High-speed laser visualization of particles thrown by detonation waves

1983 ◽  
Vol 19 (3) ◽  
pp. 363-369 ◽  
Author(s):  
V. M. Boiko ◽  
T. P. Gavrilenko ◽  
V. V. Grigor'ev ◽  
A. A. Karnaukhov ◽  
Yu. A. Nikolaev ◽  
...  
Keyword(s):  
High Speed ◽  
Detonation Waves ◽  
Laser Visualization

scholarly journals Technological advancements in Pulse Detonation Engine Technology in the recent past: A Characterized Report

2019 ◽  
Vol 11 (4) ◽  
pp. 81-92
Author(s):  
Bharat Ankur DOGRA ◽  
Mehakveer SINGH ◽  
Tejinder Kumar JINDAL ◽  
Subhash CHANDER
Keyword(s):  
High Speed ◽  
Combustion Process ◽  
Detonation Waves ◽  
Status Report ◽  
Pulse Detonation Engine ◽  
Operating Cycle ◽  
Air Breathing ◽  
Pulse Detonation ◽  
Pulsed Detonation ◽  
Detonation Engine

Pulse Detonation Engine (PDE), is an emerging and promising propulsive technology all over the world in the past few decades. A pulse detonation engine (PDE) is a type of propulsion system that uses detonation waves to combust the fuel and oxidizer mixture. Theoretically, a PDE can be operate from subsonic to hypersonic flight speeds. Pulsed detonation engines offer many advantages over conventional air-breathing engines and are regarded as potential replacements for air-breathing and rocket propulsion systems, for platforms ranging from subsonic unmanned vehicles, long-range transportation, high-speed vehicles, space launchers to space vehicles. This article highlights the operating cycle of PDE, starting with the fuel-oxidizer mixture, combustion and Deflagration to detonation transition (DDT) followed by purging. PDE combustion process, a unique process, leads to consistent and repeatable detonation waves. This pulsed detonation combustion process causes rapid burning of the fuel-oxidizer mixture, which cannot be seen in any other combustion process as it is a thousand times faster than any other mode of combustion. PDE not only holds the capability of running effectively up to Mach 5 but it also changes the technicalities in space propulsion. The present paper is the extension of the previous study which is also a well characterized status report of PDE in different areas. The present study deals with the categorization of the design approach, computations & simulations, flow visualization, DDT & Thrust enhancement, PDRE’s, experimental detonation engines with some of the experience and research undertaken in Punjab Engineering College under the complete supervision and guidance of Prof. Tejinder Kumar Jindal followed by applications of PDE technology.

Application of a Convolutional Neural Network for Wave Mode Identification in a Rotating Detonation Combustor Using High-Speed Imaging

2020 ◽  
Author(s):  
Kristyn B. Johnson ◽  
Donald H. Ferguson ◽  
Robert S. Tempke ◽  
Andrew C. Nix
Keyword(s):  
Neural Network ◽  
Detonation Wave ◽  
High Speed ◽  
Wave Mode ◽  
Classification Performance ◽  
Detonation Waves ◽  
Single Image ◽  
High Speed Imaging ◽  
Mode Identification ◽  
Rotating Detonation

Abstract Utilizing a neural network, individual down-axis images of combustion waves in a Rotating Detonation Engine (RDE) can be classified according to the number of detonation waves present and their directional behavior. While the ability to identify the number of waves present within individual images might be intuitive, the further classification of wave rotational direction is a result of the detonation wave’s profile, which suggests its angular direction of movement. The application of deep learning is highly adaptive and therefore can be trained for a variety of image collection methods across RDE study platforms. In this study, a supervised approach is employed where a series of manually classified images is provided to a neural network for the purpose of optimizing the classification performance of the network. These images, referred to as the training set, are individually labeled as one of ten modes present in an experimental RDE. Possible classifications include deflagration, clockwise and counterclockwise variants of co-rotational detonation waves with quantities ranging from one to three waves, as well as single, double and triple counter-rotating detonation waves. After training the network, a second set of manually classified images, referred to as the validation set, is used to evaluate the performance of the model. The ability to predict the detonation wave mode in a single image using a trained neural network substantially reduces computational complexity by circumnavigating the need to evaluate the temporal behavior of individual pixels throughout time. Results suggest that while image quality is critical, it is possible to accurately identify the modal behavior of the detonation wave based on only a single image rather than a sequence of images or signal processing. Successful identification of wave behavior using image classification serves as a stepping stone for further machine learning integration in RDE research and comprehensive real-time diagnostics.

Application of a Convolutional Neural Network for Wave Mode Identification in a Rotating Detonation Combustor Using High-Speed Imaging

2021 ◽  
pp. 1-22
Author(s):  
Kristyn B. Johnson ◽  
Donald H. Ferguson ◽  
Robert S. Tempke ◽  
Andrew C. Nix
Keyword(s):  
Neural Network ◽  
Detonation Wave ◽  
High Speed ◽  
Wave Mode ◽  
Classification Performance ◽  
Detonation Waves ◽  
Single Image ◽  
High Speed Imaging ◽  
Mode Identification ◽  
Rotating Detonation

Abstract Utilizing a neural network, individual down-axis images of combustion waves in a Rotating Detonation Engine (RDE) can be classified according to the number of detonation waves present and their directional behavior. While the ability to identify the number of waves present within individual images might be intuitive, the further classification of wave rotational direction is a result of the detonation wave's profile, which suggests its angular direction of movement. The application of deep learning is highly adaptive and therefore can be trained for a variety of image collection methods across RDE study platforms. In this study, a supervised approach is employed where a series of manually classified images is provided to a neural network for the purpose of optimizing the classification performance of the network. These images, referred to as the training set, are individually labeled as one of ten modes present in an experimental RDE. Possible classifications include deflagration, clockwise and counterclockwise variants of corotational detonation waves with quantities ranging from one to three waves, as well as single, double and triple counter-rotating detonation waves. The ability to predict the detonation wave mode in a single image using a trained neural network substantially reduces computational complexity by circumnavigating the need to evaluate the temporal behavior of individual pixels throughout time. Results suggest that while image quality is critical, it is possible to accurately identify the modal behavior of the detonation wave based on only a single image rather than a sequence of images or signal processing.

Numerical Investigation of High-Speed Oxy-Fuel Pulsed Detonation for Direct Power Extraction

2020 ◽  
Author(s):  
Shashank K. Karra ◽  
Sourabh V. Apte
Keyword(s):  
High Speed ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Detonation Waves ◽  
Published Data ◽  
Stoichiometric Ratio ◽  
Direct Power ◽  
Riemann Solvers ◽  
Power Extraction ◽  
Reduced Mechanism

Abstract Oxy-fuel based pulse detonation system can be used for direct power extraction when combined with magnetohydrodynamics (MHD). A space-time conservation element solution element (CE/SE) method is used to investigate the operational envelope of oxy-coal detonations with gaseous methane as a surrogate fuel. The CE/SE method results in a consistent multidimensional formulation for structured/unstructured meshes by providing flux conservation in space and time without the need for complex Riemann solvers to capture solution discontinuities. A modified revised Jones-Lindstedt (JL-R) reaction mechanism accounting for radicals such as O, OH, and H was used as a reduced mechanism to simulate detonation waves from CH4−O2 combustion. The numerical scheme is first verified by comparing predictions with the ZND theory and other published data to show excellent agreement. For shock-induced detonation, the effect of driver shock temperature, pressure, stoichiometric ratio (ϕ) and initial driver shock length, on detonation initiation and propagation was investigated. The simulations accurately predicted detonation velocities, at various ϕ values, compared with available experimental data. The results show that higher gas temperatures and velocities are achieved through oxy-detonations compared to air. The chosen reduced chemical kinetic mechanism, that accounts for radical disassociation, is found to be critical in appropriately limiting heat release during oxy-combustion, thereby predicting detonation temperature and velocity accurately.

Rotating Detonation Instabilities in Hydrogen-Oxygen Mixture

2014 ◽  
Vol 709 ◽  
pp. 56-62 ◽  
Author(s):  
Yu Hui Wang ◽  
Jian Ping Wang
Keyword(s):  
High Speed ◽  
Specific Impulse ◽  
Pressure Sensors ◽  
Intermediate Frequency ◽  
Oxygen Mixture ◽  
Detonation Waves ◽  
Thermodynamic Efficiency ◽  
Detonation Pressure ◽  
Acoustic Oscillations ◽  
Rotating Detonation

Rotating detonation engines are studied more and more widely because of high thermodynamic efficiency and high specific impulse. Rotating detonation of hydrogen and oxygen was achieved in this study. Rotating detonation waves were observed by high speed cameras and detonation pressure traces were recorded by PCB pressure sensors. The velocity of rotating detonation waves is fluctuating during the run. Low frequency detonation instabilities, intermediate frequency detonation instabilities and high frequency detonation instabilities were discovered. They are relevant to unsteady heat release, acoustic oscillations and rotating detonation waves.

scholarly journals Numerical simulation and performances evaluation of the pulse detonation engine

2018 ◽  
Vol 234 ◽  
pp. 01001 ◽  
Author(s):  
Vasile Prisacariu ◽  
Constantin Rotaru ◽  
Ionică Cîrciu ◽  
Mihai Niculescu
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Unmanned Vehicles ◽  
Working Fluid ◽  
Detonation Waves ◽  
Pulse Detonation Engine ◽  
Space Vehicles ◽  
Propulsion Systems ◽  
Pulse Detonation ◽  
Detonation Engine

A pulse detonation engine (PDE) is a type of propulsion system that uses detonation waves to combust the fuel and oxidizer mixture. The engine is pulsed because the mixture must be renewed in the combustor between each detonation wave. Theoretically, a PDE can operate from subsonic up to hypersonic flight speed. Pulsed detonation engines offer many advantages over conventional propulsion systems and are regarded as potential replacements for air breathing and rocket propulsion systems, for platforms ranging from subsonic unmanned vehicles, long range transports, high-speed vehicles, space launchers to space vehicles. The article highlights elements of the current state of the art, but also theoretical and numerical aspects of these types of unconventional engines. This paper presents a numerical simulation of a PDE at h=10000 m with methane as working fluid for stoichiometric combustion, in order to find out the detonation conditions.

scholarly journals Damage Characteristics of Coated Cylindrical Shells Subjected to Underwater Contact Explosion

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Zhi-fan Zhang ◽  
Fu-ren Ming ◽  
A-man Zhang
Keyword(s):  
Cylindrical Shell ◽  
High Speed ◽  
Shear Failure ◽  
Cylindrical Shells ◽  
Outer Shell ◽  
Detonation Waves ◽  
Damage Mode ◽  
Interlayer Water ◽  
Detonation Products ◽  
Damage Characteristics

It is of great significance for the protective design of submarine to study the influences of coverings on the damage characteristics of single and double cylindrical shells subjected to underwater contact explosions. The SPH models of single and double cylindrical shells coated with foam silicone rubber are established to analyze shockwave propagation, damage characteristics, and elastoplastic responses, which provides reasonable parameters of covering position and thickness. The results can be concluded as follows: the superposition of multiple waves may cause the inhomogeneity and discontinuity; for the single cylindrical shell with inner or outer coverings, the damage mode is mainly tensile and shear failure is caused by detonation waves and detonation products; compared with out-covering approach, the in-covering approach has better antishock performance; the best protective effect comes out when the thickness of covering is close to that of the shell; as for the double cylindrical shell without interlayer water, the destruction of inner shell mainly results from the puncture of high-speed fragments from the outer shell, so for the outer shell, out-covering is a better choice; however, since the interlayer water is very effective in protecting the inner shell, in-covering will be better for the inner shell.

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