Article
Thermodynamics
Mauro Abela, Mauro Mameli, Vadim Nikolayev, Sauro Filippeschi
Summary: The start-up process of a large diameter Pulsating Heat Pipe (PHP) specially designed for future experiments on the International Space Station (ISS) has been numerically simulated and compared with the results obtained during a parabolic flight campaign. The numerical simulation results agree with the experimental results, providing useful information for the correct design of the engineering model.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Mohammad Hossein Zolfagharnasab, Mona Zamani Pedram, Kambiz Vafai
Summary: In this study, a single-phase approach is used for the numerical simulation of heat pipe analysis, simplifying the numerical setup and improving convergence stability and solution time.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Cristiano Enke, Jorge Bertoldo Junior, Valeri Vlassov
Summary: The study investigated the influence of NCG on the performance of axially-grooved ammonia heat pipes, developing a mathematical model for simulation and conducting experiments to validate it. The results showed that NCG distorts the temperature profile of the pipes and that temperature change rate can be used for more sensitive detection of small amounts of NCG.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Xiao Sun, Sizhuo Li, Bo Wang, Bo Jiao, John Pfotenhauer, Franklin Miller, Zhihua Gan
Summary: A one-dimensional numerical model based on slug flow is developed to predict the thermal performance of cryogenic PHPs, demonstrating good predictive ability. The study shows that the response time of the hydrogen PHP to heat load changes is less than 5 s, and the vapor bubbles in the evaporator can be in a superheated state with similar proportions of sensible heat and latent heat in heat transfer.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Engineering, Civil
Jiayi Cheng, Jianbo Han, Binghui Zheng, Xiaomeng Wang, Zhengxian Yang, Xiaoxia Zhang
Summary: Polycyclic aromatic hydrocarbons (PAHs) are crucial pollution factors in the marine environment, and their water exchange rate significantly affects their distribution in sediments. Areas closer to the bay-head with lower water exchange rates are more prone to the formation of high concentration areas of PAHs in sediments.
JOURNAL OF HYDROLOGY
(2021)
Article
Chemistry, Multidisciplinary
Kangli Bao, Yuan Zhuang, Xu Gao, Yuanyuan Xu, Xilei Wu, Xiaohong Han
Summary: A study using a new numerical model found that different lengths of adiabatic sections have significant effects on the performance of pulsating heat pipes, with shorter adiabatic section length benefiting start-up performance. At high heat input, pulsating heat pipes with longer adiabatic section lengths exhibit lower thermal resistance.
APPLIED SCIENCES-BASEL
(2021)
Article
Mathematics, Applied
S. E. Ghasemi, A. A. Ranjbar
Summary: This research investigates the performance of microchannel with different protrusions through numerical thermal analysis. Computational fluid dynamics is used to simulate four different configurations of circular protrusions. Deionized water is used as the working fluid, and its thermal-physical properties depend on temperature. The finite volume method is employed to solve the governing equations of laminar fluid flow in steady state condition. The numerical simulation results show good agreement with experimental data. It is found that using protrusions on the bottom wall improves the thermal criteria in microchannels. The influence of protrusions on heat transfer coefficient and Nusselt number ratio compared to a smooth channel is evaluated at different fluid velocities. An important finding is that a microchannel with larger protrusion radius has better heat transfer rate.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Thermodynamics
Takuya Adachi, Xinyu Chang, Hiroki Nagai
Summary: Loop heat pipes (LHPs) are efficient two-phase heat transfer devices widely used in spacecraft thermal control. A new steady-state model was developed to investigate the effect of nucleate boiling in the evaporator core, and the conditions under which nucleate boiling does not occur were identified.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Farshad Farahbod
Summary: This research investigates the application of nanoparticles for cooling in drilling operations and derives a mathematical model for predicting temperature distribution. Experimental results show that injecting nanofluids into heat pipes significantly reduces temperature distribution, with the optimal ratio of heat pipe diameter to drill diameter being around 0.12.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Construction & Building Technology
Yu Mingzhi, Lu Wei, Zhang Fangfang, Zhang Wenke, Cui Ping, Fang Zhaohong
Summary: This study presents a novel simple model for simulating the heat transfer of mid-deep buried U-bend pipe ground heat exchangers. The model showed that heat extraction capacity increased with the increase of ground thermal conductivity, ground volumetric heat capacity, buried pipe depth, and horizontal pipe length. The study also found that the heat extraction capacity of MBUGHE decreased significantly in the initial years, but gradually stabilized after 15 years of operation.
ENERGY AND BUILDINGS
(2021)
Article
Thermodynamics
Peng Lu, Xiaodie Yan, Rong Wu, Shaozheng Wang, Hulin Huang
Summary: This paper focuses on the design and analysis of space radiators, with particular emphasis on the numerical modeling of heat pipes and fins. By simulating the phase-change heat transfer process inside the heat pipes and studying the influence of fin size on heat dissipation performance, the optimal dimensions for both heat pipes and fins are determined. Finally, the heat pipes and fins are assembled into a complete radiative cooling system, with a low mass-area ratio and high total heat dissipation power.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Thermodynamics
Lianjie Zhang, Changshun Du, Hongtao Wang, Jian Zhao
Summary: The purpose of this study is to understand the heat transfer and flow law of waxy crude oil in inclined pipelines and provide theoretical guidance for safe pipeline operation. Three-dimensional numerical simulations were conducted for pipes with inclination angles of 0 degrees, 25 degrees, and 45 degrees using CFD software. The temperature and velocity fields of waxy crude oil and the cooling gelation law were found to be similar in different cases. The horizontal pipeline experienced a gradual decrease in average temperature along the flow direction, while the inclined pipeline exhibited a gradual temperature decrease along the downward direction of inclination.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Enpei Wang, Lei Li
Summary: In this study, the thermal behavior performance of a heat pipe with potassium as the working fluid and a capillary wick structure was investigated under marine conditions using numerical simulations. A CFD model was developed using user-defined functions (UDFs) to account for the physical properties of potassium and the additional force method of rolling motion. The model was validated with experimental results and used to analyze the influence of parameters such as inclination angle, filling ratio, and rolling period on the temperature distribution and thermal resistance of the heat pipe. The results were visualized through phase change and wall temperature distribution charts obtained from CFD simulations. The findings provide valuable insights for the design and evaluation of high temperature heat pipe applications in marine environments.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Han Wang, Shunqi Wang, Jinguang Zang, Junfeng Wang, Yanping Huang
Summary: Direct numerical simulation was used to study the heat transfer of SCO2 in a semicircular pipe under mixed and forced convection. The study revealed significant effects of secondary flow, thermal acceleration, corner effect, and geometric orientation on heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Chunhua Min, Xiaomeng Gao, Fei Li, Kun Wang
Summary: Proton exchange membrane fuel cell (PEMFC) can be effectively cooled by air cooling, liquid cooling, and pulsating heat pipe cooling. The results show that both liquid cooling and pulsating heat pipe cooling can effectively reduce the temperature of the PEMFC, with higher indices of uniform temperature compared to air cooling.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(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
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
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
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
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)