Article
Mechanics
Jian Teng, Jianchun Wang, Hui Li, Shiyi Chen
Summary: Interscale kinetic energy transfer in chemically reacting compressible isotropic turbulence is influenced by heat release of exothermic reactions, intensifying multiple components of kinetic energy transfer and increasing both forward and backward scattering effects.
JOURNAL OF FLUID MECHANICS
(2021)
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
Mechanics
Sajjad Mohammadnejad, Leslie Saca, Sina Kheirkhah
Summary: A new compact active turbulence generator has been developed, which can generate large eddies and dissipate turbulent energy faster.
Article
Mechanics
Shuvayan Brahmachary, Ananthakrishnan Bhagyarajan, Hideaki Ogawa
Summary: This study combines fluid mechanics and machine learning to develop a new approach for fast and accurate prediction of internal flowfields in hypersonic airbreathing propulsion scramjet intakes. It highlights the importance of tuning parameters and using multiple reduced-order bases, as well as the potential of utilizing bias in building a reduced-order predictive framework in optimization problems.
Article
Thermodynamics
Alex Krisman, Patrick Meagher, Xinyu Zhao, Ji-Woong Park, Tianfeng Lu, Jacqueline H. Chen
Summary: This study investigates flame quenching mechanisms in aeronautical engines through numerical simulations, revealing flame shortening and high flame stretch as two extinction mechanisms, with local balance determining the propensity for local extinction.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Physical
Obula Reddy Kummitha
Summary: This study investigates the effect of parallel and inclined fuel injection in the strut flame holder wake region. The results show that inclined injection significantly improves mixing and combustion efficiency.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Mechanics
Jonathan L. L. Palafoutas, William A. A. Sirignano
Summary: This study analyzes a three-dimensional laminar shear-layer flow under a boundary-layer approximation, considering mixing, chemical reaction, and imposed strain. It aims to determine if stretched vortex layers in turbulent combustion result from spatially developing shear flows with compressive strain. The reduced-order asymptotic solutions provide valuable insights for developing flamelet models in turbulent combustion simulations.
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
Engineering, Aerospace
Tristan Vanyai, Stefan Brieschenk, Mathew Bricalli, Tamara Sopek, Timothy J. McIntyre
Summary: Experimental study shows that thermal compression can directly increase combustion-induced pressure rise in a non-uniform scramjet flowpath. Injection of helium in half of the combustor can suppress combustion.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Srinivas Prasad Sanaka, Ramanaiah Kandula, Khyathi Sree Chalamalasetty, Durga Rao Kappala
Summary: The study aims to understand the influence of fuel mass flow rate and flight speed on combustion in scramjet engine. A DLR conical strut based scramjet combustor configuration was chosen and chemical reaction between air and hydrogen fuel was simulated. The effects of temperature, velocity distribution, and flow structure on the combustion process were analyzed and validated using the ICEM CFD software and ANSYS fluent solver. The results showed that the peak temperature increased with the flight speed and inlet fuel mass flow rate, reaching around 3500 K at a Mach 4 flight speed.
INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES
(2023)
Article
Engineering, Environmental
Yi Ouyang, Laurien A. Vandewalle, Lin Chen, Pieter P. Plehiers, Maarten R. Dobbelaere, Geraldine J. Heynderickx, Guy B. Marin, Kevin M. Van Geem
Summary: This study combines the power of deep artificial neural networks with turbulent reactive flow simulation to improve computational efficiency, resulting in simulations that are an order of magnitude faster without compromising accuracy. The approach was successfully demonstrated using the Lagrangian Monte Carlo method, showcasing the potential of this data-driven deep learning method in accelerating time-consuming models in the field of reactive flow simulation.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Obula Reddy Kummitha, K. M. Pandey, Anil Kumar Reddy Padidam
Summary: The research introduces an innovative fuel injection strut to enhance mixing performance by increasing interactions between shock wave and shear mixing layer. Numerical analysis shows that the new strut significantly improves mixing efficiency compared to the basic wedge design.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Erica Quadarella, Arthur Pequin, Alessandro Stagni, Alessandro Parente, Tiziano Faravelli, Hong G. Im
Summary: A generalized Partially-Stirred Reactor (PaSR) model is proposed in this study, which includes multiple chemical times and provides an extension of the Eddy Dissipation Concept (EDC). The approach aims to include the whole set of chemical times involved in the reactive system and characterizes species production rates instead of fine structures. The method is validated with DNS data and shows good agreement with the filtered data, demonstrating the limitations of the old standard approach and the importance of including the whole spectrum of chemical times for a comprehensive description of turbulence-chemistry interaction.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Mechanics
Ellen K. Luckins, James M. Oliver, Colin P. Please, Benjamin M. Sloman, Robert A. Van Gorder
Summary: The study focuses on endothermic reactions and the flow of granular solid reactants powered by hot gas counter-current flow. It explores various heat-transfer rate values and identifies six distinguished limits, with a diffusive boundary layer for high temperatures. The research shows that the direction of net heat flux affects the solution structure in the single-temperature limit.
JOURNAL OF FLUID MECHANICS
(2022)
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, 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)
