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.

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.

Experimental Analysis of Wave Propagation in a Methane-Fueled Rotating Detonation Combustor

2018 ◽  
Author(s):  
C. Welch ◽  
D. Depperschmidt ◽  
R. Miller ◽  
J. Tobias ◽  
M. Uddi ◽  
...  
Keyword(s):  
Detonation Wave ◽  
Gas Turbines ◽  
High Speed ◽  
Wave Speed ◽  
Rotation Frequency ◽  
Oblique Shock ◽  
Oblique Shock Wave ◽  
Thermodynamic Efficiency ◽  
Analysis Techniques ◽  
Rotating Detonation

Recently, pressure gain combustion (PGC) has been a subject of intense study because of its potential to increase the thermodynamic efficiency of power generating gas turbines by several percentage points. The rotating detonation combustion/combustor (RDC) can provide large pressure gain within a small volume through rapid heat release by detonation wave(s) that propagate continuously in the circumferential direction. The RDC has been investigated mainly for propulsion applications using hydrogen fuel. In contrast, we present experimental results from an RDC operated on methane and oxygen-enriched air mixtures to represent the reactants in advanced power generating gas turbines. The propagation of detonation and oblique shock waves in the RDC is investigated through High Speed Video (HSV) imaging and Ion Probe (IP) data. HSV imaging requires optical access to the RDC, which can be difficult especially when the RDC is integrated with the gas turbine inlet hardware. Additionally, HSV systems are quite expensive. In contrast, IPs are inexpensive and have the advantages of small size and flexibility in the placement location and can be flush mounted causing minimal interference with the propagating wave. In this study, the detonation wave is tracked by high-resolution HSV imaging at framing rate of 200 kHz. At the same time, IPs are used to detect the rotating oblique shock wave inside the RDC, and different analysis techniques are explored to quantify the wave speed. IP voltage data are analyzed by differentiation, correlation and fast-Fourier transform methods to compute the wave speed (or rotation frequency), and the results are compared with those from the HSV image analysis. The uncertainty of different methods is discussed, and finally, the analysis techniques are applied to investigate the wave characteristics during an experiment.

scholarly journals АНАЛИЗ ХАРАКТЕРИСТИК ТУРБОРЕАКТИВНОГО ДВУХКОНТУРНОГО ДВИГАТЕЛЯ С ФОРСАЖНОЙ КАМЕРОЙ СГОРАНИЯ С ВПРЫСКОМ ВОДЫ ЗА ВХОДНЫМ УСТРОЙСТВОМ

2019 ◽  
pp. 29-38
Author(s):  
Юрий Александрович Улитенко
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Specific Impulse ◽  
Water Injection ◽  
Range Extension ◽  
Thermodynamic Efficiency ◽  
Influence Of Water ◽  
Thrust Characteristics ◽  
New Generation ◽  
Turbojet Bypass Engine

Development of perspective high-speed aircraft inseparably depends on the level of aircraft propulsion engineering as engine performances to determine aircraft capabilities as a whole. The basic requirements to engines of high-speed aircraft are increase speed and flight height. The new generation of turbojet bypass engine with afterburner each their specific thrust and a specific impulse increases, also the application of high technologies raises leads to substantial growth of the engine cost too. At the same time, existing engines design has big reserves for modernization. The system of water injection to the input at the turbojet bypass engine with afterburner is one of the accessible ways for design improvement. Those advanced engines theoretically will allow to satisfy requirements from designers of high-speed aircraft concerning to thrust and other key parameters, at the same time to secure continuity of already existing types of power-plants. The possibility of range extension of turbojet bypass engine with classical scheme afterburner operation till Mach number 3 is considered in this article. The analysis of existing developments is carried out. Impact of water injection to the input at turbojet bypass engine with afterburner on its performance is investigated. Results of calculations for the influence of water injection to reaction mass parameters on the engine duct and its thrust characteristics are proved. Received results will allow to increase thermodynamic efficiency and to expand range extension of turbojet bypass engine with afterburner provided to use materials that applied in aviation manufacture, as well as to reduce terms of development competitive engines for high-speed aircraft at the expense of purposeful search of their rational thermodynamic and is constructive-geometrical architecture.

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.

scholarly journals Numerical Study of Detonation Processes in Rotating Detonation Engine and its Propulsive Performance

2020 ◽  
Vol 2020 (3) ◽  
pp. 30-48
Author(s):  
Tae-Hyeong Yi ◽  
Jing Lou ◽  
Cary Kenny Turangan ◽  
Piotr Wolanski
Keyword(s):  
Numerical Study ◽  
Specific Impulse ◽  
Three Dimensional ◽  
Detonation Waves ◽  
Pulse Detonation ◽  
Propulsive Performance ◽  
Rotating Detonation Engine ◽  
Detonation Engine ◽  
Rectangular Chamber ◽  
Rotating Detonation

AbstractNumerical studies on detonation wave propagation in rotating detonation engine and its propulsive performance with one- and multi-step chemistries of a hydrogen-based mixture are presented. The computational codes were developed based on the three-dimensional Euler equations coupled with source terms that incorporate high-temperature chemical reactions. The governing equations were discretized using Roe scheme-based finite volume method for spatial terms and second-order Runge-Kutta method for temporal terms. One-dimensional detonation simulations with one- and multi-step chemistries of a hydrogen-air mixture were performed to verify the computational codes and chemical mechanisms. In two-dimensional simulations, detonation waves rotating in a rectangular chamber were investigated to understand its flowfield characteristics, where the detailed flowfield structure observed in the experiments was successfully captured. Three-dimensional simulations of two-waved rotating detonation engine with an annular chamber were performed to evaluate its propulsive performance in the form of thrust and specific impulse. It was shown that rotating detonation engine produced constant thrust after the flowfield in the chamber was stabilized, which is a major difference from pulse detonation engine that generates repetitive and intermittent thrust.

HIGH-SPEED IMAGING FOR AN OPTICALLY ACCESSIBLE ROTATING DETONATION ENGINE

2020 ◽  
Author(s):  
Yuhui Wang ◽  
◽  
Jialing Le ◽  
Keyword(s):  
Low Temperature ◽  
Flow Rate ◽  
High Speed ◽  
Equivalence Ratio ◽  
Air Flow ◽  
Detonation Waves ◽  
Outer Diameter ◽  
Air Flow Rate ◽  
High Speed Imaging ◽  
Rotating Detonation

Nonpremixed rotating detonation waves (RDWs) for ethylene or hydrogen and air sources at room temperatures 283-284 K were obtained in the same hollow combustor. The combustor was optically accessible by embedded a piece of quartz glass in the combustor wall. The hollow combustor channel here had an outer diameter 100 mm. Fuel and air were injected into the combustor from 150 cylindrical orifices of a diameter 0.8 mm axially and a circular channel with a width 1 mm radially, respectively. The detonation speeds for ethylene and air were 1562 or 1389 m/s for the air flow rate 642.35 g/s at an equivalence ratio 0.78. The detonation speed for hydrogen and air were 2013 m/s for the air flow rate 327.73 g/s at an equivalence ratio 1.24. Hydrogen operation was more stable than ethylene operation in the condition of low temperature gas sources. High-speed images showed RDW structures were changeful and unstable. Low-temperature regions could intrude into and break the detonation wave.

Investigation of Rotating Detonation Waves in an Annular Gap

2020 ◽  
Vol 310 (1) ◽  
pp. 185-201
Author(s):  
V. A. Levin ◽  
I. S. Manuylovich ◽  
V. V. Markov
Keyword(s):  
Detonation Waves ◽  
Annular Gap ◽  
Rotating Detonation

scholarly journals Part-optimized forming by spatially distributed vaporizing foil actuators

2021 ◽  
Author(s):  
Marlon Hahn ◽  
A. Erman Tekkaya
Keyword(s):  
Process Design ◽  
High Speed ◽  
Specific Impulse ◽  
Design Procedure ◽  
Mathematical Optimization ◽  
Starting Point ◽  
Spatially Distributed ◽  
Lower Tool ◽  
A Minor ◽  
Charging Energy

AbstractElectrically vaporizing foil actuators are employed as an innovative high speed sheet metal forming technology, which has the potential to lower tool costs. To reduce experimental try-outs, a predictive physics-based process design procedure is developed for the first time. It consists of a mathematical optimization utilizing numerical forming simulations followed by analytical computations for the forming-impulse generation through the rapid Joule heating of the foils. The proposed method is demonstrated for an exemplary steel sheet part. The resulting process design provides a part-specific impulse distribution, corresponding parallel actuator geometries, and the pulse generator’s charging energy, so that all process parameters are available before the first experiment. The experimental validation is then performed for the example part. Formed parts indicate that the introduced method yields a good starting point for actual testing, as it only requires adjustments in the form of a minor charging energy augmentation. This was expectable due to the conservative nature of the underlying modeling. The part geometry obtained with the most suitable charging energy is finally compared to the target geometry.

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