形布管方式能有效降低管板中由温差引起的热应力水平,但会提高由压差引起的机械应力水平;在管板的减薄与优化过程中,较正方形布管方式,正三角形布管方式管板厚度的下限值更小;管板与壳体连接处易出现应力集中现象,在换热器设计中适当增大换热管管径,有利于减小管板与壳体连接处的应力值。

By taking a U-tube condenser as an example,the models of tubesheet with triangle and square tube patterns were established.The effects of the two tube patterns on the thermal stress and mechanical stress of the tubesheet were compared and studied by finite element heat-structure coupling analysis method,and effects of the variation of the tubesheet thickness and pipe diameter were investigated.The research results show that compared with triangle tube pattern,square tube pattern can effectively reduce the thermal stress caused by temperature difference in the tubesheet,but will increase the mechanical stress caused by pressure difference.In the process of thinning and optimization of the tubesheet,compared with the square tube pattern,the minimum thickness of the tubesheet with triangle tube pattern which satisfies the strength requirement is smaller.Stress concentration is easy to occur at the connection between tubesheet and shell,and increasing the pipe diameter appropriately helps reduce the stress at the connection between tubesheet and shell in the design of heat exchanger.