Article
Thermodynamics
Fuxu Quan, Juntao Chang, Chen Kong, Chengkun Lv, Guangwei Wu
Summary: This study investigates the fuel injection strategy and the effect of supplemental oxygen on the mixing performance in a scramjet combustor through large eddy simulations. The results show that injecting fuel from the upstream nozzle enhances mixing efficiency compared to the downstream nozzle. Additionally, supplementing oxygen at the trailing edge of the strut significantly improves turbulence and enhances fuel and oxidizer mixing.
APPLIED THERMAL ENGINEERING
(2024)
Article
Chemistry, Physical
A. C. Rajesh, S. Jeyakumar, Kandasamy Jayaraman, Mehmet Karaca
Summary: This study investigates the flow performance of a dual wall-mounted cavities in a strut-injector mounted scramjet combustor under steady-state and transient reacting conditions. The research compares two-dimensional Reynolds Averaged Navier-Stokes approach and Delayed Detached Eddy Simulation for computing the steady and unsteady flow characteristics. The results show that the dual cavities arrangement accelerates complete combustion and modifies the flow structures due to intense shock shear layer interactions.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Energy & Fuels
Junjie Miao, Yuxin Fan, Weiqiu Wu, Shilong Zhao
Summary: The novel air-assistant design proposed for cavity-strut based combustor can widen the ignitable space for ignition, extend the flammable Mach number, and decrease the lean ignition and blowout fuel/air ratio. The introduction of air-assistant method regulates the flame structure, enhances flame stability, and increases the temperature rise of combustor within the full range of operating fuel/air ratio.
Article
Mechanics
Prasanth P. Nair, Abhilash Suryan, Vinod Narayanan
Summary: Combustion at supersonic speeds is crucial for improving performance. The research discovers that the divergence angle of the passive strut has an impact on the mixing efficiency and acoustic behavior. Unstable combustion occurs when the divergence angle is too high, while pressure loss decreases with a smaller divergence angle.
Article
Thermodynamics
Hongchao Qiu, Junlong Zhang, Guangjun Feng, Juntao Chang, Wen Bao
Summary: This study presents the design of an axisymmetric variable geometry scramjet combustor equipped with a strut flame holder. Numerical calculations and experiments were conducted to investigate the performance of the combustor. The results demonstrate that the designed combustor can operate effectively in a wide range of flight Mach numbers, with good performance at high Mach numbers.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Physical
Long Gao, Xin Yu, Jiangbo Peng, Ye Tian, Zhen Cao, Fuyu Zhong, Guohua Wu, Minghong Han
Summary: This study investigates the combustion and oscillation behaviors in a hydrogen-fueled cavity-stabilized scramjet combustor using a high-speed PLIF technique. The spatial distribution of the flame structure under different fuel injection conditions is studied. The results reveal the shift in flame peak position downstream of the cavity with increasing injection pressure. The dynamic characteristics of flames under different flow conditions are analyzed, and the correlation between flame features and hydrogen injection conditions is obtained.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Aerospace
Singeetham Pranaykumar, Dinesh Mengu, Akshay Prakash
Summary: An innovative air-throttling injection mechanism is proposed and investigated in this study, aiming to improve the combustion efficiency and mixing efficiency in scramjets. The mechanism shows promising results in terms of flame stabilization, combustion efficiency, and shorter ignition length even at higher Mach numbers.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Hongchao Qiu, Guowei Luan, Guangjun Feng, Junlong Zhang, Wen Bao
Summary: This study investigates the effect of fuel injection methods on flame oscillation characteristics in an annular combustor. Experimental results show that the flame exhibits different oscillation modes and frequencies under different injection conditions, which are related to pressure gradients and combustion modes. Increasing the spacing between injection struts can alleviate flashback issues.
Article
Chemistry, Physical
Sai Sreekar Yarasai, Dineshkumar Ravi, Sharan Yoganand, Thundil Karuppa Raj Rajagopal
Summary: A numerical investigation was conducted to analyze the performance and combustion characteristics of a scramjet combustor with and without a cavity. Different geometrical shapes of injectors were considered, including circle, square, and rectangle. The results showed that the circular injector with a cavity exhibited better mixing and combustion characteristics compared to the other injector models.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Aerospace
Junlong Zhang, Libo Lin, Kai Yong, Wen Bao
Summary: This paper investigates the flame characteristics of a strut-equipped supersonic combustor fueled by liquid kerosene under incident shock waves through numerical simulation and experiments. The study found that the relative position between the strut and wedge significantly affects ignition, and changing the wedge installation direction and reducing the inlet Mach number can capture the effect of the flame characteristics affected by the incident shock wave more easily. The results show that the incident shock wave keeps the flame oscillation frequency around 170 Hz, and the engine thrust is hardly affected.
Article
Green & Sustainable Science & Technology
S. K. Kireeti, G. Ravi Kiran Sastry, S. K. Gugulothu, B. Deepanraj, L. Syam Sundar, M. Arthi
Summary: A numerical study compared the fluid flow characteristics of three and four-strut injectors, finding that the enhanced formation of recirculation regions and vortices, as well as increased shock wave interactions, contributed to better combustion performance with four-strut injectors.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Chemistry, Physical
Prasanth P. Nair, Vinod Narayanan, Abhilash Suryan
Summary: In a study on Scramjet engines, the placement of trailing struts plays a crucial role in enhancing combustion efficiency. Different strut configurations have varying effects on combustion performance, with configurations introducing high-pressure regions outperforming others. The addition of trailing struts leads to increased combustion efficiency and total pressure loss in the engine.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
A. C. Rajesh, S. Jeyakumar, Kandasamy Jayaraman, Mehmet Karaca, A. Antony Athithan
Summary: The effect of dual cavity locations with strut injection configuration on supersonic flow under reacting conditions is evaluated numerically. The study investigates the shock wave patterns and their association with shear layer mixing features at different locations of the top wall cavity and bottom wall cavity. The flow pattern, static pressure and temperature distributions, and performance analysis of the dual cavity designs associated with the results of the DLR scramjet are analyzed.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Aerospace
Huimin Tian, Junlong Zhang, Hongchao Qiu, Wen Bao, Songjing Li
Summary: This study achieved stable supersonic combustion in a scramjet combustor fueled by liquid kerosene with the help of an O2-pilot strut. The effect of different mass flow rate of oxygen on cold flow and combustion characteristics was investigated, and the results showed that adjusting the mass flow rate of oxygen improved the combustion zone around the ignitor. However, excessive or insufficient oxygen resulted in delayed ignition or increased flame lift distance.
Article
Chemistry, Physical
Jincheng Zhang, Zhenguo Wang, Chaoyang Liu, Mingbo Sun, Hongbo Wang
Summary: This paper applies numerical simulation to investigate the combustion characteristics in a lobed strut-stabilized scramjet combustor under different flight conditions. The results show that the streamwise vortices induced by the lobed strut enhance mixing and promote stable combustion. Analysis of probability density function reveals the competitive relationship between auto-ignition mode and flame mode influenced by the Mach number.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Aerospace
Youyin Wang, Wen Shi, Xuan Wang, Junlong Zhang, Jin Gao, Jingfeng Tang, Juntao Chang, Wen Bao
Summary: This study investigates a 20-degree deflection angle wave-elimination variable geometry combustor, demonstrating through numerical simulations and experimental tests its superior performance in a wide range of operating speeds, especially at high Mach numbers. The wave-elimination design improves the total pressure recovery coefficient of the combustor under different conditions, showing significant advantages for improving the performance of variable-geometry combustors in future hypersonic aircrafts.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Jingying Zuo, Dingyuan Wei, Silong Zhang, Jiang Qin, Wen Bao, Naigang Cui
Summary: Film cooling is an effective method for achieving thermal protection and reducing skin friction in scramjet combustors. Combustion of the coolant film has double effects on film cooling performance and reduces skin friction. Additionally, shock waves generated after ignition of hydrocarbon fuel significantly influence skin friction distribution.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Mechanics
Nan Li, Juntao Chang, Kejing Xu, Daren Yu, Wen Bao
Summary: The study investigated the unstable behavior of a shock train system in a back pressured duct with incident shocks. It found that as the shock train enters the SWBLI region, divergent vibration emerges, leading to instability. An analysis based on the feedback mechanism identified a criterion for this instability.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Aerospace
Hongchao Qiu, Junlong Zhang, Jin Gao, Juntao Chang, Wen Bao
Summary: An experimental study was conducted on a strut/wall combined fuel injection scheme in a flush-wall scramjet combustor fueled with liquid kerosene. Results showed that increasing fuel equivalence ratio enhances core flame and leads to the formation of wall flame, while optimizing the position of wall fuel injectors can improve combustion efficiency.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Youyin Wang, Wenxin Hou, Junlong Zhang, Jingfeng Tang, Juntao Chang, Wen Bao
Summary: This paper analyzes the pressure rise mechanism of the dual mode scramjet engine and the characteristic of the isolator maximum pressure rise. The operating range and performance of the scramjet under the pressure rise limit are investigated using a constant cross-sectional area combustor. The study suggests a variable divergent section to balance pressure under different freestream Mach numbers and equivalence ratios.
Article
Engineering, Aerospace
Ji Li, Jingfeng Tang, Junlong Zhang, Ximing Zhu, Haoran Zhang, Wen Bao, Daren Yu
Summary: The paper explores the establishment process of flame with a plasma igniter in an axisymmetric kerosene combustor under certain conditions and investigates several typical flameholding modes and their influencing factors. It reveals that a weak flame can spontaneously transform into a stronger flame during the flame establishment process, and classifies flameholding into four types.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Hongchao Qiu, Junlong Zhang, Guangjun Feng, Juntao Chang, Wen Bao
Summary: This study presents the design of an axisymmetric variable geometry scramjet combustor equipped with a strut flame holder. Numerical calculations and experiments were conducted to investigate the performance of the combustor. The results demonstrate that the designed combustor can operate effectively in a wide range of flight Mach numbers, with good performance at high Mach numbers.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Aerospace
Lihan Li, Xin Li, Jiang Qin, Silong Zhang, Wen Bao
Summary: This study conducted numerical simulations to investigate the impact of dimple depth-diameter ratio on the cooling channel of a scramjet. The results showed that increasing the ratio can improve heat transfer efficiency but also increase pressure loss. The optimal depth-diameter ratio for hydrocarbon fueled regenerative cooling channels was found to be 0.2.
INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING
(2021)
Article
Thermodynamics
Jianfei Wei, Silong Zhang, Jingjia Xue, Xingyu Zhou, Jiang Qin, Wen Bao
Summary: Film cooling using gaseous hydrocarbon fuel is an effective method to meet the requirements of thermal protection and friction reduction in hydrocarbon-fueled scramjet engines. The characteristics of the hydrocarbon film cooling and friction reduction are influenced by the wall thermal state through chemical reactions. Numerical investigations show that wall cooling heat flux has a positive effect on film cooling performance but a negative effect on friction reduction performance. The endothermic chemistry in the hydrocarbon film can enhance cooling comparable to regenerative cooling, but the wall shear stress is less sensitive to the wall thermal state.
APPLIED THERMAL ENGINEERING
(2022)
Review
Engineering, Aerospace
Yunfei Li, Juntao Chang, Chen Kong, Wen Bao
Summary: This article provides an overview of the development and applications of machine learning in the field of fluid mechanics. Machine learning offers a wide range of analysis methods for understanding flow mechanisms and for practical applications. Machine learning algorithms can enhance flow information and perform tasks automatically.
CHINESE JOURNAL OF AERONAUTICS
(2022)
Article
Thermodynamics
Xin Pan, Yuefei Xiong, Cong Wang, Jiang Qin, Silong Zhang, Wen Bao
Summary: Precooling is crucial for hydrocarbon-fueled TBCC engines to expand the flight Mach number and improve specific impulse. The low-temperature endothermic fuel precooling scheme shows great potential in enhancing heat sink and overall performance.
Article
Thermodynamics
Xin Pan, Jiang Qin, Silong Zhang, Wen Bao
Summary: Precooling technology with a low-temperature endothermic fuel is a potential solution for the reduction of specific impulse in hydrocarbon-fueled turbojet engines. Methanol cracking reaction can enhance the cooling effect but may decrease the compactness of the precooler with an increase in the longitudinal pitch-to-diameter ratio. Decreasing the transverse pitch-to-diameter ratio can increase the cooling effect but will result in significant pressure loss.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Review
Engineering, Aerospace
Chengkun Lv, Juntao Chang, Wen Bao, Daren Yu
Summary: The paper provides a summary report on recent research progress in the control of airbreathing aero-engines, covering different control problems and methods, as well as issues related to hypersonic flight and turbine-based combined cycle engines. It serves as a useful reference for researchers working in this field.
PROPULSION AND POWER RESEARCH
(2022)
Article
Engineering, Aerospace
Junlong Zhang, Libo Lin, Zhaohui Yao, Wen Bao
Summary: In this paper, the unstart boundary of the strut-equipped variable geometry combustor was experimentally verified at Mach 2 condition. The study focuses on the requirements of fuel equivalent ratio and combustor expansion ratio for the working boundary of the supersonic combustor. Through simulation analyses and static regulations, the optimization of flow field structure and successful ignition were achieved. Experimental investigations were then conducted to adapt the fuel equivalent ratio and expansion ratio for performance enhancement, leading to qualitative and quantitative conclusions about the starting boundary and performance distribution pattern of the combustor.
Article
Thermodynamics
Kunlin Cheng, Jiang Qin, Duo Zhang, Wen Bao, Wuxing Jing
Summary: The closed-Brayton-cycle (CBC) power generation system is a potential high-power electricity generation scheme for hypersonic vehicles, but it is limited by finite cold source onboard. This study proposes a combined power generation system based on supercritical carbon dioxide closed-Brayton-cycle and multi-stage thermoelectric generator (TEG) to extend the available temperature range of the cold source and increase electric power output.
Article
Engineering, Aerospace
Andre F. P. Ribeiro, Carlos Ferreira, Damiano Casalino
Summary: This study compares a filament-based free wake panel method to experimental and validated numerical data in order to simulate propeller slipstreams and their interaction with aircraft components. The results show that the free wake panel method is able to successfully capture the slipstream deformation and shearing, making it a useful tool for propeller-wing interaction in preliminary aircraft design.
AEROSPACE SCIENCE AND TECHNOLOGY
(2024)
