Sajjad Tariq A. Shafi, Mohammed K. Al-Saadi, Ameer Abed Jaddoa^*

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 703-719, 2025, DOI:10.32604/fhmt.2025.063118 - 25 April 2025

Abstract To improve the heat transfer rate and thermal performance of the solar air heater due to low efficiency, new techniques, such as artificial roughness, barriers, and obstacles, should be used to increase the heat exchange between the fluid and the absorber. In this research, perforated V-shaped blockages with new geometric shapes, which are circular, hexagonal, square, rectangular, and triangular, were used. They were fixed on the absorber plate inside the channel with dimensions of 1.5 m × 0.5 m × 0.05 m, which increased the exit temperature of the air passing through the channel. The… More > Graphic Abstract

L. S. Sundar^*, Sérgio M. O. Tavares, António M. B. Pereira, Antonio C. M. Sousa

Frontiers in Heat and Mass Transfer, Vol.23, No.1, pp. 131-162, 2025, DOI:10.32604/fhmt.2025.055854 - 26 February 2025

Abstract The experimental analysis takes too much time-consuming process and requires considerable effort, while, the Artificial Neural Network (ANN) algorithms are simple, affordable, and fast, and they allow us to make a relevant analysis in establishing an appropriate relationship between the input and output parameters. This paper deals with the use of back-propagation ANN algorithms for the experimental data of heat transfer coefficient, Nusselt number, and friction factor of water-based Fe₃O₄-TiO₂ magnetic hybrid nanofluids in a mini heat sink under magnetic fields. The data considered for the ANN network is at different Reynolds numbers (239 to 1874),… More >

Ali Shokor Golam^*

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 633-653, 2024, DOI:10.32604/fhmt.2024.050218 - 20 May 2024

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 >

Mainak Bhaumik¹, Anirban Sur^2,*, Kavita Dhanawade³

Frontiers in Heat and Mass Transfer, Vol.21, pp. 467-486, 2023, DOI:10.32604/fhmt.2023.044605 - 30 November 2023

Abstract Pin fins are widely used in applications where effective heat transfer is crucial. Their compact design, high surface area, and efficient heat transfer characteristics make them a practical choice for many thermal management applications. But for a high heat transfer rate and lightweight application, aerofoil shape pin fins are a good option. This work focuses on an experimental model analysis of pin-fins with aerofoil shapes. The results were evaluated between perforation, no perforation, inline, and staggered fin configurations. Aluminum is used to make the pin fins array. The experiment is carried out inside a wind… More >

O. M. Oyewola^a,b,* , M. O. Petinrin^a , and H. O. Sanusi^a

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-8, 2023, DOI:10.5098/hmt.20.16

Abstract The flow and heat transfer behaviour of channels with dimples and protrusions of spherical and piriform shapes was numerically explored by solving the Navier-Stokes and energy equations with a CFD software, the ANSYS Fluent 19.3, in the range of Reynolds numbers from 8,500 to 59,000. The values of the Nusselt number and friction factors were estimated and the non-dimensional Performance Evaluation Criterion (PEC) was determined to measure the thermal-hydraulic performance. The results reveal that the piriform protruded channel demonstrated a higher thermal performance with Nusselt number values of 36%, 15%, 23%, and 9% than the… More >

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 711-722, 2023, DOI:10.32604/fdmp.2022.021651 - 29 September 2022

Abstract The thermo-hydraulic properties of circular tubes with a twisted tape inside (used accordingly to induce turbulence and enhance heat transfer through the tube wall) are described for Reynolds Numbers ranging from 830 to 1990. Tapes twisted with the three distinct twist ratios are considered, namely, 6, 4.4 and 3. Air is used as the working fluid in several tests. For the sake of comparison, the standard tube with no insert is also examined. It is shown that in the presence of the twisted tape, the ‘frictional factor’, ‘Nusselt Number’ and the ‘thermal performance factor’ are More >

Shrikant Arunrao Thote^*, Netra Pal Singh

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 501-511, 2023, DOI:10.32604/fdmp.2022.021502 - 29 August 2022

Abstract The thermal behavior of pipes with a twisted tape inside (used to enhance heat transfer through the tube wall) is studied in the laminar flow regime. Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–2000. It is found that in such conditions the ‘Nusselt Number’ (Nu) gradually increases with reducing the tape twist ratio, whereas the friction factor is detrimentally affected by the presence of the tape (as witnessed by the comparison with the companion case where a plain tube is considered). In particular, it is shown that More >

Firas Aziz Ali^a,*, Adnan M. Alsaffawi^b , Karam Hashim Mohammed^a

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-7, 2020, DOI:10.5098/hmt.15.21

Abstract The augmentation of the heat transfer in heat exchangers is one of the methods to increase efficiency of the system. The double tube heat exchanger is selected to many suitable techniques of heat transfer enhancement. In this study; the friction factor and heat transfer coefficient of double tube is evaluated experimentally. The Al₂O₃ nanoparticles dispersed in ethylene glycol (EG) with a diameter 50 nm and the weight concentration (0.1%, 0.3%, 0.5%, 0.7%, 1%) has been utilized. Then the effect of parallel current and counter current with different ranges of Reynolds number (10,000 to 30,000) on the… More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-19, 2018, DOI:10.5098/hmt.10.6

Abstract Convective heat transfer, pressure loss and thermal performance in a heat exchanger tube inserted with the modified V-shaped baffle are investigated numerically. The influences of the flow attack angle (α = 20o , 30o and 45o ), baffle height in term of blockage ratio (b/D = BR = 0.05, 0.10, 0.15, 0.20 and 0.25) and arrangement (The V-tip pointing downstream is called “V-Downstream”, while the V-tip pointing upstream is named “V-Upstream”.) on heat transfer and friction loss are presented for the Reynolds number in range 100 – 1200 (laminar region). The numerical study (finite volume… More >

Yashwant Singh^a , Rajesh Maithani^b , Sunil Kumar^a , Ehsan Gholamalizadeh^c , Anil Kumar^a,d,*

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-16, 2018, DOI:10.5098/hmt.11.33

Abstract Nanofluids play important roles in the heat transfer and flow characteristics in ribbed square channels. Systematic experiments are conducted to measure heat transfer enhancement and TiO₂-H₂O based nanofluid flow characteristics on a protruded with combined V-type ribbed square channel. Reynolds number studied in the channel range from 4000-18000. Investigational parameters of square channel contain, volume fraction range of 1.0- 4.0%, particle diameter range of 30nm-45nm, relative protruded rib height range of 0.10-0.25, ratio of protruded height to print diameter range of 0.8- 2.0, relative protruded rib pitch ratio range of 2.0-3.5 and angle of attack of… More >