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Dear Colleagues,

Heat flows and mass transport through porous and non-porous media signify one of the most active areas of research in modern energy engineering. The focus of this Special Issue is on the current state of research and education in computational and experimental studies of combined heat and mass transfer.

Manuscripts to be included in the Special Issue should therefore concentrate on a range of topics including diffusion; forced convection; natural convection; mixed convection; combined processes; and other industrial applications.

We would also welcome research on heat transfer enhancement in heat exchangers and fluidized beds and on the practical use of thermodynamic methods in the design and optimization of these systems.

A broad outline of this Special Issue’s scope includes peer-reviewed original research articles, technical reports, review papers, short communications, and notes to the editor. Thus, high-quality research papers or reviews dealing with any aspect of heat and mass transfer are welcomed. Papers may be theoretical, numerical, or experimental.

Dr. Maryam Ghodrat
Dr. Amin Shahsavar
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

heat transfer
mas transfer
computational fluid dynamics
heat exchanger
thermal management

Published Papers (2 papers)

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Research

13 pages, 3824 KiB

Open AccessArticle

A Comparative Thermal and Economic Investigation of Similar Shell & Tube and Plate Heat Exchangers with Low Concentration Ag-H₂O Nanofluid

by Seyed Hadi Pourhoseini, Mojtaba Baghban and Maryam Ghodrat

Energies 2023, 16(4), 1854; https://doi.org/10.3390/en16041854 - 13 Feb 2023

Cited by 1 | Viewed by 1167

Abstract

Plate Heat Exchanger (PHE) and Shell and Tube Heat Exchanger (STHE) with identical heat transfer areas and material characteristics are proposed and a comparative thermal and economic comparative analysis is carried out on both exchangers. Ag-water nanofluid is used at low concentrations (0, 2.5, 5, 10 mg/L), flow rates (2, 5, and 8 L/min), and inlet temperatures (36, 46, and 56 °C) as hot flow and the heat transfer coefficient (U), electrical power consumption of the pump, and costs per unit of average U value are considered as the calculated parameters for each heat exchanger in co-current and counter-current flows. The results revealed that PHE generates a higher U value compared to the STHE under different Ag-water nanofluid concentrations. This is due to the existence of grooves on the plates of PHE which generates turbulent flow. The impact of nanofluid concentration on U is negligible for lower concentrations in both PHE and STHE. It is also found that the nanofluid flow rate has the highest impact on the U value, just like conventional fluid. Besides, even though counter-current flow increases the U values for both PHE and STHE, the flow pattern has a higher impact on the U value of PHE than that of STHE. For both PHE and STHE, increasing the nanofluid flow rate enhances the amount of U. However, the effect of flow rate on the U value of PHE is greater than that of the STHE. It is also shown that throughout the entire experimental temperature domain, PHE has had higher performance than STHE, and as the fluid temperature increased from 36 to 56 °C, there was a slight increase in the overall heat transfer of both PHE and STHE. Furthermore, for the same flow rate, both PHE and STHE had almost the same pump power consumption, and increasing the nanofluid flow rate from 2 L/min to 8 L/min promoted the electrical power consumption of the pump. Finally, we found that the costs per unit of heat transfer coefficient for PHE are significantly lower than STHE. The presented results also indicated that using a vortex generator at the inlet of STHE tubes, to form turbulent flow, increases the U values of STHE for both co-current and counter-current flows but these U values are lower than the corresponding U values of PHE. Small plates gap in PHE structure cause higher fluid flow velocities and create a chain-like structure of nanoparticles (NPs) between PHE’s plates (especially at higher nanofluids concentrations). Full article

(This article belongs to the Special Issue Review and Recent Advances in Computational and Experimental Heat and Mass Transfer)

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25 pages, 4309 KiB

Open AccessArticle

Numerical Simulation of the Influence of Hydrogen Concentration on Detonation Diffraction Mechanism

by Mohammad Hosein Shamsadin Saeid and Maryam Ghodrat

Energies 2022, 15(22), 8726; https://doi.org/10.3390/en15228726 - 20 Nov 2022

Cited by 1 | Viewed by 1415

Abstract

In this study, the impact of hydrogen concentration on deflagration to detonation transition (DDT) and detonation diffraction mechanisms was investigated. The combustion chamber was an ENACCEF facility, with nine obstacles at a blockage ratio of 0.63 and three mixtures with hydrogen concentrations of 13%, 20%, and 30%. Detonation diffraction mechanisms were numerically investigated by a density-based solver of OpenFOAM CFD toolbox named ddtFoam. In this simulation, for the low Mach numbers, the pddtFoam solver was applied, and for high speeds, the pddtFoam solver switched to the ddtFoam solver to simulate flame propagation without resolving all microscopic details in the flow in the CFD grid, and to provide a basis for simulating flame acceleration (FA) and the onset of detonation in large three-dimensional geometries. The results showed that, for the lean H₂–air mixture with 13% hydrogen concentration, intense interaction between propagating flame and turbulent flow led to a rapid transition from slow to fast deflagration. However, the onset of detonation did not occur inside the tube. For the H₂–air mixture with 20% hydrogen concentration, the detonation initiation appeared in the acceleration tube. It was also found that following the diffraction of detonation, the collision of transverse waves with the wall of the tube and the reflection of transverse waves were the most essential and effective parameters in the re-initiation of the detonation. For the H₂–air mixture with 30% hydrogen concentration, the detonation initiation occurred while passing through the obstacles. Subsequently, at detonation diffraction, the direct initiation mechanism was observed. Full article

(This article belongs to the Special Issue Review and Recent Advances in Computational and Experimental Heat and Mass Transfer)

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