Article
Thermodynamics
Joe Hajjar, Sabine Enders
Summary: A generalized theoretical framework is introduced for multicomponent reactive nonuniform systems, combining the modified and generalized Cahn-Hilliard equation with a chemical kinetics model. The framework allows for the modelling and investigation of the combined reaction and diffusion in reactive liquid-liquid systems. It is found that for reacting mixtures with much smaller reaction rates than diffusion rates, the mixture will remain in phase equilibrium upon reaction and the interfacial chemical reaction will not affect the overall system dynamics, which are only influenced by the kinetics of the bulk phases.
FLUID PHASE EQUILIBRIA
(2024)
Article
Thermodynamics
F. J. dos Santos, G. S. M. Martins, M. Strobel, L. Beckedorff, K. V. de Paiva, J. L. G. Oliveira
Summary: This study investigates the effects of inlet conditions and plate's features on the thermal-flow performance of a gasket plate heat exchanger (GPHE) and assesses the impact of a modified tightening distance on its performance. No systematic study on the combined effects of inlet conditions and assembly accuracy on GPHE performance has been conducted before.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Peter Englezos
Summary: This article discusses the research progress and challenges in the field of canonical clathrate or gas hydrate phase equilibria, as well as the application of computational methods and models. It also explores the potential of machine learning techniques in hydrate and thermodynamic calculations.
FLUID PHASE EQUILIBRIA
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Alok K. Ray, Dibakar Rakshit, K. Ravi Kumar, Hal Gurgenci
Summary: The low thermal conductivity of phase change materials limits the heat transfer rate and application of latent heat storage systems. This numerical study examines the impact of two passive heat transfer enhancement techniques on the thermal performance of a latent heat storage system. The results show that the orientation and position of the heat transfer fluid tube have significant effects on the charging duration, while the discharging duration remains unchanged. The combined effect of orientation and eccentricity reduces the charging duration, but increases the discharging duration compared to the concentric domain.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Bostjan Zajec, Blaz Mikuz, Anil Kumar Basavaraj, Marko Matkovic, Matej Tekavcic, Martin Draksler, Leon Cizelj, Bostjan Koncar
Summary: We have developed an advanced experimental setup to investigate flow and heat transfer in an annular channel. The setup allows heat transfer measurements and flow visualization using a temperature-controlled inner tube. Measurements can be conducted in both single-phase and two-phase flow regimes. The setup ensures a uniform velocity field in the annular channel using specially designed inlet and outlet headers. The inner copper tube is heated by water and contains turbulators for enhanced heat transfer and thermocouples for temperature measurement. A three-dimensional conjugate heat transfer CFD model has been developed and validated to accurately estimate heat losses in the setup. This study demonstrates the importance of numerical simulations in improving the interpretation of complex experimental results.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Weijie Chen, Ke Wang, Yongqing Wang, Shantung Tu, Zunchao Liu, Huijuan Su
Summary: In this study, a novel gradient porosity transpiration cooling plate structure (GP-TCPS) is proposed to alleviate heat transfer deterioration caused by non-uniform temperature distribution in transpiration cooling plate structure (TCPS). Computational fluid dynamics (CFD) and response surface method (RSM) were used for qualitative and quantitative analysis of the flow and heat transfer of GP-TCPS. The optimized structure of GP-TCPS significantly improves temperature uniformity, injection pressure, and average cooling efficiency compared to traditional TCPS.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Qilong Liu, Dongbo Shi, Di Zhang, Yonghui Xie
Summary: This study aims to reduce pressure loss and improve flow uniformity by inserting connecting bridges of varying sizes in the mid-chord region of gas turbine blades. The suitability and performance of different connecting bridge combinations are evaluated through simulations. The results show that the incorporation of connecting bridges leads to a significant reduction in flow resistance and an increase in thermal performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jiao Chen, Guofu Chen, Zhaoliang Wang, Dawei Tang
Summary: This study investigates the phonon transport processes at heterointerfaces and reveals their dependence on Al atom concentration and compressive strain. The research shows that the introduction of Al atoms and compressive strain enhance phonon-interface scattering and promote phonon transport at the heterointerface.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Datta Prasad, Susmita Dash
Summary: In this study, a theoretical model is proposed to determine the total heat transfer to a Leidenfrost droplet on microtextured substrates, considering the curved shape of the liquid-vapor interface. The results show that the vapor gap and flow field beneath the Leidenfrost droplet on a microtextured substrate depend on the substrate morphology, and the shape of the liquid-vapor interface influences the evaporation rate on the substrate.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Tan Lo Wong, Ke Ma, Chamil Abeykoon
Summary: This study explored the thermal properties of polyethylene glycol (PEG)-based composites by incorporating different types of carbon-based fillers. The addition of milled carbon fibre greatly improved the thermal conductivity, while graphite filler showed excellent performance in thermal diffusivity and cyclability.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
A. R. Khoei, A. M. Orvati Movaffagh, A. Rezaei Sameti
Summary: This paper presents a comprehensive study on the thermo-mechanical characteristics of oxide-coated aluminum nano-powder. It is found that the thermal conductivity of oxide-coated aluminum nano-powder is significantly lower than that of the bulk aluminum, and it is affected by the density and temperature.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jie Li, Dalin Zhang, Yubing Wang, Penglei Zhang, Guangya Zhu
Summary: This paper presents an experimental study of flow condensation of R134a in a multiport mini channel and a mini channel with pin fin array. The results show that the pin fin array significantly improves the condensation heat transfer coefficient, and the local heat transfer coefficient increases with vapor quality, mass flux, and heat flux while decreases with saturation pressure.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shao-Fei Zheng, We-Kai Liana, Jia-Xing Meng, He-Chen Wang, Shu-Rong Gao, Yan-Ru Yang, Hai-Wang Li, Bengt Sunden, Xiao-Dong Wang
Summary: This study focuses on optimizing the rib arrangements in cooling passages of a turbine blade cooling unit to improve heat transfer performance. The multi-parameter optimization algorithm is applied to find the optimal designs with different performance indices as objective functions. The results show that using the overall performance factor as the objective function can achieve significant reduction in friction loss with moderate heat transfer loss.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Mostafa Taha, Song Zhao, Aymeric Lamorlette, Jean-Louis Consalvi, Pierre Boivin
Summary: For the first time, large-eddy simulations (LES) of the near-field region of large-scale fire plumes were performed using a pressure-based Lattice Boltzmann method (LBM) with low-Mach number approximation. The simulations showed quantitative agreement with experimental data and were consistent with previously-published numerical studies. The study demonstrated the computational efficiency of the proposed LBM solver in tackling fire-induced flows, suggesting LBMs as a good alternative candidate for modeling fire-related problems.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Wen Li, Jingxin Wang, Linlin Tian, Chuling Zhu, Ning Zhao
Summary: The rebound dynamics of a microscale supercooled water droplet on a cold superhydrophobic surface were numerically studied. Four different regimes were observed during the impacting-freezing process, and the results were affected by the cold surface temperature, impact velocity, droplet diameter, and supercooled degree.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xuan Wang, Chen Kong, Minghao Ren, Aihan Li, Juntao Chang
Summary: This study proposes a fast-predicting scheme for the temperature distribution of aeroengine combustor using deep learning. Different network structures are trained and compared to predict the temperature field under different dataset processing methods. The results show that fully-connected networks and fusion convolutional networks have good predictive capabilities. Introducing reference data to process the dataset significantly improves the models' prediction ability for equivalent ratio conditions far from the training dataset.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Wei Su, Dongxu Ma, Xu Jin, Zhongyan Liu, Dahai Zhao
Summary: Frost formation is a complex nonlinear physical process, and the inclination angle and surface wettability have significant effects on the frosting and defrosting characteristics.
APPLIED THERMAL ENGINEERING
(2024)
