Najiba Hasan Hamad^1,*, Ranj Sirwan Abdullah², Ahmed Mohammed Adham²

Energy Engineering, Vol.123, No.1, 2026, DOI:10.32604/ee.2025.073377 - 27 December 2025

Abstract Coiled tube heat exchangers are widely preferred in shell structures due to their superior heat transfer performance, driven by favorable flow characteristics. This study investigates the effect of modifying coil and shell configurations on heat transfer efficiency. Two key enhancements were examined: adding fins to the outer coil surface and integrating longitudinal slots within a hollowed shell. These modifications promote turbulence and extend heat transfer duration, thereby improving performance. However, they also introduce challenges, including increased pressure loss and manufacturing complexity. Numerical simulations were conducted using ANSYS Fluent 2024R1 under identical boundary conditions. With a… More > Graphic Abstract

Abdelhakim Lahrech¹, Tahar Tayebi², Mohamed Kallel^3,*, Mehdi Hashemi-Tilehnoee^4,*, Ali J. Chamkha⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.144, No.1, pp. 359-385, 2025, DOI:10.32604/cmes.2025.067099 - 31 July 2025

Abstract The study considers numerical findings regarding magneto-thermosolutal-aided natural convective flow of alumina/water-based nanofluid filled in a non-Darcian porous horizontal concentric annulus. Two equations are assumed to evaluate the thermal fields in the porous medium under Local Thermal Non-Equilibrium (LTNE) conditions, along with the Darcy-Brinkman-Forchheimer model for the flow. By imposing distinct and constant temperatures and concentrations on both internal and external cylinders, thermosolutal natural convection is induced in the annulus. We apply the finite volume method to solve the dimensionless governing equations numerically. The thermal conductivity and viscosity of the nanofluid mixture are determined utilizing… More >

Bo Yu^1,2, Yuye Luo³, Luyao Guo⁴, Long Huang^4,*

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 553-575, 2025, DOI:10.32604/fhmt.2025.062851 - 25 April 2025

Abstract This study investigates the flow boiling heat transfer coefficient and pressure gradient of refrigerant R410A in micro-channel flat tubes. Experiments were conducted at saturation temperatures ranging from 25°C to 30°C, mass fluxes between 198 and 305 kg/m²s, and heat fluxes from 9.77 to 20.18 kW/m², yielding 99 sets of local heat transfer coefficient data. The results show that increasing heat flux and mass flux enhances the heat transfer coefficient, although the rate of enhancement decreases with increasing vapor quality. Conversely, higher saturation temperatures slightly reduce the heat transfer coefficient. Additionally, the experimental findings reveal discrepancies in More >

Zahraa N. Hussain^1,*, Jamal M. Ali^1,*, Hasan S. Majdi², Abbas J. Sultan¹, H. Al-Naseri³

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.2, pp. 351-370, 2025, DOI:10.32604/fdmp.2024.056292 - 06 March 2025

Abstract The use of nanofluids as heat transfer media represents an innovative strategy to enhance heat transfer performances. This study investigates experimentally the turbulent convective heat transfer characteristics of water-based nanofluids containing TiO₂, CuO, and graphene nanoplatelet (GNP) nanoparticles as they flow through a copper tube. Both the dynamic viscosity and thermal conductivity of these nanofluids were modeled and experimentally measured across varying nanoparticle concentrations (0.01, 0.02, and 0.03 vol.%) and temperatures (25°C, 35°C, and 45°C). The findings indicate that the behavior of nanofluids depends on the parameter used for comparison with the base fluid. Notably, both More > Graphic Abstract

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 - 26 March 2024

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 >

Fayi Yan^*, Xuejian Pei, He Lu, Shuzhen Zong

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 287-304, 2024, DOI:10.32604/fhmt.2023.045038 - 21 March 2024

Abstract As compact and efficient heat exchange equipment, helically coiled tube-in-tube heat exchangers (HCTT heat exchangers) are widely used in many industrial processes. However, the thermal-hydraulic research of liquefied natural gas (LNG) as the working fluid in HCTT heat exchangers is rarely reported. In this paper, the characteristics of HCTT heat exchangers, in which LNG flows in the inner tube and ethylene glycol-water solution flows in the outer tube, are studied by numerical simulations. The influences of heat transfer characteristics and pressure drops of the HCTT heat transfers are studied by changing the initial flow velocity,… More >

Karema A. Hamad^*, Yasser A. Mahmood

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.11, pp. 2863-2875, 2023, DOI:10.32604/fdmp.2023.029049 - 18 September 2023

Abstract The cooling of a (pebble bed) spent fuel in a high-temperature gas-cooled reactor (HTGR) is adversely affected by an increase in the temperature of the used gas (air). To investigate this problem, a configuration consisting of three copper spheres arranged in tandem subjected to a forced mist flow inside a cylindrical channel is considered. The heat transfer coefficients and related variations as a function of Reynolds number are investigated accordingly. The experimental results show that when compared to those with only airflow, the heat transfer coefficient of the spherical elements with mist flow (j = More >

Tiezhu Sun^*, Huan Sun, Tingzheng Tang, Yongcheng Yan, Peixuan Li

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2519-2531, 2023, DOI:10.32604/fdmp.2023.027118 - 25 June 2023

Abstract The so-called indirect evaporative cooling technology is widely used in air conditioning applications. The thermal characterization of tube-type indirect evaporative coolers, however, still presents challenges which need to be addressed to make this technology more reliable and easy to implement. This experimental study deals with the performances of a tube-type indirect evaporative cooler based on an aluminum tube with a 10 mm diameter. In particular, the required tests were carried out considering a range of dry-bulb temperatures between 16°C and 18°C and a temperature difference between the wet-bulb and dry-bulb temperature of 2°C∼4°C. The integrated convective More > Graphic Abstract

Fithry Mohd Amir^*, Mohd Zamri Yusoff, Saiful Hasmady Abu Hassan

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-15, 2022, DOI:10.5098/hmt.18.27

Abstract Nanofluid film on a horizontal tube is investigated numerically on the circular and multi-faceted cylinder. The fluid flow characteristics, including film thickness, shear stress, and thermal performance, are observed and analyzed. Fluid film on the circular surface is typical in many engineering applications, but the study of nanofluid film on non-circular surface is deficient in literature. The study provides a numerical model of a multi-faceted cylinder to simulate the nanofluid film on the non-circular surfaces using a volume of fluid (VOF) method. The ratio of Brownian motion to thermophoretic diffusion, N_BT developed along the film thickness More >

Dorsaf Khalifa^*, Foued Mzali

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1841-1852, 2022, DOI:10.32604/fdmp.2022.022060 - 27 June 2022

Abstract The interfacial heat transfer coefficient (IHTC) is one of the main input parameters required by casting simulation software. It plays an important role in the accurate modeling of the solidification process. However, its value is not easily identifiable by means of experimental methods requiring temperature measurements during the solidification process itself. For these reasons, an optimal experiment design was performed in this study to determine the optimal position for the temperature measurement and the optimal thickness of the rectangular cast iron part. This parameter was identified using an inverse technique. In particular, two different algorithms… More >