Article
Engineering, Environmental
Zhenhua Wang, Kuibin Zhou, Le Zhang, Xuan Nie, Yueqiong Wu, Juncheng Jiang, Anne Simone Dederichs, Lu He
Summary: The study investigated the impact of impinging jet fire on vertical plates, revealing the effects of nozzle exit velocity, exit diameter, and exit-plate spacing. Experimental observations showed changes in flame pattern and color with variations in exit velocity and exit-plate spacing. A new correlation was developed to predict the flame extension area of horizontally and vertically impinging jet fires.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Engineering, Chemical
Zhenhua Tang, Zhirong Wang, Kun Zhao
Summary: This study investigates the burning behavior of inclined jet flames under the influence of a vertical water curtain by conducting a series of experiments. The results show that an increase in fuel flow rates or nozzle diameter leads to a larger flame extension length. With the increase of flame inclination angle, the flame extension length decreases and the influence of nozzle diameter on the flame extension length is attenuated. A mathematical model is proposed to predict the flame extension length of jet flames with different diameters, fuel flows, and inclinations under the influence of a water curtain, and it is validated by previous research data.
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
(2023)
Article
Thermodynamics
Jinfei Zhao, Jiahao Liu, Haihang Li, Jian Wang
Summary: Experimental investigation on horizontal buoyancy-controlled jet fires was conducted to study the flame projection length under different ambient air pressures. It was found that the flame projection length increases with an increase in heat release rate and decreases with increasing ambient air pressure. The relationship between flame projection length and atmospheric pressure can be expressed as a power law.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Jinfei Zhao, Jiahao Liu, Chao Ding, Xuehui Wang, Jiang Wang
Summary: Ethylene, an important raw material in the petrochemical industry, is widely used in the production of polyethylene and vinyl chloride. In this study, experiments were conducted on inclined ethylene jet fires to investigate their horizontal extension distances. The results showed that the horizontal extension distance of ethylene jet fires increases with the heat release rate but decreases with the inclined angle. Through similarity analysis, a correlation was established between the dimensionless horizontal extension distance (Lph/d) and the flame Froude number (Frf). Additionally, a correlation was derived between the dimensionless horizontal extension distance and the modified flame Froude number Frf*(Frf* = cos theta 3/4. Frf), which can accurately predict the experimental data.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Ping Huang, Shengtao Liu, Chunxiang Liu, Fuqiang Yang, Baihan Zhang, Longxing Yu
Summary: The double slope roof is widely used in buildings due to its good drainage and stable structure, but fire accidents are common. This study investigated the flame extension lengths beneath a double slope roof induced by gaseous fuel jet flame. Results showed that the length of flame extension was longer in the ridge direction compared to the slope direction. A new correlation incorporating the effect of the roof angle was established to estimate the equivalent heat release rate at the ceiling, which was validated by experimental data.
Article
Energy & Fuels
Jinpeng Hua, Jianfeng Pan, Feiyang Li, Baowei Fan, Zhongjia Li, Abiodun Oluwaleke Ojo
Summary: This study experimentally and numerically investigated the heat transfer characteristics of a premixed methane-air flame jet impinging on a hemispherical surface. The effects of mixture equivalence ratio, burner to plate distance, mixture Reynolds number, and curvature ratio on heat transfer characteristics were studied. CFD simulations were performed to analyze the heat flux distribution and average heat flux on the impingement surface. Heat transfer efficiency was used to evaluate the thermal performance of the impinging flame jet. The results showed that equivalence ratio had a significant effect on flame height, which influenced heat transfer efficiency. The burner-to-plate distance played a decisive role in heat transfer characteristics, and the best thermal performance was achieved when the flame premixed cone just touched the impingement surface.
Article
Energy & Fuels
Zhenhua Tang, Kun Zhao, Zhirong Wang, Jizhe Wang, Yi Pan
Summary: This study focuses on the burning behaviors of horizontal hydrogen jet fires under the action of a water curtain system. The experimental results show that the shape of the hydrogen jet flame expanded on the water curtain is elliptical at different conditions. A new dimensionless heat release rate is proposed to estimate the flame extension length.
Article
Thermodynamics
L. L. Dong, C. S. Cheung, C. W. Leung
Summary: The study explores the feasibility of using a swirling inverse diffusion flame jet for impingement heating and finds that the level of air swirling significantly affects the heat transfer rate, with appropriate air swirling levels leading to heat transfer enhancement.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Thermodynamics
Qiang Wang, Aquan Lu, Le Chang, Ben Wang
Summary: This study experimentally investigates the trajectory lengths of flames with different upward inclined angles, taking into account the effect of crosswind. The results show that the flame trajectory length increases with increasing inclined angle at low crosswind speeds, but decreases as the crosswind speed increases. Correlation models are developed to predict the flame horizontal length and vertical heights, and a mathematical analysis model based on circular approximation is established to predict the flame trajectory length of inclined buoyant jet fire in crosswind.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Thermodynamics
Ritesh Kumar Parida, Anil R. Kadam, Madav Vasudeva, Vijaykumar Hindasageri
Summary: This paper aims to estimate two unknown parameters - Nusselt number and effectiveness - analytically and study the heat transfer characteristics of impinging flame jet over a wedge-shaped structure. The observations concerning heat transfer characteristics of the impinging flame jet are discussed, and the flame jet's heating effect has been observed to improve as the wedge angle is increased from 90 degrees to 120 degrees. The uncertainty of the estimated parameters is evaluated using the Monte Carlo technique.
APPLIED THERMAL ENGINEERING
(2021)
Article
Chemistry, Physical
Zhirong Wang, Kewei Jiang, Kun Zhao, Pinkun Guo
Summary: This study experimentally investigated the effects of nozzle inclined angle, diameter, and heat release rate on the characteristics of syngas jet flame. A unified empirical model was established to estimate the horizontal extension length of the syngas jet flame for nozzles with different diameters and inclined angles.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Mechanics
A. Colombie, E. Laroche, F. Chedevergne, R. Manceau, F. Duchaine, L. Gicquel
Summary: This study uses large-eddy simulation to evaluate the Reynolds-stress budgets of a round impinging jet, focusing on the stagnation region where pressure terms dominate the budgets and balance the Reynolds-stress production and convective fluxes. The study highlights the role of pressure diffusion term in conveying energy to the wall and explains the failure of turbulence models due to inadequate modeling of this term.
Article
Thermodynamics
Kristian Ronnberg, Christophe Duwig
Summary: In this study, heat transfer arising from an impinging jet at a Reynolds number of 5000 was investigated through Large Eddy Simulation (LES). The heat transfer was found to be distributed according to a gamma distribution, and was decomposed using proper orthogonal decomposition (POD) and extended proper orthogonal decomposition (EPOD). The results showed that distinct flow features were associated with low order heat transfer modes, with dominant modes identified as ring-like vortex structures. Reconstruction of the heat transfer field revealed radially outward moving structures with a phase velocity of 0.23 U-b.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Takuma Koizumi, Takuma Kogawa, Juan F. Torres, Yuki Kanda, Atsuki Komiya
Summary: This study investigates the impact of a jet on a natural convection boundary layer, which can produce periodically alternating T and L flows and enhance heat transfer. Based on frequency analysis, the instability waves downstream of the heated wall are classified into resonance, convective instability, and turbulence. The study also demonstrates that an appropriate choice of jet temperature and velocity can control the instability waves over the natural convection boundary layer.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Adnan Rasheed, Usman Allauddin, Hafiz Muhammad Ali, Muhammad Uzair, Patrick G. Verdin, Yasir H. Siddiqui
Summary: This research focuses on the heat transfer of a single jet flow over a heated surface with detached ribs. A computational study is conducted to examine the effects of the ribs. Different dimensions of a rectangular rib design are studied to understand their impact on heat transfer at various nozzle positions.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Energy & Fuels
Xu Fang, Xiaolei Zhang, Richard K. K. Yuen, Longhua Hu
Summary: This study provides an experimental investigation and scaling analysis of diffusion flame side sag behavior, finding that the evolution of flame side sag can be clearly distinguished as four phases, with turning points related to crosswind speed, burner size, and heat release rate. The transition of four phases can also be quantified based on characteristic length scales derived from general dimensionless functions correlating experimental results of upstream and downstream flame side sag lengths.
Article
Energy & Fuels
Jiang Lv, Xiaolei Zhang, Shixiang Liu, Hongyu Lu, Yuxuan Ma, Longhua Hu
Summary: This study investigates the flame morphology of horizontal turbulent jets under different sub-atmospheric pressures, showing that the flame horizontal projection length increases with the heat release rate, while the flame vertical height exhibits a non-monotonic behavior. By using non-dimensional formulas and characteristic length scale, the flame characteristics under various sub-atmospheric pressures are described accurately. The developed integral model takes into account air entrainment mechanism, top hat profiles, and strong plume theory, providing a good representation of the flame morphologic characteristics.
Article
Energy & Fuels
Hanyu Xiong, Xiaolei Zhang, Yanli Miao, Longhua Hu
Summary: This study investigates the flame spread behavior and flammability of heterogeneous fuels involving polystyrene and corrugated cardboard. Experimental results show a five-stage combustion process with a new method proposed to estimate the combustion area on internal surface. By calculating the B numbers, it is found that the flammability of the heterogeneous fuels is increased compared to single components.
Article
Engineering, Environmental
Shixiang Liu, Xiaolei Zhang, Xu Fang, Longhua Hu
Summary: This study investigates the combustion behaviors and instability characteristics of dual jet flames under cross wind, utilizing propane fire sources with different nozzle diameters and separation distances. The results show that the rear jet flame has a smaller tilt angle and lower blow-out cross wind velocity compared to the front jet flame, due to the interference from the front jet flame. The combustion of the front jet flame also has a restrictive effect on the rear jet flame.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2022)
Article
Thermodynamics
Siyao Jia, Longhua Hu, Yuxuan Ma, Xiaolei Zhang, Osamu Fujita
Summary: This study investigates the downward flame spread and extinction over inclined electrical wire under horizontal wind. The results show a non-monotonic trend of flame spread rate with increasing horizontal wind velocity, identifying four different regimes based on heat transfer mechanisms. The flame spread rate of Cu-core wire and NiCr-core wire exhibit different dependencies on inclination angle, showcasing enhanced quenching effect and weakened blow-off effect with increased inclination angle.
COMBUSTION AND FLAME
(2022)
Article
Energy & Fuels
Yuhang Chen, Xiaolei Zhang, Yanli Miao, Longhua Hu
Summary: This paper experimentally studies the thermal characteristic and flame behavior of dual tandem pool fires in cross airflow. The results show that the flames tend to merge more easily in cross airflow with larger heat release rates of the upstream flame. The maximum temperature in the flame region increases with the increasing cross airflow velocity, and the flame height and flame horizontal projection length are also affected by the separation distance.
Article
Thermodynamics
Xiaolei Zhang, Longhua Hu, Xiaochun Zhang, Xiepeng Sun, Guillermo Rein
Summary: This paper investigates the temperature profiles in ceiling jet induced by a finite line-source fire plume impinging upon an unconfined ceiling. The experimental results show that the temperature profile is two-dimensional and decays differently in different directions. A new equation is derived to describe the temperature profile based on the characteristic length scales. This study provides important data and a new equation for understanding the ceiling jet temperature distributions induced by finite line-sources in building fire science.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Yanli Miao, Yuhang Chen, Fei Tang, Xiaolei Zhang, Longhua Hu
Summary: An experimental study was conducted to simulate the downhill spread of a line-source fire over an inclined surface. The study investigated the flame geometry and thermal radiation to the surroundings and the inclined surface. The results showed that the flame height decreased and the flame length along the inclined surface increased with an increased inclination angle.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Yuhang Chen, Kazui Fukumoto, Xiaolei Zhang, Yujie Lin, Fei Tang, Longhua Hu
Summary: This study experimentally investigates the flame horizontal lengths of elevated and ground pool fires in cross airflows, and compares them. The quantification of this fundamental problem, which considers the air entrainment and combustion structure change due to the ground's Coanda effect at the leeward side, is of practical significance.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Xiaolei Zhang, Yong Yang, Xiepeng Sun, Fei Ren, Xiang Fang, Longhua Hu
Summary: This paper investigates the behavior of facade flames ejected from a top-hung window, and establishes models to describe the characteristics of flame ejection, flame height, and flame depth based on the window's dimensions and opening angle. The study provides valuable data and models for assessing the risk and impact of fires involving top-hung windows on urban environments.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Xu Fang, Xiaolei Zhang, Longhua Hu
Summary: This study investigated the projected vertical flame height of buoyant turbulent horizontally-oriented rectangular-source jet fires through experiments. The results show that the flame height initially increases and then decreases with the aspect ratio of the burner, as well as with the heat release rate. A critical dimensionless heat release rate was identified for the transition behavior. The findings provide new insights into the transitional behavior of vertical flame height in rectangular-source jet fires. Rating: 7 out of 10.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Yuxuan Ma, Longhua Hu, Yajun Huang, Fukai Chu, Xiaolei Zhang, Zhengda Guo, Siyao Jia, Nan Zhu, Yuhang Chen, Yan Gu
Summary: This paper presents an experimental investigation on concurrent flame spread over composites with flame retardants and external radiation factors. The findings indicate that the flame spread rate, flame preheat length, and flame height of composites with flame retardants may be larger than those without, under high external radiation. The theoretical analysis and experimental results support the conclusion that the thermal conductivity of the fuel-gas mixture and the temperature dependency of molecular diffusivity play significant roles in the heat/mass transfer mechanism of flame spread.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Xiang Fang, Xiepeng Sun, Xiaolei Zhang, Fei Ren, Yong Yang, Longhua Hu
Summary: This article presents an experimental and CFD simulation investigation on temperature evolution and flame behavior in a compartment with a ceiling vent under ambient wind. The study reveals two types of fire behavior regimes inside the compartment for small or large vents. With a small vent, the flame is located at the center and extinguishes due to lack of oxygen. With a large vent, there is a flame transition from windward to leeward accompanied by the transition of temperature distribution.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Construction & Building Technology
Xiaotao Chen, Xiepeng Sun, Xiaolei Zhang, Fei Ren
Summary: Corridor-compartment fire is a crucial issue for evacuation and firefighting in underground spaces. However, limited studies have been conducted to quantify the temperature changes inside the compartment and the corridor ceiling flow induced by such fires with different compartment door sizes and corridor widths. In this study, a reduced-scale experimental model was used to measure and analyze the burning rate and temperature distribution. The results show that there is a non-dimensional correlation for the temperature rise inside the compartment under over-ventilated and under-ventilated conditions. The temperatures of the ceiling flow at the corner between the corridor wall and ceiling increase slowly before reaching under-ventilated condition and decrease significantly with increasing corridor width. A non-dimensional model considering the effect of corridor width is proposed to predict the temperature in underground corridors and assess the fire thermal hazard.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2023)
Review
Thermodynamics
Yuhang Chen, Jun Fang, Xiaolei Zhang, Yanli Miao, Yujie Lin, Ran Tu, Longhua Hu
Summary: Pool fire is a diffusion combustion process above a horizontal fuel surface with low initial momentum. It has both scientific significance in classical diffusion combustion studies and practical importance in fire safety engineering.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2023)
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)
