换热器壳侧紊流流动特性的数值研究

Numerical Study of Turbulent Flow Characteristics in Shell Side of Shell-and-Tube Heat Exchangers

根据体积多孔度、表面渗透度的概念 ,采用分布阻力方法建立了换热器壳侧紊流流动的三维数值模型 ,用修正的 κ- ε模型考虑管束对紊流的产生和耗散的影响 ,用壁面函数法处理壳壁和折流板的壁面效应 .对一管壳式换热器模型的壳侧流动特性进行了数值模拟 ,计算的压力分布与试验值进行了对比 ,并研究了不同紊流模型对计算结果的影响 .结果表明 ,计算的压力分布和试验值吻合良好 ,该模型能有效地模拟管壳式换热器壳侧流动特性 .

A three dimensional numerical model was presented for the analysis of turbulent fluid flow in shell side of shell and tube heat exchanges. The numerical model uses the distributed resistance method along with the concept of volumetric porosities, surface permeabilities to account for the presence of tubes and flow baffles in the heat exchanger. A modified κ ε model was used to account for the effects of tubes on turbulence generation and dissipation. Shell and baffle walls were modeled using the wall function approach. The volume average conservation equations of shell side fluid were solved in primitive variable form using a semi implicit consistent control volume formulation in which a segregated pressure correction linked algorithm is employed. The three dimensional model was validated by comparison of the computed pressure drop distribution with the experimental data obtained on an E shell type heat exchanger model. The effect of the turbulence model was studied. Good agreement between the simulation results and experimental ones was obtained. It shows that applying the three dimensional numerical model with the modified κ ε model can effectively simulate the turbulent fluid flow in shell and type heat exchangers.