Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 Issue 1 (Special Issue) 2021 03 21 Simulation of Two-Phase Flow and Heat Transfer in a Channel and around a Tube by Lattice-Boltzmann Method Simulation of Two-Phase Flow and Heat Transfer in a Channel and around a Tube by Lattice-Boltzmann Method 499 516 3709 10.22060/mej.2019.16044.6272 FA Sima Bajalan Ph.D. Student, Department of Mechanical Engineering, College of Engineering, Guilan University 0000-0002-6208-6167 Ramin Kouhi Kamali Associate Professor, Department of Mechanical Engineering, College of Engineering, Guilan University 0000-0002-8004-0242 Mohammad Hasan Rahimian Associate Professor, Department of Mechanical Engineering, College of Engineering, Tehran University Journal Article 2019 04 09 Determination of multiphase flow dynamics and thermal behavior of two-phase flow in a channel are of importance. The small-scale surface tension effect and related simulation efficiency, precision, and stability, have caused mesoscopic Lattice Boltzmann method broadening application. In the current study, the thermal-hydraulic behavior of subcooled falling flow in a vertical channel and around a single horizontal tube is simulated by using the Lee method and phase-filed model, and thermal passive scalar model. The modified curved boundary conditions and two different boundary conditions for side boundaries are investigated. The density ratio is 20 and other property’s ratios of water are applied, and the outside diameter of the tube is 28.9mm. The flow, temperature, and pressure fields are presented and a detailed understanding of the movement of the three-phase contact line, circulating flow and local and average Nusselt numbers are determined. The film thickness, thermal boundary layer variation by the film thickness, Reynold number effect on Nusselt number and mass conservation are investigated as verification. The results have shown good consistency and high effectiveness in the simulation of multiphase gas-liquid flows in the presence of a circular obstacle, and for viscosity and thermal diffusivity ratios of water. Determination of multiphase flow dynamics and thermal behavior of two-phase flow in a channel are of importance. The small-scale surface tension effect and related simulation efficiency, precision, and stability, have caused mesoscopic Lattice Boltzmann method broadening application. In the current study, the thermal-hydraulic behavior of subcooled falling flow in a vertical channel and around a single horizontal tube is simulated by using the Lee method and phase-filed model, and thermal passive scalar model. The modified curved boundary conditions and two different boundary conditions for side boundaries are investigated. The density ratio is 20 and other property’s ratios of water are applied, and the outside diameter of the tube is 28.9mm. The flow, temperature, and pressure fields are presented and a detailed understanding of the movement of the three-phase contact line, circulating flow and local and average Nusselt numbers are determined. The film thickness, thermal boundary layer variation by the film thickness, Reynold number effect on Nusselt number and mass conservation are investigated as verification. The results have shown good consistency and high effectiveness in the simulation of multiphase gas-liquid flows in the presence of a circular obstacle, and for viscosity and thermal diffusivity ratios of water. https://mej.aut.ac.ir/article_3709_56db57b4db0a6fcb7f9e0c0b504f6472.pdf