Development and validation of numerical model of condensation heat transfer and frictional pressure drop in a circular tube

• Published in: Applied thermal engineering 2018-10, Vol.143, p.225-235
• Main Authors: Qiu, Guodong, Wei, Xinghua, Cai, Weihua, Jiang, Yiqiang
• Format: Article
• Language: English
• Subjects: Accuracy; Circular tubes; Computational fluid dynamics; Computer simulation; Condensation; Condensation heat transfer; Damping; Entrainment; Finite element method; Fluid flow; Fluxes; Friction; Frictional pressure drop (FPD); Heat transfer; Heat transfer coefficient (HTC); Heat transfer coefficients; Mathematical models; Numerical analysis; Numerical model; Phase transitions; Prandtl number; Pressure drop; Reynolds stress; Turbulence; Void fraction
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2018.07.085

•Numerical model of condensation flow and heat transfer was developed and validated.•Mesh scheme has vital effect on capturing the condensation liquid film.•When entrainment is obvious, it can’t be ignored in the simulation.•Prt = 0.85 in very thin liquid film near the wall is inapplicable.•Turbulence damping was used to modify the velocity gradient at the interface. A numerical model of condensation heat transfer and frictional pressure drop in a circular tube was developed and validated. In order to facilitate the model validation, the physical model was built according to the experiment condition in the existing literature. In the numerical models proposed in this work, the following models were involved: volume of fluid (VOF) multiphase model, Lee’s phase change model and Reynolds Stress turbulence model. The importance of boundary-layer mesh size was analyzed, and the effects of entrainment, turbulent Prandtl number and gas-liquid interface turbulence damping on the simulation results of heat transfer coefficient (HTC) and frictional pressure drop (FPD) were evaluated and modified. The numerical model was validated with Neeraas’s experimental data and Steiner's correlation results at various mass fluxes, vapor qualities, pressures and fluids. The simulation results of void fraction showed good agreement with Steiner's correlation; the HTC and FPD showed good agreement with Neeraas’s experimental data, which indicated the model developed in this work has good universality and accuracy.