Article
Polymer Science
Peter Rantuch, Jozef Martinka, Ales Haz
Summary: This study focused on the energy potential and combustion process of torrefied wood from five different types of wood. It found that increasing external heat flux decreased the evenness of combustion but improved combustion efficiency. The results are valuable for both energy production and fire safety risk assessment of stored torrefied wood.
Article
Energy & Fuels
Yu Wang, Jianfeng Pan, Junfeng Wang, Qingbo Lu, Yi Zhang, Evans K. Quaye
Summary: The FREI dynamics of methane/oxygen mixture were experimentally observed in a micro quartz tube combustor. A 2-D model successfully predicted the propagation features of the FREI flame, which were in agreement with the experimental results. Four stages of flame front propagation were revealed based on simulations: accelerating stage, decelerating stage, reverse propagating stage, and weak reaction stage. Further analysis on radical and heat release rate (HRR) confirmed that the regeneration of CH4 behind the flame front and the reducing consumption of the overall amount of methane were the main factors for flame deacceleration and eventually extinction. After extinction, methane consumption tended to occur along the combustor wall due to the high wall temperature.
Article
Polymer Science
Qiang Xu, Lin Jiang, Andrea Majlingova, Nikoleta Ulbrikova, Rhoda Afriyie Mensah, Oisik Das, Filippo Berto
Summary: This study examines the feasibility of using a micro combustion calorimeter to analyze the calorimetry kinetics of wood. Two measurement methods, Method A and Method B, were employed to evaluate the combustion characteristics of different wood samples. The results obtained from the two methods showed significant differences, indicating the potential of Method B in evaluating the combustion heat release of materials.
Article
Energy & Fuels
Ruslan Khamedov, Wonsik Song, Francisco E. Hernandez-Perez, Hong G. Im
Summary: Ammonia combustion is a promising energy source with zero CO2 emissions and potential use in hydrogen combustion. The study provides insights into the heat release characteristics of ammonia in MILD combustion through numerical simulations. The findings have important implications for understanding the combustion behavior and reaction mechanisms of ammonia.
Article
Engineering, Multidisciplinary
Yi Zhong, Tianhong Zhang, Yan Zhang, Tao Cheng
Summary: This paper presents the development of a flame temperature and HRR sensor based on radical emission spectroscopy, which can accurately and real-time measure the flame temperature and heat release rate. It is of great significance for active control of combustion instability.
Article
Thermodynamics
Yan Huo, Ya-Ping Yu, Dong-mei Yang, Gao-Wan Zou, Hui Dong
Summary: Special flame merging behavior and complex combustion characteristics can be formed when multiple pool fires are subjected to tangential flow and heat transfer in a shaft. In this study, quadruple pool fires evolutionary experiments were conducted in a shaft to analyze the influence of pooled spacing and side slit width on flame merging behavior. The primary influencing mechanism of merged flame evolution was explained based on heat transfer and thermal feedback between fire sources.
HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Tong Xu, Peng Lei
Summary: This paper experimentally studied the temperature profile and flame height variation of a diesel-wetted wood powder fire. The study found that the combustion process can be divided into three stages and that the heat release rate of this kind of fire is lower than that of a pool fire with the same burner size. The flame height also decreases as the fuel feed rate decreases.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Engineering, Industrial
Pascale Vacca, Eulalia Planas, Christian Mata, Juan Antonio Munoz, Frederic Heymes, Elsa Pastor
Summary: The combustion of artificial fuels at Wildland-Urban Interface (WUI) homeowner scale is a significant contributor to fire spread through a property, posing major safety issues at the community level. Real-scale burning tests were conducted to gather quantitative data on these fuels and evaluate vulnerabilities of WUI properties through Performance-Based Design methodologies, with results indicating that certain fuel packs are more hazardous than others.
Article
Chemistry, Physical
Chengbin Song, Haiou Wang, Mengzhen Cheng, Tingquan Tian, Kun Luo, Jianren Fan
Summary: This study investigates the combustion characteristics of ammonia and develops surrogate models for predicting the heat release rate (HRR). The NH2+NO elementary reaction is found to be an important contributor to HRR, and the [NH2][NO] surrogate is proposed as a promising predictor. The findings have significant implications for understanding ammonia combustion and its practical applications.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Physical
Qiang An, Sina Kheirkhah, Jeffrey Bergthorson, Sean Yun, Jeongjae Hwang, Won June Lee, Min Kuk Kim, Ju Hyeong Cho, Han Seok Kim, Patrizio Vena
Summary: Flame shapes and transitions of premixed hydrogen enriched methane flames in a 3D-printed low-swirl burner were studied. Three different flame shapes were observed, each stabilized by different mechanisms such as flame-flow velocity balance, inner shear layer, large-scale eddies in the outer shear layer, and burner hardware anchorage. The transitions between flame shapes were mainly influenced by hydrogen fraction and bulk velocity, with the W-to-crown transition attributed to the upstream propagation and attachment of the flame outer edges.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Kaushik Nonavinakere Vinod, Tiegang Fang
Summary: Ammonia is being considered as an alternative to fossil fuel in gas turbine and internal combustion engines due to its carbon-free and hydrogen energy-carrying nature. However, there are barriers such as long ignition delay, slow flame speed, and low reactivity that need to be overcome before its practical applications. This study explores the use of oxygen-enriched combustion to improve the ignition of ammonia and investigates its combustion characteristics in a constant volume combustion chamber.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Kin-Pang Cheong, Guochang Wang, Jicang Si, Jianchun Mi
Summary: This study presents a new criterion for identifying the occurrence of nonpremixed MILD combustion using local heat release rate (HRR) based on experimental observations, flow analysis, and chemical calculations. Unlike CH4, the nonpremixed MILD combustion of C3H8 exhibits a negative HRR region due to complex pyrolysis, which is distinct from the conventional flame.
Article
Thermodynamics
Shuai Yan, Yan Gong, Zhengqiao Duan, Qinghua Guo, Guangsuo Yu
Summary: The correlation between heat release rate and OH*, CH* chemiluminescence in methane inverse diffusion flame is explored. It is found that the flame heat release rate is mainly related to the formation and consumption of several species. The gradient of ground state OH concentration and the distribution of CH* and OH* are consistent with the heat release rate distribution.
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
Energy & Fuels
Yi Luo, Yituan He, Chunzhi Liu, Shiyong Liao
Summary: The effects of adding dimethyl ether (DME) on biodiesel (BD) combustion were studied through counterflow flame modeling. The study found that both air-side and fuel-side blending of DME can slightly increase the peak temperature and widen the reaction zones of the flames. DME is primarily oxidized within a specific flame region with a higher temperature than BD.
