Dongxiao Zhang¹, Lin Lu^1,*, Xiaobin Qi^2,3, Xuepu Yan¹, Cisong Gao¹, Yanxiao Hu¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2707-2728, 2023, DOI:10.32604/fdmp.2023.028641

Abstract A two-dimensional model, employing a dynamic mesh technology, is used to simulate numerically the transient multiphase flow field produced by two submerged parallel guns. After a grid refinement study ensuring grid independence, five different conditions are considered to assess the evolution of cavitation occurring in proximity to the gun muzzle. The simulation results show that flow interference is enabled when the distance between the parallel barrels is relatively small; accordingly, the generation and evolution of the vapor cavity becomes more complex. By means of the Q criterion for vorticity detection, it is shown that cavitation More >

Rahouadja Zarita^*, Madjid Hachemi

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-12, 2019, DOI:10.5098/hmt.12.5

Abstract In this work, heat transfer enhancement in a microchannel using water-Ag nanofluid has been investigated numerically by the lattice Boltzmann method (LBM) by adopting the stream and collide algorithm, with the (BGK) approximation. The base fluid and the suspended nanoparticles are considered as a homogeneous mixture. And single phase model with first order slip and jump boundary conditions has been adopted. Thermophysical properties of water-Ag nanofluid are estimated by the theoretical models. Effects of change in nanoparticle volume fractions, Reynolds number and Knudsen number are considered. It was concluded that change in nanoparticle volume fractions More >

Hasan Sh. Majdi^a , Ammar Abdulkadhim^b,* , Azher M. Abed^b

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-14, 2019, DOI:10.5098/hmt.12.2

Abstract Fluid flow and natural convection heat transfer in a parallelogram enclosure with an inner circular cylinder using Cu-water nanofluid are studied numerically. Dimensionless Navier-Stokes and energy equations are solved numerically using finite element method based two-dimensional flow and steady-state conditions. This study evaluates the effect of different concentrations of Cu-water nanofluids (0% to 6%) with different Rayleigh numbers 10³ ≤ Ra ≤ 10⁶ under isotherm wall temperatures. The effects of geometrical parameters of the parallelogram enclosure (inclination angle in range of 0 ≤ α ≤ 30 and location of inner circular cylinder -0.2 ≤ H ≤… More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.14, pp. 1-11, 2020, DOI:10.5098/hmt.14.27

Abstract Numerical predictions on heat transfer characteristic, flow topology and thermal performance assessment in a square duct are presented. The passive technique, insertion of the vortex generator, is opted to develop the heat transfer rate in the square duct heat exchanger. The vortex generator of the present research is Double V-Orifice (DVO). The square duct equipped with DVO is tested with various parameters. The influences of DVO height, b, to the duct height, H, or b/H, gap spacing between the outer edge of the orifice and the duct wall, s, to the duct height or s/H… More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-15, 2020, DOI:10.5098/hmt.15.13

Abstract Simulated examinations on convective heat transfer and flow topology in a square duct heat exchanger placed with wavy thin rib (WTR) are presented. The influences of WTR heights, pitch distances and flow directions on flow and heat transfer characteristics are investigated for the laminar flow regime at the inlet condition (Re = 100 – 2000). The finite volume method (SIMPLE algorithm) is picked to analyze the numerical problem. The numerical validations; grid independence and verification of the smooth duct, are presented. The simulated results of the heat exchanger duct placed with WTR are reported in More >

Pengda Li, Chao Xu, Zhirong Liao^* , Xing Ju, Feng Ye

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-10, 2020, DOI:10.5098/hmt.15.10

Abstract This study numerically investigates the charging and discharging processes of a three-stages cascaded latent heat thermal energy storage unit using three molten salts as the phase change materials (PCMs). Each stage of the unit is a vertical shell-and-tube heat exchanger, whose shell side is filled with the PCM and air. The liquid fractions, temperatures, and accumulated thermal energy of the PCMs during the fully charging and discharging processes, as well as the effects of the HTF inlet temperature, are analyzed. The results show that lower melting temperature of the PCM causes faster charging rate and More >

Kafel Azeez Mohammed^a,*, Ahmed Mustaffa Saleem^b , Zain alabdeen H. Obaid^a

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-8, 2021, DOI:10.5098/hmt.16.20

Abstract Numerical investigation is performed for the determination of Nusselt number of ZnO, TiO₂ and SiO₂ nanoparticles dispersed in 60% ethylene glycol and 40% water inside inclined cylinder for adiabatic and isothermal process. The present study was conducted for both the constant heat flux (10,000 W/m²) and constant wall temperature (313.15 K) boundary conditions. At the inlet, the uniform axial velocity and initial temperature (293 K) were assumed. The results show the change of average Nusselt number at Reynolds number (400), Rayleigh number (10⁶) and volume fraction percentage (2%). From results for adiabatic process when increasing the slop More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-16, 2021, DOI:10.5098/hmt.16.17

Abstract This research reports numerical examinations on fluid flow, heat transfer behavior and thermal performance analysis in a circular tube equipped with modified V-baffles (CTMVB). The modified V-baffle (MVB) is a combination vortex generator between V-baffles/V-orifices which are placed on the tube wall and V-baffles which are inserted at the core of the tested tube. The MVB height is separated into two parts; b1 represents the MVB height on the tube wall, while b2 represents the MVB height at the core of the tested round tube. The MVB height to tube diameter ratios, b/D, are adjusted; b₁/D… More >

Jingquan Zhang^a,b, Kun Zhang^a,b,*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-6, 2021, DOI:10.5098/hmt.17.14

Abstract Detailed numerical analysis is presented for flow and heat transfer in sinusoidal-corrugated parallel channel with six discrete heat sources placed under the bottom surface. Three dimensional numerical model are applied for simulating the flow and heat transfer process and the Colburn j factor is applied to evaluate the overall performance of the corrugated liquid cooled channel. The results show that the maximum temperature in the middle section decreases and the pressure loss increases as the wavelength of sinusoidal surface on the bottom decreases, while the increasing wave amplitude of corrugated surface can enhance the heat More >

Mei Su^a , Ligai Kang^b, Kangjie Sun^b,*

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-5, 2022, DOI:10.5098/hmt.18.22

Abstract To study the heat transfer effect of rough surface in laminar flow, the direction splitting method is introduced by fully developed fields for solving the Navier–Stokes equations of incompressible flow in assuming two-dimension. Firstly, the algorithm of the incompressible Navier–Stokes equations with pressure correct is carried out. Secondly, the effects of pressure drop and heat transfer are investigated in different rough surface elements which are configured with triangular and rectangular elements. The Reynolds number, roughness element spacing, and roughness height are also considered as the factors which affect the heat transfer. The results indicate that More >