Article
Thermodynamics
Latif Aref, Rasoul Fallahzadeh, Seyed Reza Shabanian, Mojtaba Hosseinzadeh
Summary: The study aims to increase the thermal efficiency of a flat plate closed-loop pulsating heat pipe solar collector by introducing a novel closed-loop pulsating heat pipe (CLPHP) with a dual-diameter structure. Experimental results show that the thermal performance of the dual-diameter configuration is considerably better than the single-diameter in different inclination angles, achieving a thermal efficiency of 72.4% under sunny weather conditions.
Article
Thermodynamics
Guowei Xiahou, Shun Zhang, Rui Ma, Junjie Zhang, Yecong He
Summary: A novel heat pipe radiator is proposed for efficient heat dissipation of high heat flux density chips with different installation angles. The optimal inclination angle is found to be 60 degrees, with strong heat transfer capability. Different inclination angles impact the performance, with the power influencing fluctuations in heat source temperature deviation.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Jiansheng Wang, Yu Pan, Xueling Liu
Summary: The study shows that the start-up and heat transfer performance of pulsating heat pipes (PHP) is significantly affected by inclination angle and the structure of variable diameter can reduce the sensitivity of PHP to gravity. Furthermore, PHP with variable diameter structure can even exhibit start-up phenomena with horizontal arrangement.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Rostam Akbari Kangarluei, Majid Abbasalizadeh Ranjbari, Ahad Ramezanpour
Summary: The study found that under the same input heat condition, Inner-Grooved Pulsating Heat Pipes (IGPHP) have lower thermal resistance and higher effective thermal conductivity compared to Smooth Pulsating Heat Pipes (SPHP); the average reduction of thermal resistance of IGPHP compared to SPHP is more significant, especially at the angle of 5 degrees.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Koji Fumoto, Keiko Ishii
Summary: A study found that highly efficient heat transport can be achieved when the filling ratio of a pulsating heat pipe (PHP) is extremely low. The experiment used a flat aluminum tube with 28 straight channels and obtained a minimum thermal resistance of 0.021 K/W and a temperature difference of less than 1.0 K between the evaporating and condensing sections.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Maria Barba, Romain Bruce, Florent Bouchet, Antoine Bonelli, Bertrand Baudouy
Summary: The study on cryogenic pulsating heat pipes for cooling superconducting devices involved heat load tests with different filling ratios using neon, argon, and nitrogen as working fluids. The tests showed that the optimal filling ratios are usually below 50%, highlighting the crucial role of fluid circulation in global heat transfer. Excess liquid at high filling ratios impedes fluid circulation and reduces heat transfer efficiency in the pulsating heat pipes.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Latif Aref, Rasoul Fallahzadeh, Vahid Madadi Avargani
Summary: This study aims to improve the performance of a solar energy-driven HDH desalination system by using a closed-loop pulsating heat pipe (CLPHP) in combination with a bubble basin. The experimental results show that the bubble basin type has a higher yield compared to the bubble column type, and increasing radiation and air mass flow rate can enhance productivity. The maximum yield achieved by the proposed system is 8.7 L/(day.m(2)).
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Energy & Fuels
Niti Kammuang-Lue, Chinphat Patanathabutr, Phrut Sakulchangsatjatai, Pradit Terdtoon
Summary: This research aimed to investigate the thermal characteristics of a rotating closed-loop pulsating heat pipe (RCLPHP) for integrating into rotating-type energy storage devices. The study observed the thermal characteristics from the start-up state to the post-critical state. It found that the RCLPHP exhibited temperature fluctuations in the evaporator and condenser sections during normal operation, and the internal phenomena of the working fluid resembled a slug-train. When the RCLPHP reached the critical state, the condenser section temperature subsequently decreased.
Article
Green & Sustainable Science & Technology
Weixiu Shi, Xuebing Liu, Xiaoyang Su, Hongdi Chen, Lisheng Pan
Summary: Pulsating heat pipe (PHP) is an efficient heat transfer technology used in heat dissipation and energy utilization. Factors affecting its heat transfer include working fluid, filling ratio, and inclination angle. The cooling capacity of the cooling water system at the condensing section is an important factor affecting the starting and operating of PHP. Studying PHP under different cooling water flow rates is significant for enhancing its performance.
Article
Energy & Fuels
Niti Kammuang-lue, Phrut Sakulchangsatjatai, Pradit Terdtoon
Summary: This experimental study focuses on the thermal performance and temperature variation of the closed-loop pulsating heat pipe (CLPHP) influenced by different adiabatic section lengths. The results suggest that the adiabatic section length has varying effects on heat flux, depending on the properties of the working fluid.
Article
Thermodynamics
Sizhuo Li, Haiyue Pei, Dongli Liu, Yunwei Shen, Xuan Tao, Zhihua Gan
Summary: An experimental setup for visualizing a nitrogen pulsating heat pipe (PHP) was developed. The PHP, fabricated using MEMS technology, has a hydraulic diameter of 667 μm and overall dimensions of 70 x 25 x 2 mm³. Six different filling ratios (FRs) ranging from 15% to 94% were measured using visualization images, with the PHP failing to start-up only at a 15% FR. Flow images of nitrogen PHPs were obtained for the first time, revealing four flow patterns. The variations of flow characteristics and fluid motion with heat loads and FRs were analyzed, and the fluid motion diagram and flow pattern proportion were extracted from the visualization results. The study found that large amplitude oscillating motion is rarely observed in the nitrogen PHP, and annular flow dominates in low and medium FR working conditions, suggesting that the one-dimensional slug flow model may have a limited application range for the flat-plate nitrogen PHP.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Xiang Gou, Guangyao Li, Ruichen Zhang, Chongxin Jian, Qiyan Zhang, Bao Li, Qixuan Dong
Summary: This study investigates the critical and optimal inclination angles of TPCT under different working conditions, as well as the improvement of TPCT performance with increasing heating power. The results provide references for enhancing heat pipe performance and related applications, and also offer experimental basis for performance changes in TPCT applications when accidental dry burning occurs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Sizhuo Li, Zhicheng Bu, Tiegen Fang, Yubo Wang, Yunwei Shen, Xuan Tao, Bo Jiao, Zhihua Gan
Summary: A simultaneous thermal and visual experiment was conducted on a silicon-based flat-plate nitrogen pulsating heat pipe (PHP) for the first time. The start-up and quasi-steady state performances were analyzed, revealing two types of start-up processes and different degrees of thermal performance hysteresis phenomenon. The optimal thermal resistance was found to be lower in a lower filling ratio working condition, while a lower filling ratio resulted in a lower heat transfer limit. The latent heat transfer efficiency in the nitrogen PHP was inferred to be higher than that of the sensible heat transfer.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
L. H. Saw, M. C. Yew, M. K. Yew, W. T. Chong, H. M. Poon, W. S. Liew, W. H. Yeo
Summary: This study introduces a closed loop pulsating heat pipe (CLPHP) roof cooling system, which is investigated for its thermal performance through experiments and comparison. The experiment results show that the cool roof system with CLPHP technology can significantly lower the attic temperature compared to the bare metal roof design, making it a promising method for improving thermal comfort in buildings.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Rongji Xu, Xiaona Li, Taoming Lei, Qingping Wu, Ruixiang Wang
Summary: By introducing a gravity pulsating heat pipe (GPHP), the gravity effect of the working fluid (WF) can be enhanced to increase the heat transfer limit and solve the dry-up issue in a conventional pulsating heat pipe (PHP) under high heat input. Experimental investigation of the GPHP using HFE-750 0 as the WF under different heat inputs (30-230 W) revealed three heat transfer stages: low heat-input steady-state operation, transition, and high heat-input steady-state operation. The GPHP exhibited quick and stable heat transfer performance at low heat input, while in the transition stage, the accumulation of liquid WF and the formation of a stable vapor film hindered heat transfer. Under high heat input, the liquid WF returned to the evaporative section, resulting in stable heat transfer with increasing latent heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(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)