Article
Chemistry, Physical
Yue Wang, Xin Zhang, Yanfei Li
Summary: This study presents a 3D modeling of methane-hydrogen-air turbulent premixed combustion using the turbulence constant volume combustion chamber (CVCC) as an experimental platform. The effects of turbulence intensity and hydrogen fraction on flame propagation process are analyzed. The results show that the flame propagation rate increases with the increase of turbulence intensity, and the maximum combustion pressure and maximum pressure rise rate also increase. The addition of hydrogen significantly enhances the flame propagation rate, and the maximum pressure is increased.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Review
Energy & Fuels
Abdulrahman Abdullah Bahashwan, Rosdiazli Bin Ibrahim, Madiah Binti Omar, Mochammad Faqih
Summary: Lean blowout (LBO) is a critical issue in lean premixed gas turbine combustion. Various prediction methods have been developed, including semi-empirical models, numerical simulations, hybrid models, experimental models, and data-driven models. Among them, data-driven models have shown higher accuracy and reproducibility, but further research is needed to improve prediction accuracy on different combustors.
Article
Engineering, Aerospace
Govindaraj Muthuselvan, Muralidhara Suryanarayana Rao, Venkat S. Iyengar, Manjunath Pulumathi, Sundararajan Thirumalachari, K. Srinivasan
Summary: The study found that an equivalence ratio of 0.79 in the primary combustion zone of a gas turbine combustor is optimal for high efficiency and low NOx emissions while maintaining flame stability. However, approaching the lean blowout limit can lead to intermittent low-frequency, high-amplitude pressure oscillations.
JOURNAL OF PROPULSION AND POWER
(2021)
Article
Thermodynamics
Somnath De, Sabyasachi Mondal, Arijit Bhattacharya, Sirshendu Mondal, Achintya Mukhopadhyay, Swarnendu Sen
Summary: This study focuses on the dynamics of swirl-stabilized premixed combustion near lower and higher flammability limits, and employs metrics from statistics and dynamical systems theory for analysis. It is observed that near the blowout limits, the flame dynamics exhibit low-frequency oscillations, leading to a gradual reduction in the mean frequency of the combustion system. Furthermore, the scaling property of flame oscillation, examined using the Hurst exponent, shows a decreasing trend as combustion approaches both LBO and RBO.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Mechanics
Y. Yalcinkaya, A. G. Gungor
Summary: This investigation examines the impact of axial pressure gradient on the dynamics of flame-vortex interaction in a lean premixed bluff body stabilized flame. The study utilizes large eddy simulations (LESs) of four different combustor geometries with varying pressure gradients. The results show that the pressure gradient significantly influences flame structure, emission characteristics, vortex dynamics, and flame stability. The findings suggest that adjusting the combustor geometry to create a favorable pressure gradient can enhance combustion performance and stability in lean premixed flames.
Article
Thermodynamics
Anthony J. Morales, Jonathan Reyes, Isaac Boxx, Kareem A. Ahmed
Summary: Experimental investigation shows that the lean blowout process of premixed bluff-body flames is influenced by turbulence intensity. As turbulence levels increase, the blowout mechanism becomes more dependent on flame-turbulence interactions rather than flame and shear layer interactions. High turbulence conditions lead to flame-eddy interactions augmenting flame stretching and ultimately resulting in blowout.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Paul Palies, Ragini Acharya
Summary: This article presents a flame-resolved transient simulation of the Cavaliere et al. premixed flame experiment to investigate mechanisms leading to lean blowoff. The computational results show good agreement with experimental data, and the underlying mechanism of lean blowout is analyzed using DMD technique, flow field visualizations, and OH field analysis. The key phenomenon leading to lean blowout in this configuration is associated with convective motion of cooler combustion products into the inner recirculation zone as equivalence ratio decreases.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Zhang Chen, Tianwei Yang, Shanshan Zhang, Shan Li, Zhuyin Ren
Summary: This study systematically investigates the efficient modeling of NOx and CO formation characteristics, demonstrating the successful application in a full-scale methane gas turbine combustor. The results show that the predicted NOx and CO emissions agree with experimental measurements, with discrepancies in NOx emission attributed to fuel/air unmixedness and the sensitivity of CO emission prediction to combustion/kinetics model parameters.
Article
Engineering, Aerospace
V. Kirubakaran, R. Naren Shankar
Summary: This study predicts the effect of combustor inlet area ratio on the lean blowout limit of a swirl stabilized can-type micro gas turbine combustor. The results show that the LBO equivalence ratio decreases with an increase in inlet velocity, but decreases significantly at low inlet velocities with a decrease in CIAR.
AIRCRAFT ENGINEERING AND AEROSPACE TECHNOLOGY
(2021)
Article
Energy & Fuels
Lei Li, Zhongguang Sun, Yongjiang Luo, Yunpei Liang, Xinyu Wang, Kequan Wang
Summary: With coal mine methane emissions becoming a global issue, optimizing the performance of porous burning systems has become crucial for reducing low-concentration gas emissions. Research shows that burners with alumina particles of different diameters are suitable for low-flow and high-flow lean-burn scenarios, respectively.
Article
Chemistry, Physical
Sungwoo Park
Summary: The study investigates the effects of hydrogen addition to methane in lean-premixed laminar flames at elevated pressures. It demonstrates that hydrogen addition leads to an increase in NO concentration in premixed flames due to higher flame temperature, while N₂O mechanism plays an important role in NO formation. The findings provide insights into the mechanisms of NO formation in lean flames and the impact of hydrogen addition.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Ali Edalati-nejad, Sayyed Aboozar Fanaee, Maryam Ghodrat, Javad Khadem
Summary: This study conducted an unsteady analysis of methane/air premixed counterflow flame under different flame conditions and stability parameters, yielding insights into factors affecting flame stability and structure such as hydraulic distance of microchannel, time-dependent characteristics, and the impact of time variations. The results presented show the importance of considering time-dependent analysis to understand flame behavior before reaching a steady-state condition.
JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Thermodynamics
Takashi Ohta, Yuta Onishi, Yasuyuki Sakai
Summary: This study investigated the mechanism of modulation of turbulent structures near a combustion engine wall through direct numerical simulations. The results showed that flame propagation influenced the turbulence and suppressed the turbulence vortices along the wall. Additionally, the study found that the vortex structure had a significant impact on the heat release rate distribution and concentration distribution of the chemical species.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
T. Capurso, D. Laera, E. Riber, B. Cuenot
Summary: Today's climate and energy challenges are driving the use of decarbonised and renewable alternative fuels, such as hydrogen, in power generation and transportation. This study proposes high-fidelity Large Eddy Simulations (LES) with detailed NOx analyzes to assess the production of NOx in a hydrogen flame. A novel kinetic scheme is developed to accurately predict the complex transport phenomena and NO dynamic formation in lean turbulent hydrogen flames. The study provides valuable insights for understanding and controlling NOx emissions from hydrogen combustion.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Benjamin Peters, Nicholas Rock, Ben Emerson, Nagi Gebraeel, Kamran Paynabar
Summary: This paper introduces a method for monitoring aircraft engine flame-out through data analytics, including data curation, fault detection, and adaptive alarm reliability assessment. Alarms are used as precursors of impending flame-out, updated in an adaptive manner based on information from previous occurrences and currently observed signals, providing a probabilistic means to assess the proximity of flame-out.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Saad Akhtar, Jundika C. Kurnia, Tariq Shamim
Article
Thermodynamics
Minghan Xu, Saad Akhtar, Ahmad F. Zueter, Victor Auger, Mahmoud A. Alzoubi, Agus P. Sasmito
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2020)
Article
Thermodynamics
Saad Akhtar, Minghan Xu, Agus P. Sasmito
Summary: A novel semi-analytical framework is presented for predicting the freezing process of droplets, accurately modeling each stage. This framework combines heat conduction equations with a nucleation model to compute supercooling degree, providing insights into freezing dynamics. Validation of the model against experimental and numerical data shows it to be accurate and efficient for predicting crystal growth and freeze simulations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Multidisciplinary
Saad Akhtar, Minghan Xu, Agus P. Sasmito
Summary: This study introduces a novel crystal growth model to investigate the dynamics of recalescence during droplet freezing. By developing a statistical framework and optimizing parameters, it can accurately simulate the interface kinetics of supercooled water. Key findings demonstrate that the dendritic growth rate is influenced by diffusivity and interface kinetics factor.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Thermodynamics
Saad Akhtar, Minghan Xu, Agus P. Sasmito
Summary: Droplet solidification is commonly treated as a single-phase problem in literature, but this approach fails to accurately capture the initial temperature and freezing time. This study presents a singular perturbation solution for the two-phase Stefan problem in a finite spherical domain under low Stefan number and arbitrary Biot number limits. The asymptotic solution developed for droplets at non-freezing initial temperatures with convective boundary conditions is validated with experimental results and numerical models.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Mathematics, Applied
Minghan Xu, Saad Akhtar, Ahmad F. Zueter, Mahmoud A. Alzoubi, Laxmi Sushama, Agus P. Sasmito
Summary: This paper presents an asymptotic analysis of a two-phase Stefan problem in cylindrical coordinates, comparing it with numerical iteration methods like the enthalpy method and revealing the role of mushy-zone thickness. The study shows that the asymptotic solution is capable of tracking interface motion and evaluating temperature distribution in PCMs, with a much lower computational cost compared to other numerical schemes.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Construction & Building Technology
Jayaveera Muthusamy, Syed Haq, Saad Akhtar, Mahmoud A. Alzoubi, Tariq Shamim, Jorge Alvarado
Summary: The study shows that contamination range is slightly lower for females due to lower cough velocities and particle counts. Wearing a cloth mask reduces contamination range by approximately two-thirds compared to coughing without a mask, however, aerosolized particles can reach longer distances and drift for extended periods of time.
BUILDING AND ENVIRONMENT
(2021)
Article
Thermodynamics
Minghan Xu, Yuguo Gao, Fu Fang, Saad Akhtar, Benitta A. Chaedir, Agus P. Sasmito
Summary: In this study, we address the thermal interference and time evolution prediction of phase change materials (PCM) in the field of cold thermal energy storage (CTES). By establishing an experimental system and developing a mathematical model, we obtain accurate experimental and simulation results.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mining & Mineral Processing
Lu Yueze, Akhtar Saad, Sasmito P. Agus, Kurnia C. Jundika
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2017)
Article
Construction & Building Technology
Saad Akhtar, Mustafa Kumral, Agus P. Sasmito
BUILDING AND ENVIRONMENT
(2017)
Article
Energy & Fuels
Saad Akhtar, Mohammed N. Khan, Jundika C. Kurnia, Tariq Shamim
Proceedings Paper
Energy & Fuels
Mahmoud A. Alzoubi, Saad Akhtar, Matthew Fong, Agus P. Sasmito
PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY
(2017)
Proceedings Paper
Mining & Mineral Processing
Yueze Lu, Saad Akhtar, Agus P. Sasmito, Jundika C. Kurnia
OPERATIONAL AND ENVIRONMENTAL MINE HEALTH AND SAFETY PRACTICE AND INNOVATION
(2016)
Review
Energy & Fuels
Jundika C. Kurnia, Sachin V. Jangam, Saad Akhtar, Agus P. Sasmito, Arun S. Mujumdar
BIOFUEL RESEARCH JOURNAL-BRJ
(2016)
Article
Energy & Fuels
Shitong Fang, Houfan Du, Tao Yan, Keyu Chen, Zhiyuan Li, Xiaoqing Ma, Zhihui Lai, Shengxi Zhou
Summary: This paper proposes a new type of nonlinear VIV energy harvester (ANVEH) that compensates for the decrease in peak energy output at low wind speeds by introducing an auxiliary structure. Theoretical and experimental results show that ANVEH performs better than traditional nonlinear VIV energy harvesters under various system parameter variations.
Article
Energy & Fuels
Wei Jiang, Shuo Zhang, Teng Wang, Yufei Zhang, Aimin Sha, Jingjing Xiao, Dongdong Yuan
Summary: A standardized method was developed to evaluate the availability of solar energy resources in road areas, which combined the Analytic Hierarchy Process (AHP) and the Geographic Information System (GIS). By analyzing critical factors and using a multi-indicator evaluation method, the method accurately evaluated the utilization of solar energy resources and guided the optimal location selection for road photovoltaic (PV) projects. The results provided guidance for the application of road PV projects and site selection for route corridors worldwide, promoting the integration of transportation and energy.
Article
Energy & Fuels
Chang Liu, Jacob A. Wrubel, Elliot Padgett, Guido Bender
Summary: The study investigates the effects of coating defects on the performance of the anode porous transport layer (PTL) in water electrolyzers. The results show that an increasing fraction of uncoated regions on the PTL leads to decreased cell performance, with continuous uncoated regions having a more severe impact compared to multiple thin uncoated strips.
Article
Energy & Fuels
Marcos Tostado-Veliz, Xiaolong Jin, Rohit Bhakar, Francisco Jurado
Summary: In this paper, a coordinated charging price mechanism for clusters of parking lots is proposed. The research shows that enabling vehicle-to-grid characteristics can bring significant economic benefits for users and the cluster coordinator, and vehicle-to-grid impacts noticeably on the risk-averse character of the uncertainty-aware strategies. The developed pricing mechanism can reduce the cost for users, avoiding to directly translate the energy cost to charging points.
Article
Energy & Fuels
Duan Kang
Summary: Building an energy superpower is a key strategy for China and a long-term goal for other countries. This study proposes an evaluation system and index for measuring energy superpower, and finds that China has significantly improved its ranking over the past 21 years, surpassing other countries.
Article
Energy & Fuels
Fucheng Deng, Yifei Wang, Xiaosen Li, Gang Li, Yi Wang, Bin Huang
Summary: This study investigated the synergistic blockage mechanism of sand and hydrate in gravel filling layer and the evolution of permeability in the layer. Experimental models and modified permeability models were established to analyze the effects of sand particles and hydrate formation on permeability. The study provided valuable insights for the safe and efficient exploitation of hydrate reservoirs.
Article
Energy & Fuels
Hao Wang, Xiwen Chen, Natan Vital, Edward Duffy, Abolfazl Razi
Summary: This study proposes a HVAC energy optimization model based on deep reinforcement learning algorithm. It achieves 37% energy savings and ensures thermal comfort for open office buildings. The model has a low complexity, uses a few controllable factors, and has a short training time with good generalizability.
Article
Energy & Fuels
Moyue Cong, Yongzhuo Gao, Weidong Wang, Long He, Xiwang Mao, Yi Long, Wei Dong
Summary: This study introduces a multi-strategy ultra-wideband energy harvesting device that achieves high power output without the need for external power input. By utilizing asymmetry, stagger array, magnetic coupling, and nonlinearity strategies, the device maintains a stable output voltage and high power density output at non-resonant frequencies. Temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the device.
Article
Energy & Fuels
Tianshu Dong, Xiudong Duan, Yuanyuan Huang, Danji Huang, Yingdong Luo, Ziyu Liu, Xiaomeng Ai, Jiakun Fang, Chaolong Song
Summary: Electrochemical water splitting is crucial for hydrogen production, and improving the hydrogen separation rate from the electrode is essential for enhancing water electrolyzer performance. However, issues such as air bubble adhesion to the electrode plate hinder the process. Therefore, a methodology to investigate the two-phase flow within the electrolyzer is in high demand. This study proposes using a microfluidic system as a simulator for the electrolyzer and optimizing the two-phase flow by manipulating the micro-structure of the flow.
Article
Energy & Fuels
Shuo Han, Yifan Yuan, Mengjiao He, Ziwen Zhao, Beibei Xu, Diyi Chen, Jakub Jurasz
Summary: Giving full play to the flexibility of hydropower and integrating more variable renewable energy is of great significance for accelerating the transformation of China's power energy system. This study proposes a novel day-ahead scheduling model that considers the flexibility limited by irregular vibration zones (VZs) and the probability of flexibility shortage in a hydropower-variable renewable energy hybrid generation system. The model is applied to a real hydropower station and effectively improves the flexibility supply capacity of hydropower, especially during heavy load demand in flood season.
Article
Energy & Fuels
Zhen Wang, Kangqi Fan, Shizhong Zhao, Shuxin Wu, Xuan Zhang, Kangjia Zhai, Zhiqi Li, Hua He
Summary: This study developed a high-performance rotary energy harvester (AI-REH) inspired by archery, which efficiently accumulates and releases ultralow-frequency vibration energy. By utilizing a magnetic coupling strategy and an accumulator spring, the AI-REH achieves significantly accelerated rotor speeds and enhanced electric outputs.
Article
Energy & Fuels
Yi Yang, Qianyi Xing, Kang Wang, Caihong Li, Jianzhou Wang, Xiaojia Huang
Summary: In this study, a novel hybrid Quantile Regression (QR) model is proposed for Probabilistic Load Forecasting (PLF). The model integrates causal dilated convolution, residual connection, and Bidirectional Long Short-Term Memory (BiLSTM) for multi-scale feature extraction. In addition, a Combined Probabilistic Load Forecasting System (CPLFS) is proposed to overcome the inherent flaws of relying on a single model. Simulation results show that the hybrid QR outperforms traditional models and CPLFS exceeds the best benchmarks in terms of prediction accuracy and stability.
Article
Energy & Fuels
Wen-Jiang Zou, Young-Bae Kim, Seunghun Jung
Summary: This paper proposes a dynamic prediction model for capacity fade in vanadium redox flow batteries (VRFBs). The model accurately predicts changes in electrolyte volume and capacity fade, enhancing the competitiveness of VRFBs in energy storage applications.
Article
Energy & Fuels
Yuechao Ma, Shengtie Wang, Guangchen Liu, Guizhen Tian, Jianwei Zhang, Ruiming Liu
Summary: This paper focuses on the balance of state of charge (SOC) among multiple battery energy storage units (MBESUs) and bus voltage balance in an islanded bipolar DC microgrid. A SOC automatic balancing strategy is proposed considering the energy flow relationship and utilizing the adaptive virtual resistance algorithm. The simulation results demonstrate the effectiveness of the proposed strategy in achieving SOC balancing and decreasing bus voltage unbalance.
Article
Energy & Fuels
Raad Z. Homod, Basil Sh. Munahi, Hayder Ibrahim Mohammed, Musatafa Abbas Abbood Albadr, Aissa Abderrahmane, Jasim M. Mahdi, Mohamed Bechir Ben Hamida, Bilal Naji Alhasnawi, A. S. Albahri, Hussein Togun, Umar F. Alqsair, Zaher Mundher Yaseen
Summary: In this study, the control problem of the multiple-boiler system (MBS) is formulated as a dynamic Markov decision process and a deep clustering reinforcement learning approach is applied to obtain the optimal control policy. The proposed strategy, based on bang-bang action, shows superior response and achieves more than 32% energy saving compared to conventional fixed parameter controllers under dynamic indoor/outdoor actual conditions.