Article
Mechanics
Veeresh Tekure, K. Venkatasubbaiah
Summary: Numerical study of conjugate heat transfer in supersonic turbulent flow over a flat plate with finite thickness shows lower interface temperature and fluid temperature variation compared to non-conjugate heat transfer analysis. Results indicate significant increase in interface temperature for low thermal conductivity plate materials, and negligible effect of plate thickness on flow field temperature variation. Additionally, the maximum interface temperature increases with plate thickness.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2021)
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
Engineering, Aerospace
Augusto F. Moura, Nicholas Gibbons, Vincent Wheatley, Ingo Jahn
Summary: Oxygen enrichment significantly increases combustion efficiency in scramjet engines, without significantly altering the overall turbulent combustion, which is distributed over a wide range of regimes.
Article
Engineering, Marine
Xiumao Du, Peng Yuan, Junzhe Tan, Xiancai Si, Yonghui Liu, Shujie Wang, Xianpeng Lang
Summary: This study analyzes the influence of the support structure design on the performance of a diffuser-augmented hydrodynamic turbine. Blade-resolved Computational Fluid Dynamics (CFD) numerical simulations are used to analyze the effects of parameters such as support distance, the number of columns, and the aspect ratio of the support structure. The results show that support structures can significantly reduce the acceleration ratio and power coefficient of the turbine.
Article
Chemistry, Multidisciplinary
Xianju Wu, Zhijun Wei
Summary: A computational fluid dynamics numerical simulation was conducted to compare the performances of a dual-combustion ramjet (DCR) and a scramjet, providing theoretical guidance for engine selection for a hypersonic vehicle. The DCR exhibited a central combustion mode with higher combustion efficiency compared to the near-wall combustion mode of the scramjet. The performance advantage of the DCR decreased as the Mach number increased.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Aerospace
Lan Zhang, Zhi-qiang Sheng, Yu Dan, Liang-ze Lu
Summary: In this study, two new strut configurations (BS-1 and BS-2) were proposed to improve the combustion performance of a scramjet combustor. The effects of these configurations on the flow disturbance, streamwise vortices, and combustion efficiency were investigated using numerical simulation methods. The results demonstrated that the BS struts significantly increased the combustion efficiency by enhancing the turbulent-kinetic-energy region, expanding the combustion region, and improving heat and mass convection. BS-2 had a stronger disturbance effect on the flow and induced stronger streamwise vortices, resulting in a greater total pressure loss compared to BS-1.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Energy & Fuels
A. Antony Athithan, S. Jeyakumar, Norbert Sczygiol, Mariusz Urbanski, A. Hariharasudan
Summary: This paper investigates the influence of ramps located upstream of a strut-based scramjet combustor under reacting flow conditions. The numerical results are validated with experimental values, showing compliance within the range, and the shock reflection due to the ramps enhances hydrogen distribution in the spatial direction, while lowering the combustion ignition delay time.
Article
Engineering, Aerospace
Pedro P. B. Araujo, Marcos V. S. Pereira, George S. Marinho, Joao F. A. Martos, Paulo G. P. Toro
Summary: This work presents a two-dimensional mixed compression scramjet inlet design based on conditions required to burn hydrogen spontaneously at supersonic speeds. The design considers air as a calorically perfect gas and applies the criterion of equal shock strength to determine compression ramps angles and airflow properties. The optimization criteria are extended to analyze the inlet of a scramjet vehicle with 5 compression ramps flying at various speeds and altitudes.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Multidisciplinary
Kumari Ambe Verma, Krishna Murari Pandey, Mukul Ray, Kaushal Kumar Sharma
Summary: This article involves a computational investigation of a parallel fuel injection based scramjet combustor. By validating the selected geometry and changing the angle of attack of the incoming air, the variations in combustion efficiency are analyzed. The study results indicate that the performance of the scramjet combustor is primarily influenced by the geometry configuration and the nature of flow of incoming air.
RESULTS IN ENGINEERING
(2022)
Article
Engineering, Aerospace
Xianju Wu, Zhijun Wei
Summary: Dual-combustion ramjets combine the advantages of both ramjets and scramjets, and further research is needed to understand the combustion flow state and improve engine performance. This study used computational fluid dynamics to explore the two combustion modes, scramjet and ramjet, in a dual-combustion ramjet under the same conditions. The results showed that the ramjet mode had better engine performance compared to the scramjet mode.
Article
Thermodynamics
Mattia Samiolo, Patrick G. Verdin
Summary: This paper introduces the use of computational fluid dynamics in studying the transition from thermal to electrical propulsion in vehicle design. It establishes a procedure to develop and evaluate a prototype heat exchanger, and uses numerical methods to assess the aerodynamic performance of an electric vehicle equipped with the new heat exchanger. The comparison shows a 5% reduction in drag and overall weight with the newly designed system, proposing a new form of heat exchanger packaging.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Aerospace
Suyi Dou, Qingchun Yang, Yushu Jin, Xu Xu
Summary: This study investigates the combustion mode and mechanism in a scramjet engine. The experiments show that as the fuel equivalence ratio increases, the combustion mode transitions from premixed combustion to partially premixed combustion, and finally to diffusion combustion. The bilateral injection scheme is more advantageous for premixed combustion. Inflow total temperature has an impact on combustion characteristics.
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
Engineering, Aerospace
Lan Zhang, Zhi-qiang Sheng, Yu Dan
Summary: A novel strut with sawtooth grooves was developed to improve the performance of a scramjet combustor. Numerical simulations demonstrated the flow fields of normal and novel struts at Mach number 2.0. The results showed that the novel strut with sawtooth grooves significantly enhanced the combustion process.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
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
Pritam Majumder, Krishna Murari Pandey, Nishikant Deshpande, Subhendu Maity
ADVANCES IN MECHANICAL ENGINEERING, ICRIDME 2018
(2020)
Proceedings Paper
Engineering, Mechanical
R. R. Kumar, K. M. Pandey, S. Dey
RELIABILITY, SAFETY AND HAZARD ASSESSMENT FOR RISK-BASED TECHNOLOGIES
(2020)