Kun Yan¹, Yunyu Wang², Jun Yan^3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.2, pp. 1949-1974, 2024, DOI:10.32604/cmes.2024.048877

Abstract Topology optimization of thermal-fluid coupling problems has received widespread attention. This article proposes a novel topology optimization method for laminar two-fluid heat exchanger design. The proposed method utilizes an artificial density field to create two permeability interpolation functions that exhibit opposing trends, ensuring separation between the two fluid domains. Additionally, a Gaussian function is employed to construct an interpolation function for the thermal conductivity coefficient. Furthermore, a computational program has been developed on the OpenFOAM platform for the topology optimization of two-fluid heat exchangers. This program leverages parallel computing, significantly reducing the time required for More >

Yang Cao^1,*, Jianshu Liu², Xuhui Meng¹

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 675-685, 2024, DOI:10.32604/fhmt.2024.051208

Abstract Boiling heat transfer, as an efficient heat transfer approach, that can absorb a large amount of latent heat during the vaporization, is especially suitable for heat transfer occasions with high heat flux demands. Experimental studies show that the surface tension coefficient of pure water can be reduced sharply (up to 25%) when it is magnetized by a magnetic field applied externally. In this paper, magnetized water (MW) was used as the work fluid to conduct boiling heat transfer experiments, to explore the influence of magnetization on the boiling characteristics of pure water. The electromagnetic device… More >

Mohammad Yaghoub Abdollahzadeh Jamalabadi^*

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 511-536, 2024, DOI:10.32604/fhmt.2024.051004

Abstract Heat and mass transport through evaporation or drying processes occur in many applications such as food processing, pharmaceutical products, solar-driven vapor generation, textile design, and electronic cigarettes. In this paper, the transport of water from a fresh potato considered as a wet porous media with laminar convective dry air fluid flow governed by Darcy’s law in two-dimensional is highlighted. Governing equations of mass conservation, momentum conservation, multiphase fluid flow in porous media, heat transfer, and transport of participating fluids and gases through evaporation from liquid to gaseous phase are solved simultaneously. In this model, the… More >

P. Pai Nityanand, B. Devaki, G. Bhat Pareekshith, V. S. Sampath Kumar^*

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 655-673, 2024, DOI:10.32604/fhmt.2024.050237

Abstract The study in this manuscript aims to analyse the impact of thermal radiation on the two-dimensional magnetohydrodynamic flow of upper convected Maxwell (UCM) fluid between parallel plates. The lower plate is porous and stationary, while the top plate is impermeable and moving. The equations that describe the flow are transformed into non-linear ordinary differential equations with boundary conditions by employing similarity transformations. The Homotopy Perturbation Method (HPM) is then employed to approach the obtained non-linear ordinary differential equations and get an approximate analytical solution. The analysis includes plotting the velocity profile for different Reynolds number… More >

Ali Shokor Golam^*

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 633-653, 2024, DOI:10.32604/fhmt.2024.050218

Abstract The thermal-hydraulic performance of plain tubes with and without wire coils in turbulent regimes is investigated experimentally and numerically. The effects of wire coil distribution (circular cross section) within the tube were explored experimentally, and water was employed as the working fluid. The numerical simulation was carried out using software programmer ANSYS Fluent 2019 R3 using the finite-volume approach. In the turbulent regime, six cross-sectioned wire coils were analyzed, including: circular, rectangular, hexagonal, square, star shape, and triangle. The utilization of a tube with a wire coil has been shown to increase heat transfer rate More >

Yang Cao^*, Xuhui Meng

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 583-595, 2024, DOI:10.32604/fhmt.2024.049111

Abstract In this paper, a new approach called the Eulerian species method was proposed for simulating the convective and/or boiling heat transfer of nanofluids. The movement of nanoparticles in nanofluids is tracked by the species transport equation, and the boiling process of nanofluids is computed by the Eulerian multiphase method coupled with the RPI boiling model. The validity of the species transport equation for simulating nanoparticles movement was verified by conducting a simulation of nanofluids convective heat transfer. Simulation results of boiling heat transfer of nanofluids were obtained by using the commercial CFD software ANSYS Fluent More >

Ming Yan¹, Caijiang Lu^2,*, Pan Shi^1,*, Meiling Zhang³, Jiawei Zhang¹, Liang Wang¹

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 615-631, 2024, DOI:10.32604/fhmt.2024.048333

Abstract In response to escalating challenges in energy conservation and emission reduction, this study delves into the complexities of heat transfer in two-phase flows and adjustments to combustion processes within coal-fired boilers. Utilizing a fusion of hybrid modeling and automation technologies, we develop soft measurement models for key combustion parameters, such as the net calorific value of coal, flue gas oxygen content, and fly ash carbon content, within the Distributed Control System (DCS). Validated with performance test data, these models exhibit controlled root mean square error (RMSE) and maximum absolute error (MAXE) values, both within the… More > Graphic Abstract

Ghobad Shafiei Sabet^1,*, Ali Sari¹, Ahmad Fakhari^2,*, Nasrin Afsarimanesh³, Dominic Organ⁴, Seyed Mehran Hoseini¹

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 491-509, 2024, DOI:10.32604/fhmt.2024.048290

Abstract This study conducts both numerical and empirical assessments of thermal transfer and fluid flow characteristics in a Solar Air Collector (SAC) using a Delta Wing Vortex Generator (DWVG), and the effects of different height ratios (R = 0.6, 0.8, 1, 1.2 and 1.4) in delta wing vortex generators, which were not considered in the earlier studies, are investigated. Energy and exergy analyses are performed to gain maximum efficiency. The Reynolds number based on the outlet velocity and hydraulic diameter falls between 4400 and 22000, corresponding to the volume flow rate of 5.21–26.07 m/h. It is More >

Ritesh Singh¹, Abhishek Gupta¹, Akshoy Ranjan Paul¹, Bireswar Paul¹, Suvash C. Saha^2,*

Energy Engineering, Vol.121, No.4, pp. 835-848, 2024, DOI:10.32604/ee.2024.046849

Abstract A parabolic trough solar collector (PTSC) converts solar radiation into thermal energy. However, low thermal efficiency of PTSC poses a hindrance to the deployment of solar thermal power plants. Thermal performance of PTSC is enhanced in this study by incorporating magnetic nanoparticles into the working fluid. The circular receiver pipe, with dimensions of 66 mm diameter, 2 mm thickness, and 24 m length, is exposed to uniform temperature and velocity conditions. The working fluid, Therminol-66, is supplemented with Fe₃O₄ magnetic nanoparticles at concentrations ranging from 1% to 4%. The findings demonstrate that the inclusion of nanoparticles… More >

Alexander A. Fedorets¹, Eduard E. Kolmakov¹, Leonid A. Dombrovsky^1,2,3,*

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 1-14, 2024, DOI:10.32604/fhmt.2024.049335

Abstract New experimental results, which are important for the potential use of small levitating droplets as biochemical microreactors, are reported. It is shown that the combination of infrared heating and reduced evaporation of saline water under the droplet cluster is sufficient to produce equilibrium saltwater droplets over a wide temperature range. The resulting universal dependence of droplet size on temperature simplifies the choice of optimal conditions for generating stable droplet clusters with droplets of the desired size. A physical analysis of the experimental results on the equilibrium size of saltwater droplets makes it possible to separate More > Graphic Abstract