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 did not have significant effects… More >

B.G. Suhas^a,* , A. Sathyabhama^b, Kavadiki Veerabhadrappa^a , R. Suresh Kumar^a, U. Kiran Kumar^a

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.16

Abstract In the present study, heat transfer coefficient of water-ethanol mixture in the subcooled boiling region is determined in a rectangular conventional channel (Channel size ≥3 mm). When the heat flux and mass flux increase it is observed that heat transfer coefficient increases. But the effect of heat flux is significant when compared with that of mass flux in the subcooled boiling region. It is found that maximum and minimum heat transfer coefficient are observed for mixture with 25% Ethanol volume fraction and 75% Ethanol volume fraction respectively. Wall heat flux partitioning analyses is carried out for mixture with different ethanol… 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 terms of flow and heat… More >

Rabha Khatyr^*, Jaafar Khalid Naciri

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-11, 2020, DOI:10.5098/hmt.15.5

Abstract The present study focuses on the effects of viscous dissipation and axial heat conduction on the asymptotic behavior of the laminar forced convection in a circular duct for a Herschel-Bulkley fluid with variable wall heat flux. Analytical asymptotic solutions are presented for the case of axial variations of the wall heat flux, with finite non-vanishing values at infinity along the flow direction. The asymptotic bulk and mixing Nusselt numbers and the asymptotic bulk and mixing temperature distributions are evaluated analytically in the case of axially variable wall heat flux for which polynomial and logarithmic functions are considered as examples. It… More >

Rabha Khatyr^*, Jaafar Khalid Naciri

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-8, 2022, DOI:10.5098/hmt.19.23

Abstract The aim is to study the asymptotic behavior of the temperature field for the laminar forced convection of a Herschel-Bulkley fluid flowing in a circular duct considering both viscous dissipation and axial heat conduction. The asymptotic bulk and mixing Nusselt numbers and the asymptotic bulk and mixing temperature distribution are evaluated analytically in the cases of uniform wall temperature and convection with an external isothermal fluid. In particular, it has been proved that the fully developed value of Nusselt number for convective boundary conditions is independent of the Biot number and is equal to the value of fully developed Nusselt… More >

Farhan Lafta Rashid^a , Abbas Fadhil Khalaf^a, Ahmed Kadhim Hussein^b, Mohamed Bechir Ben Hamida ^c,d,e, Bagh Ali^f, Obai Younis^g,*

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-6, 2022, DOI:10.5098/hmt.19.21

Abstract Convection and conduction in a fluid flow and a rigid body in contact with each other often occur in engineering situations, resulting in unsteady conjugate heat transfer (CHT). Although the analytical solutions to the separate conduction and convection issues are surprisingly straightforward, the combined conjugate heat transfer problem is substantially more complex to solve. This study investigates the CHT of a fluid (air) passing through an unbounded hemisphere. The hemisphere produces heat at a predictable and regular pace. The governing equations are solved using a finite volume system (FVS) using ANSYS Fluent V.16.0, with axisymmetric, no normal convection, and stable… More >

Wadhah Hussein Al doori^*

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-9, 2022, DOI:10.5098/hmt.19.8

Abstract Perforated fin forced convection heat transfer is the primary focus of this investigation. The purpose of this research is to see if perforated pin fins can help with heat transmission in the devices. Each pin's perforation diameter and number of holes are rigorously examined. The Nusselt numbers for perforated pins are 47 percent higher than those for solid pins, according to the study, and this number raises as the number of holes increases. The pressure drop is reduced by 19% when perforated pins are used instead of solid pins. Heat transmission in a round-holed pin fin was studied using forced… More >

Farhan Lafta Rashid^a, Sarmad Kamal Fakhrulddin^b, Muhammad Asmail Eleiwi^c, Ahmed Kadhim Hussein^d,e, Tahseen Ahmad Tahseen^f , ObaiYounis^g,h,*, Mohammed Ibrahim Ahmedⁱ

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-8, 2022, DOI:10.5098/hmt.19.6

Abstract The current study numerically analyzes the heat transfer enhancement and laminar fluid flow characteristics of four flat tubes with varying attack front airflow. The heat transfer characteristics of flat tubes are investigated in terms of Reynolds number, heat fluxes, and inclination angle. Four Reynolds numbers are studied (100, 200, 300, and 400), and three heat fluxes on the surface of the tubes are (1000, 2500, 3800 W/m2 ), the inclination angle of the four flat tubes are (30o , 45o , 90o). ANSYS Fluent software v.18 discretizes and solves the governing equations using the finite volume approach across a specified… More >

Cong Qi^1,2,*, Chengchao Wang^1,2, Jinghua Tang^1,2, Dongtai Han²

Energy Engineering, Vol.117, No.2, pp. 63-78, 2020, DOI:10.32604/EE.2020.010433

Abstract Because of the poor thermal performance of ordinary tubes, a triangular tube was used to replace the smooth channel in the heat transfer system, and nanofluids were used to take the place of ordinary fluids as the heat transfer medium. High stability nanofluids were prepared, and an experimental set on flow and heat exchange was established. Effects of triangular tube rotation angles (α = 0°, 30°, 60°) as well as mass fractions of nanofluids (ω = 0.1%, 0.3%, 0.5%) on heat exchange and flow performance were experimentally considered at Reynolds numbers (Re = 800–8000). It was shown that the triangular… More >

Kai-Long Hsiao¹, Cheng-Hsing Hsu²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.1, pp. 3-22, 2009, DOI:10.3970/icces.2009.009.003

Abstract A conjugate forced convection with viscous dissipation heat transfer problem of a second-grade visco-elastic fluid past a flat plate fin has been studied. Governing equations include heat conduction equation of the fin, and continuity equation, momentum equation and energy equation of the fluid, were analyzed by a combination of a series expansion method, the similarity transformation and a second-order accurate finite-difference method. Solutions of a stagnation flow (β = 1.0) at the fin tip and a flat plate shape (wedge flow β = 0.0) on the fin surface were obtained by a generalized Falkner-Skan flow derivation. These solutions were used… More >