Article
Computer Science, Interdisciplinary Applications
Martin A. Di Stefano, Serhat Hosder, Robert A. Baurle
Summary: The study investigates the impact of turbulence model closure coefficient uncertainty on the Reynolds-averaged Navier-Stokes solution of a scramjet strut fuel injector flow field using Menter-BSL and Wilcox-2006 k-omega turbulence models. It identifies influential sets of closure coefficients and aims to assist in reducing uncertainty in the numerical design of scramjet fuel injectors.
COMPUTERS & FLUIDS
(2021)
Article
Energy & Fuels
Gautam Choubey, Parth Gaud, Abdulnasser Mahmood Fatah, Yuvarajan Devarajan
Summary: Geometric variation has a significant influence on the performance study of a supersonic combustor. Increasing the ramp position leads to a slight improvement in combustion efficiency but also increases total pressure loss. Additionally, increasing the divergence angle on both walls weakens the combustion performance to some extent.
Article
Engineering, Aerospace
D. R. Biju Ben Rose, B. T. N. Sridhar
Summary: Cold flow experiments were conducted on a laboratory model of a scramjet thruster to study the effects of adjusting the position and height of a rectangular strut on the control of side force and pitching moment. The results suggest that these adjustments can effectively manipulate the aerodynamic forces and are thus significant for the control of hypersonic vehicles.
Article
Engineering, Marine
Mehmet Seyhan, Hurrem Akbiyik, Mustafa Sarioglu, Sevda Ceren Kececioglu
Summary: An experimental study was conducted to investigate the impact of leading-edge tubercles on the aerodynamic characteristics of an airfoil, showing that airfoils with leading-edge tubercles have higher lift, closer streamwise vortices, and increased turbulence. The T3 airfoil model performed the best in terms of lift, drag, and CL/CD ratios.
Article
Energy & Fuels
Gautam Choubey, Malhar Solanki, Om Patel, Yuvarajan Devarajan, Wei Huang
Summary: The shape of the struts significantly affects the combustion mechanism in scramjet engines. Researchers have found that a semi-circular trailing edge half-wedge strut is the most effective configuration, ensuring better combustion performance. Increasing the inward fuel injection angle improves the mixing performance of the two-strut scramjet combustor.
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
Energy & Fuels
Obula Reddy Kummitha, K. M. Pandey
Summary: The global demand for enhanced scramjet engine performance is increasing, with the main challenge being the mixing of fuel and air. Research has shown that using a wavy wall surface and double strut fuel injector can significantly improve mixing efficiency and combustion phenomenon.
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
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
Engineering, Aerospace
Donggang Cao, Dan Michaels
Summary: In this paper, a hybrid Reynolds-averaged Navier-Stokes/large-eddy simulation investigation is conducted to study a strut-based scramjet. Both nonreacting and reacting cases are studied, and the vorticity and its influencing factors are analyzed. Multiple mechanisms contribute to vorticity transport simultaneously but unequally in different regions.
Article
Thermodynamics
W. Q. Li, Z. R. Xue, H. B. Ke, H. Wan, X. G. Wei, F. Qin, G. Q. He
Summary: The study demonstrated an internally-cooled strut injector with a coiled and miniature-sized cooling configuration that could operate at a low coolant mass flow rate of 10 g/s. This design showed superior heat transfer coefficient and heat flux compared to previous designs, with the potential for improved thermal safety and combustion efficiency in scramjet combustors.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Engineering, Aerospace
Wei Yao, Hang Liu, Lianjie Xue, Yabing Xiao
Summary: The study found that a full-scale scramjet engine can achieve net thrust in the range of low dynamic pressure below 37 kPa and high range above 55 kPa, with combustion efficiencies varying from 66% to 82%. The rule of mixed is burnt was observed along with upstream propagation of combustion. However, unstart may occur in specific cases, such as Mach 7 at 30 km altitude.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
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
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
Subhasis Chakravarthy, Pitambar Randive, Sukumar Pati
Summary: This study numerically investigated the effect of air throttling on the combustion performance of an ethylene-fueled scramjet combustor, showing that the flow rate and location of throttling have a strong interplay with combustion efficiency. The introduction of air throttling enhanced combustion efficiency due to the generation of pre-combustion shock train, with optimum efficiency achieved when throttling is about 20% of the inlet mass flow rate at a specific distance downstream from the cavity.
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
Jingying Zuo, Silong Zhang, Jiang Qin, Wen Bao, Naigang Cui, Oskar J. Haidn
Summary: This paper numerically investigates the interaction between oblique shock waves and hydrocarbon fueled supersonic film cooling with combustion using Reynolds-averaged Navier-Stokes equations. It is found that the shock wave reflects on the flame and induces small-momentum region on the wall, leading to an increase in reflected shock wave intensity. Additionally, the interaction between shock waves and combustion reduces the beneficial cooling performance and increases the skin friction reduction region.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Wanqian Xu, Junlong Zhang, Chenguang Zhong, Juntao Chang, Wen Bao
Summary: An algorithm for noncontact portable temperature measurement sensors for scramjet combustion chambers has been developed, comparing the inversion capabilities of OH radical emission spectra using multilayer perceptron and convolutional neural networks. Noise levels in the measurements were considered, with the convolutional neural network showing promising results with added random Gaussian noise.
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
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.
