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
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
Est Dev Patel, Subrata Kumar
Summary: The thermal performance of an asymmetric single-turn closed-loop pulsating heat pipe (aCLPHP) was experimentally investigated. The working fluids exhibited a two-phase oscillatory-circulatory flow in the asymmetric closed-loop due to the capillary pressure difference. The use of adiabatic channels of different cross-sections resulted in a pressure difference, enhancing the flow of heated vapor and liquid. The asymmetry increased the heat carrying capacity for water and acetone by 75% and 50% respectively. The introduction of an asymmetric adiabatic section is a simple and cost-effective approach to improve the capability of a single-turn CLPHP for thermal management.
APPLIED THERMAL ENGINEERING
(2023)
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
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
S. Rudresha, E. R. Babu, R. Thejaraju
Summary: This study investigated the two-phase system of a pulsating heat pipe, taking into account useful heat transfer. The experimental results showed that the thermal resistance decreases gradually with an increase in heat transfer rate, with the lowest resistance observed at a fill ratio of 55%. The heat transfer performance of ethylene glycol was good, exhibiting improvement compared to CFD results.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
M. Ahmadian-Elmi, M. R. Hajmohammadi, S. S. Nourazar, K. Vafai, M. B. Shafii
Summary: This study conducted a three-dimensional modeling of a pulsating heat pipe and investigated the effects of physical and geometrical parameters such as filling ratio, transverse distance, and the number of loops on its performance. The heat pipe was assumed to be embedded in the microchannel heat sink with its thermal condition. The volume of fluid multiphase flow model was used in the numerical analysis. Different values of filling ratio, transverse distance, and number of loops were considered and compared. The results showed that a filling ratio of 60% had the best performance and a transverse distance of 18mm had the lowest thermal resistance. By embedding a 4-loop pulsating heat pipe, the thermal resistance of the microchannel heat sink decreased by 21.27% compared to the basic design without a heat pipe.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Engineering, Manufacturing
Est Dev Patel, Subrata Kumar
Summary: The reliability and speed of modern electronic systems depend heavily on heat management methods. Pulsating heat pipes (PHPs), which utilize two-phase flow for passive cooling, have emerged as a preferred option for thermal management. The effects of construction parameters on the thermohydrodynamics of PHPs have been investigated through pressure, temperature measurement, and visualization experiments. The study highlights the significance of optimal filling ratio, low evacuation pressure, and high heat input for improved thermal performance.
IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY
(2022)
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
J. M. Pfotenhauer, X. Sun, A. Berryhill, C. B. Shoemaker
Summary: Pulsating heat pipes (PHPs) are being studied for thermal management in superconducting magnets and cryogenic space applications. The study shows that vertically dominated geometries perform better than horizontally dominated ones, with minimum thermal resistance values ranging from 1.5 K/W to 20 K/W for 1-meter-long PHPs. Results indicate that a fill ratio of 70% significantly reduces the influence of orientation and heat load on the PHP's thermal resistance.
APPLIED 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
Zhiguo Wang, Yuchen Fan, Yanyan Zhang, Zanxue Lai
Summary: This study introduces novel approaches for analyzing the heat transfer characteristics of graphene nanofluids in pulsating heat pipes. Nonlinear chaotic analysis methods are applied to ethanol-based graphene nanofluids with various concentrations. The investigation focuses on correlation dimensions and Kolmogorov entropy to provide numerical feedback on the nanofluid concentration. Additionally, reconstructed three-dimensional Singular Attractor phase diagrams offer morphological feedback on the working conditions of the pulsating heat pipe.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Jingru Zhan, Xi Chen, Yuzhe Ji, Pu Zheng, Wenhu Duan
Summary: This study investigates the effect of evaporator length on the thermal performance of ethane pulsating heat pipe (PHP). The experimental results show that extending the evaporator length can stabilize the evaporator temperature and reduce thermal resistance. The optimal evaporator length is found to be 120 mm, and the optimal working temperature is -40 degrees C.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
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
Thermodynamics
Tingsen Chen, Shuli Liu, Yongliang Shen, Binxu Gao, Abdur Rehman Mazhar
Summary: A novel triangular pulsating heat pipe (TPHP) is proposed to solve the starting-up issue in a non-vertical direction. The study investigates the impact of TPHP model structure, heating temperature, and liquid filling ratio on heat transfer performance. The results reveal that a rationalized model structure reduces heat flow resistance by up to 38.04%, and the optimum liquid filling ratio is around 50%. This study is critical for expanding the application of single-loop PHP in buildings.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Agnieszka Ochman, Wei-Qin Chen, Przemyslaw Blasiak, Michal Pomorski, Slawomir Pietrowicz
Summary: The article discusses the thermal-flow behaviors of a low-temperature Phase Change Material (PCM) used in Thermal Energy Storage (TES) applications, showing that the PCM can undergo phase change within a specific temperature range and has a high heat storage capacity. Comparison between numerical and experimental results indicates small errors during phase transitions.
Article
Energy & Fuels
Przemyslaw Blasiak, Marcin Opalski, Parthkumar Parmar, Cezary Czajkowski, Slawomir Pietrowicz
Summary: This article aims to numerically model a two-dimensional multiphase flow in a pulsating heat pipe using the volume of fluid method (VOF) within the open source software OpenFOAM. The influence of different mass transfer models on flow structures was analyzed and validated against experimental data.
Article
Thermodynamics
Przemyslaw Smakulski, Jun Ishimoto, Slawomir Pietrowicza
Summary: The qualitative mechanism of heat transfer during the cooling process by spraying Micro-Solid Nitrogen (MSN2) and the capability to vitrify a large-volume of samples are experimentally investigated. The results show higher heat flux values using MSN2 spray compared to boiling pool of Liquid Nitrogen (LN2) and the existence of a second local maximum of heat flux in the wall superheat temperatures. Vitrification of large-volume samples with higher cooling rates is achieved using a specific liquid solution.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Andrzej I. Nowak, Luca Pietrasanta, Cezary Czajkowski, Marco Marengo, Slawomir Pietrowicz
Summary: Passive two-phase heat transfer systems, such as pulsating heat pipes, have promising thermal management applications in the space sector. This research investigates the effect of inertia on flow patterns to improve modeling tools for pulsating heat pipes operating under reduced gravity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Energy & Fuels
Mikolaj Matuszczak, Slawomir Pietrowicz
Summary: Experimental analysis of free convection heating transfer in a flat wavy-fin heat exchanger shows that adding a chimney significantly improves the thermal performance.
Article
Thermodynamics
Adam Ruziewicz, Cezary Czajkowski, Andrzej I. Nowak, Jozef Rak, Norbert Zielinski, Stawomir Pietrowicz
Summary: This paper describes and investigates a novel patented system that shortens gas cylinder charging times and achieves self-sufficiency through the recovery of cold exergy. Numerical simulations and analysis based on energy and exergy are conducted to optimize the system and provide guidance for real installations.
Article
Energy & Fuels
Przemyslaw Blasiak, Piotr Kolasinski, Sindu Daniarta
Summary: This paper presents the results of numerical investigations on heat transfer in a multi-vane expander (MVE). MVEs have advantages such as low gas flow capacity and a low expansion ratio, making them interesting for various technological applications. However, there is a lack of in-depth analysis on the heat exchange mechanisms in these machines. The authors developed a numerical model and used ANSYS CFX for simulations, focusing on defining the expander heat transfer coefficients under various flow circumstances. The results revealed the heat transfer processes in MVEs and the changes in fluid velocity profile in the gap between the vane and the cylinder.
Article
Energy & Fuels
Marek Glogowski, Daniel Smykowski, Slawomir Pietrowicz
Summary: The effects of applying external electric fields on the coefficient of friction of a selected elastomer during mechanical interaction with steel and copper surface oil were investigated. The study considered two synthetic base oils, PAG 68 and PAO 6, and focused on a commonly used elastomer in rotary lip seals. The results showed that the external electric field significantly influenced the friction coefficient, with a decrease of about 30% observed when an external DC electric field was applied.
Review
Energy & Fuels
Daria Krasota, Przemyslaw Blasiak, Piotr Kolasinski
Summary: This article summarizes the knowledge on frost formation on heat exchanger surfaces, with a focus on the evaporator of domestic refrigerators. It provides an overview of different types of domestic refrigerators and evaporators, revisits common methods for testing frost formation, and presents the analysis of recent mathematical and CFD models.
Article
Thermodynamics
Cezary Czajkowski, Andrzej I. Nowak, Agnieszka Ochman, Slawomir Pietrowicz
Summary: The performance of an innovative thermal device based on Pulsating Heat Pipes (PHP) in a rotating system is studied and analyzed in this paper. The experimental research focuses on the influence of rotational speed, heat input, and filling ratio on the thermal performance. The results show that a low boiling point liquid can be used as a working fluid in a rotating system, and the thermal resistance of the process is higher compared to water.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Hai Zhao, Puzhen Gao, Xiaochang Li, Ruifeng Tian, Hongyang Wei, Sichao Tan
Summary: This study numerically investigates the interaction between flow-induced vibration and forced convection heat transfer in a tube bundle. The results show that the impact of flow-induced vibration on heat transfer varies in different flow velocity regions.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Rohit Chintala, Jon Winkler, Sugirdhalakshmi Ramaraj, Xin Jin
Summary: The current state of fault detection and diagnosis for residential air-conditioning systems is expensive and not suitable for widespread implementation. This paper proposes a cost-effective solution by introducing an automated fault detection algorithm as a screening step before more expensive tests can be conducted. The algorithm uses home thermostats and local weather information to identify thermodynamic parameters and detect high-impact air-conditioning faults.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
A. Azimi, N. Basiri, M. Eslami
Summary: This paper presents a novel optimization algorithm for improving the water-film cooling system of photovoltaic panels, resulting in a significant increase in net energy generation.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Duc-Thuan Phung, Chin-Hsiang Cheng
Summary: In this study, a novel CFDMD model is used to analyze and investigate the behavior of thermal-lag engines (TLE). The study shows that the CFDMD model effectively captures the thermodynamic behavior of the working gas and the dynamic behavior of the engine mechanism. Additionally, the study explores the temporal evolution of engine speed and the influence of various parameters on shaft power and brake thermal efficiency. The research also reveals the existence of a thermal-lag phenomenon in TLE.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Haiying Yang, Yinjie Shen, Lin Li, Yichen Pan, Ping Yang
Summary: The purpose of this article is to find a measure to improve the interfacial thermal transfer of graphene/silicon heterojunction. Through molecular dynamics simulation, it is found that surface modification can significantly reduce the thermal resistance, thereby improving the thermal conductivity of the graphene/silicon interface.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Qiong Wu, Yancheng Wang, Haonan Zhou, Xingye Qiu, Deqing Mei
Summary: This article introduces a visible methanol steam reforming microreactor, which uses an optical crystal as an observation window and measures the reaction temperature in real-time using infrared thermography. The results show that under lower oxygen to carbon ratio conditions, the microreactor has a higher heating rate and a stable gradient in temperature distribution.
APPLIED THERMAL ENGINEERING
(2024)
Review
Thermodynamics
Giulia Manco, Umberto Tesio, Elisa Guelpa, Vittorio Verda
Summary: In the past decade, there has been a growing interest in studying energy systems for the combined management of power vectors. Most of the published works focus on finding the optimal design and operations of Multi Energy Systems (MES). However, for newcomers to this field, understanding how to achieve the desired optimization details while controlling computational expenses can be challenging and time-consuming. This paper presents a novel approach to analyzing the existing literature on MES, with the aim of guiding practical development of MES optimization. Through the discussion of six case studies, the authors provide a mathematical formulation as a reference for building the model and emphasize the impact of different aspects on the problem nature and solver selection. In addition, the paper also discusses the different approaches used in the literature for incorporating thermal networks and storage in the optimization of multi-energy systems.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xuepeng Yuan, Caiman Yan, Yunxian Huang, Yong Tang, Shiwei Zhang, Gong Chen
Summary: In this study, a multi-scale microgroove wick (MSMGW) was developed by laser irradiation, which demonstrated superior capillary performance. The surface morphology and performance of the wick were affected by laser scan pitch, laser power, repetition frequency, and scanning speed. The MSMGW showed optimal capillary performance in alumina material and DI water as the working fluid.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Maofei Mei, Feng Hu, Chong Han
Summary: This paper proposes an effective local search method based on detection of droplet boundaries for understanding the dynamic process of droplet growth during dropwise condensation. The method is validated by comparing with experimental data. The present simulation provides an effective approach to more accurately predict the nucleation site density in future studies.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Rahul Kumar Sharma, Ashish Kumar, Dibakar Rakshit
Summary: The study explores the use of phase change materials (PCM) as a retrofit with Heating Ventilation and Air-conditioning systems (HVAC) to reduce energy consumption and improve air quality. By incorporating PCM with specific thickness and fin configurations, significant energy savings can be achieved in comparison to standard HVAC systems utilizing R134a. This research provides policymakers with energy-efficient and sustainable solutions for HVAC systems to combat climate change.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Zhenhua Ren, Xiangjin Meng, Xingang Qi, Hui Jin, Yunan Chen, Bin Chen, Liejin Guo
Summary: This paper investigates the heat transfer mechanism and factors influencing thermal radiation in the process of supercritical water gasification (SCWG) of coal, and proposes a comprehensive numerical model to simulate the process. Experimental validation results show that thermal radiation accounts for a significant proportion of the total heat exchange in the reactor and a large amount of radiant energy exists in the important spectral range of supercritical water. Enhancing radiative heat transfer can effectively increase the temperature of the reaction medium and the gasification rate.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Mauro Abela, Mauro Mameli, Sauro Filippeschi, Brent S. Taft
Summary: Pulsating Heat Pipes (PHP) are passive two-phase heat transfer devices with a simple structure and high heat transfer capabilities. The actual unpredictability of their dynamic behavior during startup and thermal crisis hinders their large-scale application. An experimental apparatus is designed to investigate these phenomena systematically. The results show that increasing the number of evaporator sections and condenser temperature improves the performance of PHP. The condenser temperature also affects the initial liquid phase distribution and startup time.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Ke Gan, Ruilian Li, Yi Zheng, Hui Xu, Ying Gao, Jiajie Qian, Ziming Wei, Bin Kong, Hong Zhang
Summary: A 3-dimensional enhanced heat pipe radiator has been developed to improve heat dissipation and temperature uniformity in cooling high-power electronic components. Experimental results show that the radiator has superior heat transfer performance compared to a conventional aluminum fin radiator under different heating powers and wind speed conditions.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xinyi Zhang, Shuzhong Wang, Daihui Jiang, Zhiqiang Wu
Summary: This study focuses on recovering waste heat from blast furnace slag using dry centrifugal pelletizing technology. A comprehensive two-dimensional model was developed to analyze heat transfer dynamics and investigate factors influencing heat exchange efficiency. The findings have important implications for optimizing waste heat recovery and ensuring safe operations.
APPLIED THERMAL ENGINEERING
(2024)
Article
Thermodynamics
Xincheng Wu, An Zou, Qiang Zhang, Zhaoguang Wang
Summary: The boosting heat generation rate of high-performance processors is challenging traditional cooling techniques. This study proposes a combined design of active jet intermittency and passive surface modification to enhance heat transfer.
APPLIED THERMAL ENGINEERING
(2024)
