Heat and Mass Transfer in Engineering

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.9	6.1	2011	15 Days	CHF 2400	Submit
Energies energies	3.9	8.3	2008	16.7 Days	CHF 2600	Submit
Fluids fluids	2.1	4.1	2016	17 Days	CHF 1800	Submit
Mathematics mathematics	2.3	5.4	2013	17.4 Days	CHF 2600	Submit
Processes processes	3.4	5.7	2013	14.7 Days	CHF 2400	Submit

22 pages, 12861 KB

Open AccessArticle

Experimental and Numerical Investigation on Critical Heat Flux and Cooling Efficiency of Liquid Nitrogen Spray Cooling

by Yixiao Ruan, Xiaochen Zhang, Yun Zhang, He Zhang, Rong Xue and Yu Hou

Processes 2026, 14(16), 2580; https://doi.org/10.3390/pr14162580 - 13 Aug 2026

Viewed by 446

With continuously growing heat loads of microelectronic and aerospace equipment, spray cooling stands out as an effective high-heat-flux thermal management technology. Though room-temperature spray cooling has been extensively explored, liquid nitrogen spray cooling, a competitive cryogenic cooling approach, still lacks clear parametric laws [...] Read more.

With continuously growing heat loads of microelectronic and aerospace equipment, spray cooling stands out as an effective high-heat-flux thermal management technology. Though room-temperature spray cooling has been extensively explored, liquid nitrogen spray cooling, a competitive cryogenic cooling approach, still lacks clear parametric laws and heat transfer limits due to harsh and unstable low-temperature test conditions. In this paper, experiments are carried out on a semi-closed liquid nitrogen spray cooling test rig to investigate how spray flow rate, chamber pressure and spray height affect the critical heat flux (CHF) and cooling efficiency of heated surfaces. Experimental results reveal that the maximum CHF reaches 284 W·cm⁻². Increasing flow rate raises the heat transfer limit but cuts cooling efficiency, while both CHF and efficiency are barely sensitive to chamber pressure. The spray height enabling full wall coverage is optimal, delivering a peak cooling efficiency of 32.9%. The simulation explains the relationship between liquid film evolution and CHF/cooling efficiency. Simulations demonstrate that liquid film thickness rises first and then decreases moderately with growing spray height, inconsistent with the conventional view that thinner films yield superior heat transfer. The findings provide useful guidance for the design and optimization of cryogenic spray cooling systems. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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19 pages, 2398 KB

Open AccessReview

Mathematical Modeling of Heat Transfer During the Retrieval of a Downhole Sampler from an Ice Borehole: The Case of Borehole 5G-5, Vostok Station

by Sergey Ignatiev, Mikhail Kuznetsov and Andrey Dmitriev

Energies 2026, 19(10), 2345; https://doi.org/10.3390/en19102345 - 13 May 2026

Viewed by 524

Abstract

During the drilling of deep ice boreholes in Central Antarctica, one of the key tasks is to collect representative samples of the borehole fluid. The principal challenge is that, during retrieval of the downhole sampler to the surface, the sample is exposed to [...] Read more.

During the drilling of deep ice boreholes in Central Antarctica, one of the key tasks is to collect representative samples of the borehole fluid. The principal challenge is that, during retrieval of the downhole sampler to the surface, the sample is exposed to steep negative temperature gradients, which alter its physical properties and distort the representation of the actual borehole conditions at the sampling depth. For this study, an analytical review of current downhole sampler designs was carried out. For mathematical modeling, the finite difference method was used to solve the two-dimensional axisymmetric heat conduction equation for the “fluid sample–sampler wall” system. The initial temperature distribution was adopted from thermometric data obtained in borehole 5G-5, Vostok Station. The model incorporates actual trip-speed logs recorded during tripping operations. After modeling it was established that the temperature of the near-wall layer of the sample decreases significantly faster than that of the central region and that by the time the sampler reaches the surface, the difference between the sample temperature and the temperature of the surrounding borehole fluid is substantial enough to affect rheological properties of the fluid. The developed model makes it possible to justify the introduction of corrections to the results of direct measurements of fluid properties at the wellhead. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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17 pages, 28958 KB

Open AccessArticle

Thermal Analysis of a Coil Assembly in a Nanopositioning Drive System via Reduced-Complexity CFD Modeling

by Ina Naujokat, Ludwig Herzog, Steffen Hesse and Parastoo Salimitari

Appl. Sci. 2026, 16(6), 2748; https://doi.org/10.3390/app16062748 - 13 Mar 2026

Viewed by 418

Abstract

Nanopositioning systems (NPS) are used in various fields of technology, such as micro- and nanoelectronics, optics, and biotechnology, where demands for higher dynamic performance and sub-nanometer accuracy are continuously increasing. Thus, the determination and compensation of stress-induced negative impacts on the systems gain [...] Read more.

Nanopositioning systems (NPS) are used in various fields of technology, such as micro- and nanoelectronics, optics, and biotechnology, where demands for higher dynamic performance and sub-nanometer accuracy are continuously increasing. Thus, the determination and compensation of stress-induced negative impacts on the systems gain significance to ensure accurate positioning. Major contributors are temperature gradients. Hence, understanding and predicting temperature changes is crucial for improving such systems. This work focuses on a substructure of an NPS drive system consisting of coil assemblies. This substructure serves as a primary heat source due to the occurrence of ohmic losses, leading to an increase in temperature and therefore significantly influencing the thermal deformation. The aim of this paper is to compose a CFD model with reduced submodels of the coil assembly, which, in comparison to experimental validation data, predicts its temperature development with satisfactory accuracy. By simplification of the system through a number of sub-models, computational effort is significantly lowered. The reduced CFD model not only enables efficient thermal analysis of the coil assembly but also provides a practical approach for broader use in system design and optimization, where fast and reliable thermal predictions are essential. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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17 pages, 2303 KB

Open AccessArticle

Semi-Analytical Modelling of Evaporating Power-Law Thin Films in Inclined Micro-Channels

by Husain Mustafa Nakara and Nilanjan Chakraborty

Fluids 2026, 11(3), 61; https://doi.org/10.3390/fluids11030061 - 26 Feb 2026

Viewed by 1075

Abstract

The evaporation of a thin liquid film representative of power-law rheology flowing along an inclined channel wall under the combined influence of gravity and surface tension is investigated using a semi-analytical modelling framework. The evolution of film thickness, heat transfer characteristics, and dry-out [...] Read more.

The evaporation of a thin liquid film representative of power-law rheology flowing along an inclined channel wall under the combined influence of gravity and surface tension is investigated using a semi-analytical modelling framework. The evolution of film thickness, heat transfer characteristics, and dry-out behaviour are examined as functions of the power-law exponent, Weber number, and inlet film thickness. The results show that a decrease in the power-law exponent leads to a slower reduction in film thickness, resulting in a significant increase in the dry-out length for a fixed value of consistency. This behaviour is attributed to the large effective viscosity developing near the free surface for shear-thinning fluids, in contrast to the negligible surface viscosity observed for shear-thickening fluids. The local Nusselt number increases gradually along the flow direction, followed by a sharp terminal rise marking the onset of dry-out. The mean Nusselt number decreases with increasing power-law exponent, which is consistent with the dry-out length variation with the power-law exponent. The dry-out length is found to be largely insensitive to surface tension for a fixed normalised inlet film thickness, while exhibiting an approximately linear dependence on the inlet film thickness that is nearly independent of the power-law index. Overall, the study establishes a hierarchy of controlling parameters for evaporating power-law films in inclined micro-channels, demonstrating that inlet film thickness primarily governs the dry-out location, while rheology and surface tension exert secondary influences within the parameter ranges considered. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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13 pages, 4070 KB

Open AccessArticle

Analysis of Heat Dissipation Performance for a Ventilated Honeycomb Sandwich Structure Based on the Fluid–Solid–Thermal Coupling Method

by Pengfei Xiao, Xin Zhang, Chunping Zhou, Heng Zhang and Jie Li

Energies 2025, 18(24), 6593; https://doi.org/10.3390/en18246593 - 17 Dec 2025

Cited by 2 | Viewed by 902

Abstract

In recent years, honeycomb sandwich structures have seen continuous development due to their excellent structural performance and design flexibility in heat dissipation. However, their complex heat transfer mechanisms and diverse modes of thermal exchange necessitate research on the air flow behavior and temperature [...] Read more.

In recent years, honeycomb sandwich structures have seen continuous development due to their excellent structural performance and design flexibility in heat dissipation. However, their complex heat transfer mechanisms and diverse modes of thermal exchange necessitate research on the air flow behavior and temperature distribution characteristics of micro-channels and lattice pores. This study investigates the internal flow field within a ventilated honeycomb sandwich structure through numerical simulation. The spatial flow characteristics and temperature distribution are analyzed, with a focus on the effects of turbulent kinetic energy, heat flux distribution on the heated surface, and varying pressure drop conditions on the thermal performance. The results indicate that the micro-channels inside the honeycomb core lead to a strong correlation between temperature distribution, flow velocity, and turbulence intensity. Regions with higher flow velocity and turbulent kinetic energy exhibit lower temperatures, confirming the critical role of flow motion in heat transfer. Heat flux analysis further verifies that heat is primarily removed by airflow, with superior heat exchange occurring inside the honeycomb cells compared to the solid regions. The intensive mixing induced by highly turbulent flow within the small cells enhances contact with the solid surface, thereby improving heat conduction from the solid to the flow. Moreover, as the inlet pressure increases, the overall temperature gradually decreases but exhibits a saturation trend. This indicates that beyond a certain pressure level, further increasing the inlet pressure yields diminishing returns in heat dissipation enhancement. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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28 pages, 4965 KB

Open AccessArticle

A Comparative Study Between a Lattice Boltzmann Method and a Finite Volume Method in Resolving Turbulent Heat Transfer in a Low Porosity Face-Centered Cubic Unit

by Mona Al-Mqbas, Tony Rosemann, Nico Jurtz, Harald Kruggel-Emden and Matthias Kraume

Processes 2025, 13(11), 3753; https://doi.org/10.3390/pr13113753 - 20 Nov 2025

Viewed by 1623

Abstract

Direct Numerical Simulations (DNS) are widely employed to simulate thermo-fluid dynamics in packed bed reactors, offering high-fidelity insights into complex flow and heat transfer phenomena. However, recent studies have revealed notable differences in isothermal turbulent flow results across different DNS frameworks, leaving open [...] Read more.

Direct Numerical Simulations (DNS) are widely employed to simulate thermo-fluid dynamics in packed bed reactors, offering high-fidelity insights into complex flow and heat transfer phenomena. However, recent studies have revealed notable differences in isothermal turbulent flow results across different DNS frameworks, leaving open the question of how conjugate heat transfer is affected. This study presents a comparison between DNS based on a finite volume method (FVM) and a lattice Boltzmann method (LBM) for predicting turbulent heat transfer in a low porosity face-centered cubic (FCC) packed unit. First, the methods are compared with respect to the required resolution and computational cost. Subsequently, global parameters for drag, heat transfer, and spatial as well as temporal variances are evaluated. The flow topology is further analyzed by examining the mean and fluctuating components of hydrodynamic and thermal fields. While good agreement between the methods is shown regarding time-averaged velocity and temperature profiles, more pronounced differences are observed when comparing the respective temporal variances between the two methods. Additionally, the FVM, which relies on a surface-fitted mesh, requires more degrees of freedom to obtain a grid-converged solution but delivers results of higher certainty than the LBM. These findings highlight important methodological considerations when selecting DNS approaches for resolving turbulent heat transfer in complex porous geometries. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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24 pages, 4420 KB

Open AccessArticle

Study on the Replacement of Rail Vehicle Air-Conditioning Refrigerants with Low-GWP Refrigerant Mixtures

by Yuxin Zhang, Chun Song, Jianbin Zang, Xinge Chen and Chongyu Lu

Energies 2025, 18(19), 5164; https://doi.org/10.3390/en18195164 - 28 Sep 2025

Cited by 1 | Viewed by 1399

Abstract

This study addresses the urgent demand for low-GWP refrigerant alternatives in rail vehicle air-conditioning systems by proposing a novel binary mixture, ZT01 (R13I1/R32 = 0.6/0.4 by mass), as a replacement for R407C. A comprehensive evaluation combining thermodynamic cycle modeling, refrigerant property analysis, and [...] Read more.

This study addresses the urgent demand for low-GWP refrigerant alternatives in rail vehicle air-conditioning systems by proposing a novel binary mixture, ZT01 (R13I1/R32 = 0.6/0.4 by mass), as a replacement for R407C. A comprehensive evaluation combining thermodynamic cycle modeling, refrigerant property analysis, and experimental validation shows that ZT01 delivers a coefficient of performance (COP) comparable to R407C, while providing a 45–49% improvement in volumetric cooling capacity, enabling smaller compressor displacement for the same cooling output, and reducing specific compressor work by 13–21%. In addition, ZT01 maintains a lower compression ratio, exhibits non-flammability, is compatible with POE lubricant, and has a GWP of only 308. Life Cycle Climate Performance (LCCP) analysis further indicates a 6.88% reduction in total carbon emissions and a 77.4% reduction in direct emissions compared to R407C, demonstrating that ZT01 is both technically feasible and environmentally sustainable for green retrofitting of rail vehicle HVAC systems. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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19 pages, 2371 KB

Open AccessArticle

Experimental and Simulation-Based Development of Heat-Transfer Correlations for Cyclopentane PCHE

by Xiaogang Qin, Haibo Xu, Hongfei Zhang, Ming Zhang, Lin Sun and Xuan Wang

Energies 2025, 18(11), 2744; https://doi.org/10.3390/en18112744 - 26 May 2025

Cited by 3 | Viewed by 1858

Abstract

Within the energy sector, the potential to effectively harness the considerable energy present in gas turbine waste heat via an organic Rankine cycle (ORC) could markedly improve overall energy efficiency. This investigation centers on a printed-circuit heat exchanger (PCHE) utilizing cyclopentane as the [...] Read more.

Within the energy sector, the potential to effectively harness the considerable energy present in gas turbine waste heat via an organic Rankine cycle (ORC) could markedly improve overall energy efficiency. This investigation centers on a printed-circuit heat exchanger (PCHE) utilizing cyclopentane as the working fluid. The study employs a combination of experimental techniques and computational fluid dynamics (CFD) simulations to conduct an in-depth analysis of the PCHE’s performance, leading to the successful development of a highly accurate heat-transfer correlation. A thorough comparison of experimental and simulation data is carried out to examine the temperature and pressure distributions within the heat exchanger. The maximum deviation between experimental and correlation-estimated data is within 20% (hot fluid: 15%; cold fluid: 18%). These findings offer essential theoretical insights and practical guidance for optimizing and ensuring the stable operation of waste-heat recovery systems. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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26 pages, 8989 KB

Open AccessArticle

Enhancement of Heat Transfer Using Water/Graphene Nanofluid and the Impact of Passive Techniques—Experimental, Numerical, and ML Approaches

by Javed Syed

Energies 2025, 18(1), 77; https://doi.org/10.3390/en18010077 - 28 Dec 2024

Cited by 6 | Viewed by 4157

Abstract

This study examines heat transfer characteristics by employing a combined augmentation technique that utilises nozzle-type inserts to induce swirling in water/graphene nanofluids at different concentrations. The assessment evaluates its influence on heat transfer, Nusselt number, and thermal performance factor, emphasising its applicability in [...] Read more.

This study examines heat transfer characteristics by employing a combined augmentation technique that utilises nozzle-type inserts to induce swirling in water/graphene nanofluids at different concentrations. The assessment evaluates its influence on heat transfer, Nusselt number, and thermal performance factor, emphasising its applicability in industrial contexts. This research aims to create a numerical model designed to improve the performance of heat exchangers by employing passive techniques, particularly through the implementation of a convergent–divergent nozzle insert, without the need for experimental validation. The accuracy of the model is confirmed through experimental data, and it is subsequently employed to simulate various Reynolds numbers, generating datasets for training and testing machine learning models. This study also highlights the potential aggregation and flow resistance limitations when combining nanoparticles with passive inserts. The experimental outcomes for the convergent nozzle insert are employed to validate the supervised machine learning model. Subsequently, a numerical analysis of the convergent–divergent nozzle insert is conducted using approximately 220 samples for training and testing purposes. The convergent–divergent nozzle insert improves heat transfer efficiency in heat exchangers by generating high-velocity flow and enhancing temperature gradients. Optimising nozzle geometry through numerical simulations can determine the ideal dimensions for better heat transfer rates. Nanofluids show a thermal performance factor increase of up to 13.2% at higher inlet temperatures than water. The thermal performance factor for nanofluid at inlet higher temperatures is 8.5%, 9.3%, 11.6%, 12.8%, and 13.2% compared to water. Full article

(This article belongs to the Topic Heat and Mass Transfer in Engineering)

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