Article
Engineering, Aerospace
Yu Meng, Wenming Sun, Hongbin Gu, Fang Chen, Ruixu Zhou
Summary: This study investigates the combustion mode and instability characteristics of scramjets using the POD method. Experimental observations of flow and combustion behavior were made on a scramjet model with a cavity stabilizer. The results provide insights into the oscillation characteristics of three typical stabilized combustion modes.
Article
Engineering, Aerospace
Fan Li, Guoyan Zhao, Yuhui Huang, Daoning Yang, Guangwei Ma, Yansong Li, Yixin Yang, Peibo Li, Jiajian Zhu, Mingbo Sun
Summary: This study investigates the effect of boundary layer thickness on supersonic combustion in an ethylene-fueled scramjet combustor under Mach 5.5 flight conditions using experiments, numerical simulations, and theoretical modeling. The study finds that while the absolute thickness of the boundary layer increases with a larger combustor, the relative thickness remains thin. The influence of boundary layer thickness on the transverse jet and cavity flow is limited, but the combustion is greatly affected by the combustion chamber scale change. Larger combustion chambers exhibit more violent flames. A theoretical model shows that a large subsonic region leads to a longer fuel residence time and larger Damkohler numbers, indicating the ability of a large combustor to sustain intense combustion. The relative thinness of the boundary layer contributes to intense combustion due to the increased absolute subsonic region filled with combustion products. The study also verifies that the combustion is significantly weakened in a 50 mm shortened isolation section through flame cloud diagrams and quantitative wall pressure data.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Shengzu Guo, Xu Zhang, Qili Liu, Lianjie Yue
Summary: The periodic flame flashback phenomenon was numerically studied in an ethylene-fueled scramjet combustor using a 3D unsteady Navier-Stokes solver. The study revealed that the combustion oscillations and flame flashbacks were maintained in the separated scramjet mode, not connected to the ramjet/scramjet mode transitions. A mechanism with four evolution stages was proposed to explain the flow-flame interaction.
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
Jianheng Ji, Zun Cai, Taiyu Wang, Zhenguo Wang, Mingbo Sun
Summary: This study investigates flame behaviors in a cavity-based scramjet combustor under supersonic inflow. The results show that increasing the equivalence ratio leads to a transition in combustion mode, and increasing the cavity aft wall height improves the combustor's self-ignition capability. Moreover, the application of spark plasma effectively suppresses low-frequency combustion oscillations.
Article
Engineering, Aerospace
Jianbin Li, Jianhan Liang, Mingbo Sun, Zun Cai, Lin Zhang
Summary: This study experimentally investigates the effect of inlet distortion on the combustion process in a direct-connect test environment. The results show that blockage at the entrance of the isolator can accurately mimic the inlet distortion. Combustion enhancement is achieved in cases with blockage, with wider lean blowoff limits in the combustor. The stronger oblique shock wave and additional background shock wave caused by the inlet distortion are the main causes of combustion enhancement in these cases.
AEROSPACE SCIENCE AND TECHNOLOGY
(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
Hongbo Wang, Xiliang Song, Liang Li, Yuhui Huang, Mingbo Sun
Summary: Experiments were conducted to investigate the near blowoff characteristics of cavity-stabilized flames in an ethylene-fueled scramjet combustor. It was found that there exists an optimal cavity size for ignition and flame stabilization near lean blowoff conditions, determined by the competition between flow residence time and local equivalence ratio.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Rong Feng, Mingbo Sun, Hongbo Wang, Yuhui Huang, Yifu Tian, Chao Wang, Xu Liu, Jiajian Zhu, Zhenguo Wang
Summary: This study investigates the effect of a multi-channel gliding arc (MCGA) plasma on flameholding in an ethylene-fueled scramjet combustor. The results show that the plasma is able to effectively hold the flame and increase the average flameholding time by 51%. The enhanced temperature in the cavity by the MCGA plasma improves the ignition delay time of the fuel, leading to improved flame stability.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Metallurgy & Metallurgical Engineering
Zhe Zhang, Xing Jin, Wen-xiong Xi
Summary: The study analyzed the combustion characteristics under different injection conditions, revealing that an increase in total pressure of strut fuel injection leads to a decrease in combustion efficiency. However, increasing the total pressure of strut fuel injection within a proper range can expand the combustion area downstream. Increasing the total pressure of cavity fuel injection within the range of 0.5-2.0 MPa expands the combustion range and improves combustion efficiency, but excessive total injection pressure of cavity fuel can result in a sharp drop in efficiency. Increasing the total injection pressure of the plasma jet raises the height of the cavity shear layer and improves the equivalence ratio of the gas mixture in the cavity, with a maximum combustion efficiency of 82.1% achieved at a total pressure of 1.25 MPa. The combustion-assisted effect of different plasma jet media varies significantly, with O2 having the most significant effect on the combustor.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2021)
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
Mingjiang Liu, Mingbo Sun, Guoyan Zhao, Yu Meng, Yuhui Huang, Guangwei Ma, Hongbo Wang
Summary: The relationship between thrust performance and combustion mode in a scramjet combustor was investigated through numerical simulations and experiments to verify the reliability of the numerical method. Different combustion modes were identified, and the impact of these modes on thrust performance and the possibility for performance improvement under different Mach numbers were discussed.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Aerospace
Suneetha Lakka, Pitambar Randive, K. M. Pandey
Summary: The study compares the combustion characteristics of combustors with and without cavities and investigates the impact of cavity parameters on the performance of a strut-based scramjet combustor. The research reveals the formation of a strong recirculation zone in the cavity region, improving mixing and combustion efficiency.
Article
Mechanics
Jian Fang, Xi Deng, Zhi X. Chen
Summary: A Mach 1.5 non-reactive flow in a cavity-stabilized combustor of a model scramjet was studied via direct-numerical simulation, with focus on the interaction among boundary layer, free shear-layer above the cavity and shock wave. Impingement of the free shear-layer on the aft wall of the cavity leads to strong turbulence, high pressure, and compression waves. The analysis reveals that shear production amplifies turbulence in the core of the shear-layer, while deceleration production has a significant impact above the aft wall of the cavity and around the shock interaction points.
Article
Engineering, Aerospace
Yuwei Cheng, Qian Chen, Xiaofei Niu, Shufeng Cai
Summary: This paper investigates the supersonic combustion instability in a strut-based scramjet combustor using large eddy simulation and dynamic mode decomposition. The results show significant pressure oscillation in the combustor under certain conditions, which are related to wake instability, shear layer instability, shear layer and wave interactions, and combustion.
Article
Thermodynamics
Pinku Debnath, K. M. Pandey
Summary: The study investigates the effect of modified ejector on detonation combustion wave propagation and propulsion thrust of liquid kerosene and gaseous hydrogen-air mixture. Simulation results show that the thrust force augmentation of hydrogen-air mixture is greater compared to liquid kerosene-air mixture, but the flame propagation velocity is faster for hydrogen-air combustion.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Engineering, Aerospace
Lakka Suneetha, Pitambar Randive, K. M. Pandey
Summary: The study reveals that self-throttling significantly affects the combustion performance of a strut-based scramjet combustor, improving mixing efficiency and enhancing fuel combustion. Additionally, the key factor influencing performance is the distance of self-throttling from the inlet.
Article
Engineering, Multidisciplinary
Namrata Bordoloi, Krishna Murari Pandey, Kaushal Kumar Sharma
Summary: The study reveals that analyzing the supersonic combustor ramjet engine through a simulation model can effectively replicate experimental results. Different incoming Mach numbers result in varying combustion and mixing efficiencies. The maximum temperature rise is 2711.467 K, with maximum combustion and mixing efficiencies of 87.47% and 98.15% respectively.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2021)
Article
Thermodynamics
Prince Kumar, Krishna Murari Pandey
Summary: A comprehensive numerical analysis was conducted to examine the transport characteristics of flow of Newtonian fluid inside a channel with a porous slab and internal wavy walls. It was found that heat transfer rate and pressure drop increase with rising Reynold number, Darcy number, and wavy wall's amplitude. Additionally, the enhancement ratio (ER) reaches its maximum value of 10.8 for Da = 10(-2) and Re = 1200.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2021)
Article
Engineering, Multidisciplinary
Akhileshwar Singh, Krishna Murari Pandey, Yogesh Singh
Summary: This study investigates the splitting dynamics of low-viscous fingers inside bifurcating channels through the manipulation of surface wettability. Numerical simulations reveal that the behavior of finger splitting depends on various parameters, including surface wettability, capillary number, viscosity ratio, and surface tension. The findings provide insights into biofluid mechanics and respiratory diseases such as COVID-19.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Durgesh Kumar Mishra, Sumit Bhowmik, Krishna Murari Pandey
Summary: This study discusses the thermal exploration of melting phenomena of beeswax-based phase change material of four different annulus shapes. Numerical investigation on composite-beeswax approach with metal oxide particles revealed improved melting rate and heat transfer. The type of metal oxide particles had minimal impact on melting rate and heat transfer, showing significant enhancements with their presence.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Dipak Debbarma, Krishna Murari Pandey, Abhishek Paul
Summary: This study investigates the enhancement of overall performance in heat sinks by using a double layer structure with protrusions and dimples. Comparisons between microsinks with protruded-dimpled bottom layer and microsinks with protruded-dimpled layers were made, with staggered arrangements showing superior overall performance. The heat sink with both layers protruded and dimpled was found to be optimal, offering excellent thermal performance.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Bandi Venkata Ramana Reddy, Saikat Ranjan Maity, Lokeswar Patnaik, Sunil Kumar, Krishna Murari Pandey
Summary: Al-6Si-18Pb alloy was fabricated using spray deposition method and warm rolling, and the microstructural change and mechanical properties were studied. The results showed that continuous and discontinuous dynamic recrystallisation occurred in the alloy after warm rolling, resulting in grain refinement. Furthermore, Pb atoms were homogeneously distributed in the Al matrix. The porosity and hardness of the samples were significantly affected after warm rolling.
ADVANCES IN MATERIALS AND PROCESSING TECHNOLOGIES
(2022)
Article
Thermodynamics
Prince Kumar, Ritesh Dwivedi, K. M. Pandey
Summary: This study numerically investigates the impact of different Prandtl numbers on the thermo-hydraulic transport characteristics of a partial porous wavy channel for a laminar flow. The results show that increasing the Prandtl number and Reynolds number leads to an increase in the Nusselt number and enhancement ratio, while the performance factor deteriorates with increasing slab thickness. Additionally, the effect of different Darcy numbers was evaluated.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Thermodynamics
Prince Kumar, K. M. Pandey
Summary: This article investigates the effect of varying porous slab thicknesses and Darcy number on the thermohydraulic performance of corrugated channels. The results show that increasing the porous slab thickness and decreasing the Darcy number can enhance the thermal performance but reduce the hydraulic performance.
Article
Thermodynamics
Prince Kumar, Ritesh Dwivedi, Krishna Murari Pandey
Summary: Comprehensive numerical simulations are conducted to investigate the combined effect of three distinct passive techniques on thermo-hydraulic properties and entropy generation in three different wavy channels. It is found that the insertion of porous media between the corrugated walls enhances thermal performance, and the trapezoidal channel shows the highest enhancement by 90%.
HEAT TRANSFER ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Akhileshwar Singh, Deepak Kumar Singh, Yogesh Singh, Krishna Murari Pandey
Summary: This paper investigates the influence of viscosity ratio and surface wettability on immiscible viscous fingering instability within a rectangular channel. The findings reveal that higher viscosity ratios lead to increased displacement efficiency, while low viscosity ratios result in necking. The finger-shaped pattern splits into two parts at a wettability of 15 degrees, and no splitting occurs beyond this threshold. Furthermore, a transition from hydrophilic to superhydrophobic wettability abolishes necking and enhances displacement efficiency, with the instability shifting towards the left side.
INTERNATIONAL JOURNAL OF MODERN PHYSICS C
(2023)
Proceedings Paper
Materials Science, Multidisciplinary
Plabita Sonowal, K. M. Pandey, K. K. Sharma
Summary: Landing gear design is a crucial aspect in aircraft design, with shock absorbers being one of the key components that need to be carefully designed. This study focused on the structural analysis of a landing gear shock absorber model for the Boeing 787-8 in static conditions, with results showing that the high strength stainless steel model exhibited lower stress and deformation.
MATERIALS TODAY-PROCEEDINGS
(2021)
Proceedings Paper
Engineering, Mechanical
R. R. Kumar, K. M. Pandey, S. Dey
RELIABILITY, SAFETY AND HAZARD ASSESSMENT FOR RISK-BASED TECHNOLOGIES
(2020)
Proceedings Paper
Materials Science, Multidisciplinary
Babar Pasha Mahammod, Emon Barua, Ashish B. Deoghare, K. M. Pandey
MATERIALS TODAY-PROCEEDINGS
(2020)
