Di Qiu^1,3,4, Rongpei Shi^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 1017-1028, 2024, DOI:10.32604/cmes.2024.048797

Abstract For media with inclusions (e.g., precipitates, voids, reinforcements, and others), the difference in lattice parameter and the elastic modulus between the matrix and inclusions cause stress concentration at the interfaces. These stress fields depend on the inclusions’ size, shape, and distribution and will respond instantly to the evolving microstructure. This study develops a phase-field model concerning modulus heterogeneity. The effect of modulus heterogeneity on the growth process and equilibrium state of the α plate in Ti-6Al-4V during precipitation is evaluated. The α precipitate exhibits strong anisotropy in shape upon cooling due to the interplay of the elastic strain and interfacial… More >

Inga Zotova^1,*, Edgars Kirilovs¹, Laura Ziemele²

Journal of Renewable Materials, Vol.12, No.3, pp. 603-613, 2024, DOI:10.32604/jrm.2024.047607

Abstract Nowadays buildings contain innovative materials, materials from local resources, production surpluses and rapidly renewable natural resources. Phase Change Materials (PCM) are one such group of novel materials which reduce building energy consumption. With the wider availability of microencapsulated PCM, there is an opportunity to develop a new type of insulating materials, combinate PCM with traditional insulation materials for latent heat energy storage. These materials are typically flammable and are located on the interior wall finishing yet there has been no detailed assessment of their fire performance. In this research work prototypes of low-density insulating boards for indoor spaces from hemp… More > Graphic Abstract

KEMIN WANG, LIFEI HE

Journal of Polymer Materials, Vol.36, No.3, pp. 253-260, 2019, DOI:10.32381/JPM.2019.36.03.5

Abstract This study proposes a simple approach for the fabrication of microspherical catalysts with a hierarchical porous structure. The cross-linked porous microspheres with catalytic ability were prepared directly from small-molecular monomers via low-temperature phase-separation photopolymerization of water/oil suspension. The morphology, pore size, chemical structure, and thermal stability of the obtained porous microspheres were characterized by SEM, Mercury Intrusion Porosimetry, FTIR, and TGA. The porous microspheres directly served as an acid catalyst for the condensation reaction of benzaldehyde and ethylene glycol, which exhibited superior catalytic activity and recyclability. The results indicated that such porous microspheres have great potential in the application of… More >

XIAOYAN LIU^a,*, XU CHEN^a, HONGXING ZHANG^b, CHANGJUN ZHANG^a, SHIYUAN YANG^a, GUANGQUAN LI^a

Journal of Polymer Materials, Vol.36, No.2, pp. 121-132, 2019, DOI:10.32381/JPM.2019.36.02.2

Abstract In this work, three in situ impact polypropylene copolymer(IPC) samples were prepared through Ziegler-Natta catalyst only changing the feed composition (ethylene to ethylene and propylene molar ratio, C2/C2+C3) in gas-phase polymerization reactor. Polymer (IPC) were characterical by solvent classification, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), successive self-nucleation and annealing (SSA), nuclear magnetic resonance(13C-NMR) and scanning electron microscopy(SEM). The mechanical properties of IPC samples were tested.The results indicate that with similar ethylene content, the feed composition which determines the content and structure of EPR and EbP component in IPC, further impacts the rubber phase size and distribution in IPC,… More >

Karim Choubani^1,2,*, Ons Ghriss³, Nashmi H. Alrasheedi¹, Sirin Dhaoui², Abdallah Bouabidi²

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 341-358, 2024, DOI:10.32604/fhmt.2024.047016

Abstract Faced with the world’s environmental and energy-related challenges, researchers are turning to innovative, sustainable and intelligent solutions to produce, store, and distribute energy. This work explores the trend of using a smart sensor to monitor the stability and efficiency of a salt-gradient solar pond. Several studies have been conducted to improve the thermal efficiency of salt-gradient solar ponds by introducing other materials. This study investigates the thermal and salinity behaviors of a pilot of smart salt-gradient solar ponds with (SGSP) and without (SGSPP) paraffin wax (PW) as a phase-change material (PCM). Temperature and salinity were measured experimentally using a smart… More >

Liqun Zhou^1,*, Weilin Yang¹, Chaojie Li², Shi Lin³

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 157-173, 2024, DOI:10.32604/fhmt.2023.045135

Abstract The power density of electronic components grows continuously, and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability, reliability and service life. Therefore, achieving efficient cooling in limited space has become a key problem in updating electronic devices with high performance and high integration. Two-phase immersion is a novel cooling method. The computational fluid dynamics (CFD) method is used to investigate the cooling performance of two-phase immersion cooling on high-power electronics. The two-dimensional CFD model is utilized by the volume of fluid (VOF) method and Reynolds Stress Model. Lee’s model was employed to calculate the phase change… More > Graphic Abstract

Chen Fang^*, Milnes David, Anita Rogacs, Kenneth Goodson

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-11, 2010, DOI:10.5098/hmt.v1.1.3002

Abstract Vapor-venting microchannel heat exchangers are promising because they address the problems of high pressure drop, flow instability, and local dryout that are common in conventional two-phase microchannel heat sinks. We present a 3D numerical simulation of the vapor-venting process in a rectangular microchannel bounded on one side by a hydrophobic porous membrane for phase-separation. The simulation is based on the volume of fluid (VOF) method together with models for interphase mass transfer and capillary force. Simulation shows the vapor-venting mechanism can effectively mitigate the vapor accumulation issue, reduce the pressure drop, and suppress the local dry-out in the microchannel. Pressure… More >

A. Valan Arasu^a,*, Agus P. Sasmito^b,†, Arun S. Mujumdar^b

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-7, 2011, DOI:10.5098/hmt.v2.4.3005

Abstract The heat transfer enhancement of paraffin wax, a cheap and widely used latent heat thermal energy storage material, using nanoparticles is investigated. The effects of nanoparticle volume fraction on both the melting and solidification rates of paraffin wax are analysed and compared for Al₂O₃ and CuO nanoparticles. Present results show that dispersing nanoparticles in smaller volumetric fractions increase the heat transfer rate. The enhancement in thermal performance of paraffin wax is greater for Al₂O₃ compared with that for CuO nanoparticles. More >

M. Yakut Ali^a,*, Fanghao Yang^a, Ruixian Fang^a, Chen Li^a, Jamil Khan^a,†

Frontiers in Heat and Mass Transfer, Vol.2, No.3, pp. 1-11, 2011, DOI:10.5098/hmt.v2.3.3003

Abstract This study experimentally investigates single phase heat transfer and pressure drop characteristics of a shallow rectangular microchannel heat sink whose surface is enhanced with copper nanowires (CuNWs). The hydraulic diameter of the channel is 672 μm and the bottom wall is coated with Cu nanowires (CuNWs) of 200 nm in diameter and 50 μm in length. CuNWs are grown on the Cu heat sink by electrochemical synthesis technique which is inexpensive and readily scalable. The heat transfer and pressure drop results of CuNWs enhanced heat sink are compared with that of bare copper surface heat sink using deionized (DI) water… More >

Jing Huang, Kapil Baheti, J. K. Chen^*, Yuwen Zhang

Frontiers in Heat and Mass Transfer, Vol.2, No.1, pp. 1-10, 2011, DOI:10.5098/hmt.v2.1.3005

Abstract An axisymmetric model for thermal transport in thin metal films irradiated by an ultrashort laser pulse was developed. The superheating phenomena including preheating, melting, vaporization and re-solidification were modeled and analyzed. Together with the energy balance, nucleation dynamics was employed iteratively to track the solid-liquid interface and the gas kinetics law was used iteratively to track the liquid-vapor interface. The numerical results showed that higher laser fluence and shorter pulse width lead to higher interfacial temperature, larger melting and ablation depths. A simplified 1-D model could overestimate temperature response and ablation depth due to the omission of radial heat conduction. More >