Sadaf Gul Unar¹, Shoaib Ahmed Khatri^1,*, Nayyar Hussain Mirjat¹, Muhammad Faraz Arain¹, Syed Rafay Ahmed Zaidi¹, Laveet Kumar²

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 479-505, 2025, DOI:10.32604/fhmt.2025.063937 - 25 April 2025

Abstract This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic (PV) and solar thermal systems for sustainable food preservation in Pakistan, addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources. The proposed active hybrid solar dryer features a drying cabinet, two Direct Current (DC) fans for forced convection, and a resistive heating element powered by a 180 W solar PV panel. An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance, poor weather conditions, or nighttime. Tomatoes, a delicate and in-demand crop, were… More >

Yiming Rongyang¹, Chengyu Ji¹, Xiangdong Ding^2,*, Jun Gao¹, Jianjian Wei^2,3

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 685-701, 2025, DOI:10.32604/fhmt.2025.063785 - 25 April 2025

Abstract The effect of gradient exhaust strategy and blind plate installation on the inhibition of backflow and thermal stratification in data center cabinets is systematically investigated in this study through numerical methods. The validated Re-Normalization Group (RNG) k-ε turbulence model was used to analyze airflow patterns within cabinet structures equipped with backplane air conditioning. Key findings reveal that server-generated thermal plumes induce hot air accumulation at the cabinet apex, creating a 0.8°C temperature elevation at the top server’s inlet compared to the ideal situation (23°C). Strategic increases in backplane fan exhaust airflow rates reduce server 1’s inlet… More >

Zainab Mahdi Saleh^1,*, Riyadh S. Al-Turaihi¹, Zena Khalefa Kadhim²

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 615-650, 2025, DOI:10.32604/fhmt.2025.063404 - 25 April 2025

Abstract This study involved numerical simulations of a double tube heat exchanger using the ANSYS FLUENT program version 22. The study aims to examine methods for minimizing pressure loss and consequently enhancing the thermal performance index (TPI) of a heat exchanger fitted with wavy edge tape that is a heat recovery system (the hot air in simulation instead of t heat from the exhaust gases of the brick factory furnaces and return it to warm the heavy fuel oil by substituting the electrical heater with a heat exchanger to recuperate waste heat from the flue gases,… More >

Ridha Djebali^1,*, Bernard Pateyron², Mokhtar Ferhi¹, Mohamed Ouerhani³, Karim Khemiri¹, Montassar Najari¹, M. Ammar Abbassi⁴, Chohdi Amri⁵, Ridha Ennetta⁶, Zied Driss⁷

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 441-461, 2025, DOI:10.32604/fhmt.2025.063375 - 25 April 2025

Abstract This paper investigates the application of Direct Current Atmospheric Plasma Spraying (DC-APS) as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates. The process uses a high-speed, high-temperature plasma jet to melt and propel the feedstock powder particles, making it particularly useful for improving the performance and durability of components in renewable energy systems such as solar cells, wind turbines, and fuel cells. The integration of nanostructured alumina (Al₂O₃) thin films into multilayer coatings is considered a promising advancement that improves mechanical strength, thermal stability, and environmental resistance. The More >

Hao Li¹, Cunlu Zhao², Jinhui Zhou¹, Jun Zhang³, Hui Wang¹, Yanmei Jiao^1,*, Yugang Zhao^4,5,*

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 507-528, 2025, DOI:10.32604/fhmt.2025.063359 - 25 April 2025

Abstract Based on the rapid advancements in nanomaterials and nanotechnology, the Nanofluidic Reverse Electrodialysis (NRED) has attracted significant attention as an innovative and promising energy conversion strategy for extracting sustainable and clean energy from the salinity gradient energy. However, the scarcity of research investigating the intricate multi-factor coupling effects on the energy conversion performance, especially the trade-offs between ion selectivity and mass transfer in nanochannels, of NRED poses a great challenge to achieving breakthroughs in energy conversion processes. This numerical study innovatively investigates the multi-factor coupling effect of three critical operational factors, including the nanochannel configuration,… More >

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 >

Umi Nadrah Hussein¹, Najiyah Safwa Khashi’ie^1,*, Norihan Md Arifin², Ioan Pop³

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 383-395, 2025, DOI:10.32604/fhmt.2025.063023 - 25 April 2025

Abstract This study investigates the heat transfer and flow dynamics of a ternary hybrid nanofluid comprising alumina, copper, and silica/titania nanoparticles dispersed in water. The analysis considers the effects of suction, magnetic field, and Joule heating over a permeable shrinking disk. A mathematical model is developed and converted to a system of differential equations using similarity transformation which then, solved numerically using the bvp4c solver in Matlab software. The study introduces a novel comparative analysis of alumina-copper-silica and alumina-copper-titania nanofluids, revealing distinct thermal conductivity behaviors and identifying critical suction values necessary for flow stabilization. Dual solutions… 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 >

Yumei Lv¹, Wei Dai², Shupeng Xie¹, Peng Hu^1,*, Fei He^1,*

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 397-420, 2025, DOI:10.32604/fhmt.2025.062781 - 25 April 2025

Abstract Aiming at the global design issue of transpiration cooling thermal protection system, a self-driven circulation loop is proposed as the internal coolant flow passage for the transpiration cooling structure to achieve adaptive cooling. To enhance the universality of this internal cooling pipe design and facilitate its application, numerical studies are conducted on this system with four commonly used cooling mediums as coolant. Firstly, the accuracy of the numerical method is verified through an established experimental platform. Then, transient numerical simulations are performed on the flow states of different cooling mediums in the new self-circulation system. More >

Guoguang Li, Qi Wu, Hanli Bi, Zhichao Jia, Hongxing Zhang^*, Jinyin Huang, Jianyin Miao

Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 651-662, 2025, DOI:10.32604/fhmt.2025.062191 - 25 April 2025

Abstract The loop heat pipe with a flat evaporator is mainly divided into two forms: rectangular evaporator and disk-shaped evaporator. The rectangular evaporator has advantages such as low heat leakage, a thin shell, and a large contact area compared to the disk-shaped evaporator. However, most of the research on rectangular evaporators focuses on working fluids such as water, methanol, and acetone, when these working fluids are in operation, the internal pressure of the evaporator is less than atmospheric pressure. Ammonia, propylene, and other working fluids can also be utilized in the loop heat pipe, these working… More >