Ignition and Combustion of Pyrotechnic Compositions Based on Microand Nanoparticles of Aluminum Diboride in Air Flow in a Two-Zone Combustion Chamber

2016 ◽  
Keyword(s):  
Combustion Chamber ◽  
Air Flow ◽  
Aluminum Diboride ◽  
Pyrotechnic Compositions ◽  
Ignition And Combustion

Acoustic Diagnostics Applications in the Study of the Oscillation Combustion in Lean Premixed Pre-Evaporation Combustor

2017 ◽  
Author(s):  
Zilai Zhang ◽  
Shusheng Zang ◽  
Bing Ge ◽  
Peifeng Sun
Keyword(s):  
Transition State ◽  
Combustion Chamber ◽  
Acoustic Signal ◽  
Working Condition ◽  
Air Flow ◽  
Thermal Parameters ◽  
Combustion Condition ◽  
Main Frequency ◽  
Pressure Signal ◽  
Lean Premixed

The paper presents an experimental investigation of the thermoacoustic oscillations detection in a lean premixed pre-evaporation (LPP) combustor using acoustic signals. The LPP model combustion chamber oscillation combustion test platform was designed and built, and the combustion chamber oscillation combustion conditions of the sound - pressure - thermal parameters contrast experiment was complete. In this experiment, the thermal parameters signal, the acoustic signal and the dynamic pressure signal were collected under the oscillation state and the transition state (ignition condition, stable to the oscillation combustion condition, the oscillation to the stable combustion condition and the flameout condition), and been analyzed comparatively. The experimental result shows that the acoustic signal and pressure signal can reflect the changing of the main frequency in the combustion chamber. That is, at the same inlet air flow, the main frequency of the combustion chamber is proportional to the thermal load, while at the same fuel flow, the main frequency of the combustion chamber does not change with the changing of air flow. In addition, the frequency multiplication of the acoustic signal is more obvious than the pressure signal’s, which show that the interference of the acoustic signal is less, it can clearly reflect the thermoacoustic oscillation in the combustion chamber. In the transition state, the pulse energy of the acoustic signal is obviously increased after ignition. The main frequency energy increases when the working condition begins to change in the stable to the oscillation combustion condition. The main frequency energy decreases when the working condition begins to change in the oscillation to the stable combustion condition. During the flameout condition, the oscillating energy begins to decay from the high frequency region. For the acoustic signal is less disturbed than the pressure signal and it can obtained the same result with the pressure signal in the oscillation state and the transition state, it can replace the pressure signal in the thermoacoustic coupling oscillation analysis of the lean premixed pre-evaporation combustor the lean premixed pre-evaporation combustor.

scholarly journals CARS and Fluorescent study of ignition of H2/O2 mixtures upon photodissociation of O2 molecular

2018 ◽  
Vol 209 ◽  
pp. 00010
Author(s):  
Vitaly Kobtsev ◽  
Sergey Kostritsa ◽  
Dmitrii Kozlov ◽  
Alexey Pelevkin ◽  
Valery Smirnov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Combustion Chamber ◽  
Test Bench ◽  
Combustion Process ◽  
Kinetic Mechanism ◽  
Uv Laser ◽  
Chain Reactions ◽  
Ignition And Combustion ◽  
193 Nm ◽  
Experimental Test Bench

The research is devoted to gas mixtures ignition by UV laser radiation. The dissociation of O2 molecules by a pulse of excimer ArF laser radiation at 193-nm wavelength with formation of the chemically active oxygen atoms initiating chain reactions which cause ignition of H2/O2 mixture was employed. The experimental test bench was created with CARS and fluorescent techniques for experimental investigation of some peculiarities of mixture ignition and combustion caused by such photo-dissociation, at conditions typical for combustion chamber. Two-dimensional numerical modeling of combustion process in model combustion chamber, based on kinetic mechanism of H2 oxidation including atom O(1P) and radicals OH(A2Σ+), was performed.

The Effect of Fuel Types and Admission Method Upon Combustion Efficiency

1959 ◽  
Vol 81 (4) ◽  
pp. 423-426
Author(s):  
H. N. McManus ◽  
W. E. Ibele ◽  
T. E. Murphy
Keyword(s):  
Combustion Chamber ◽  
Air Flow ◽  
Flow Patterns ◽  
Combustion Efficiency ◽  
Spray Nozzle ◽  
Optimum Size ◽  
Fuel Type ◽  
Chamber Length ◽  
Different Types ◽  
Improved Performance

A series of tests to determine the effect of combustion-chamber length for three different types of fuel admission (gaseous, spray, and vaporized) upon combustion efficiency was performed in identical combustor geometries and with similar air-flow patterns. The effects of fuel-air ratio and full-section velocity were examined for individual methods of admission. The effect of fuel volatility also was examined. It was found that the vaporized fuel type of admission was superior in efficiency to the spray-fuel admission in all comparable cases. Increased fuel volatility improved performance in the case of the vaporizer but did not affect the performance of the spray nozzle. The performance of vaporising tubes was found to vary inversely with size. An optimum size was exhibited.

Actuation Studies for Active Control of Mild Combustion for Gas Turbine Application

2014 ◽  
Author(s):  
Emilien Varea ◽  
Stephan Kruse ◽  
Heinz Pitsch ◽  
Thivaharan Albin ◽  
Dirk Abel
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Active Control ◽  
Gas Turbines ◽  
Reverse Flow ◽  
Air Flow ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Low Oxygen ◽  
Mild Combustion

MILD combustion (Moderate or Intense Low Oxygen Dilution) is a well known technique that can substantially reduce high temperature regions in burners and thereby reduce thermal NOx emissions. This technology has been successfully applied to conventional furnace systems and seems to be an auspicious concept for reducing NOx and CO emissions in stationary gas turbines. To achieve a flameless combustion regime, fast mixing of recirculated burnt gases with fresh air and fuel in the combustion chamber is needed. In the present study, the combustor concept is based on the reverse flow configuration with two concentrically arranged nozzles for fuel and air injections. The present work deals with the active control of MILD combustion for gas turbine applications. For this purpose, a new concept of air flow rate pulsation is introduced. The pulsating unit offers the possibility to vary the inlet pressure conditions with a high degree of freedom: amplitude, frequency and waveform. The influence of air flow pulsation on MILD combustion is analyzed in terms of NOx and CO emissions. Results under atmospheric pressure show a drastic decrease of NOx emissions, up to 55%, when the pulsating unit is active. CO emissions are maintained at a very low level so that flame extinction is not observed. To get more insights into the effects of pulsation on combustion characteristics, velocity fields in cold flow conditions are investigated. Results show a large radial transfer of flow when pulsation is activated, hence enhancing the mixing process. The flame behavior is analyzed by using OH* chemiluminescence. Images show a larger distributed reaction region over the combustion chamber for pulsation conditions, confirming the hypothesis of a better mixing between fresh and burnt gases.

Computational Studies of Glow Plug Ignition of Injected High Pressure Gas Jets

2015 ◽  
Author(s):  
Kang Pan ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Ignition Delay ◽  
Numerical Study ◽  
Pressure Rise ◽  
Air Gap ◽  
Time Difference ◽  
Glow Plug ◽  
Gas Ignition ◽  
Ignition And Combustion

A numerical study of ignition and combustion in a glow plug (GP) assisted direct-injection natural gas (DING) engine is presented in this paper. The glow plug is shielded and the shield design is an important part of the combustion system development. The results simulated by KIVA-3V indicated that the ignition delay (ID) predicted by an in-cylinder pressure rise was different from that based on a temperature rise, attributed to the additional time required to burn more fuel to obtain a detectable pressure rise in the combustion chamber. This time difference for the ignition delay estimation can be 0.5 ms, which is significant relative to an ignition delay value of less than 2 ms. To further evaluate the time difference between the two different methods of ignition delay determination, sensitivity studies were conducted by changing the glow plug temperature, and rotating the glow plug shield opening angle towards the fuel jets. The results indicated that the ID method time difference varied from 0.3 to 0.8 ms for different combustion chamber configurations. In addition, this study also investigated the influences of different glow plug shield parameters on the natural gas ignition and combustion characteristics, by modifying the air gap between the glow plug and its shield, and by changing the shield opening size. The computational results indicated that a bigger air gap inside the shield can delay gas ignition, and a smaller shield opening can block the flame propagation for some specific fuel injection angles.

scholarly journals Parametric study of condensed phase particles interaction with a high-enthalpy air flow in a co-current combustion chamber

2017 ◽  
Author(s):  
А.В. Воронецкий ◽  
◽  
В.И. Смоляга ◽  
К.Ю. Арефьев ◽  
А.А. Гусев ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Condensed Phase ◽  
Parametric Study ◽  
Air Flow ◽  
High Enthalpy

scholarly journals Ignition and combustion of high-energy materials containing aluminum, boron and aluminum diboride

2018 ◽  
Vol 194 ◽  
pp. 01055
Author(s):  
Alexander Korotkikh ◽  
Ivan Sorokin ◽  
Ekaterina Selikhova
Keyword(s):  
Burning Rate ◽  
Ignition Delay ◽  
Delay Time ◽  
Solid Propellant ◽  
Ignition Delay Time ◽  
High Energy ◽  
Solid Propellants ◽  
Amorphous Boron ◽  
Aluminum Diboride ◽  
Ignition And Combustion

Boron and its compounds are among the most promising metal fuel components to be used in solid propellants for solid fuel rocket engine and ramjet engine. Papers studying boron oxidation mostly focus on two areas: oxidation of single particles and powders of boron, as well as boron-containing composite solid propellants. This paper presents the results of an experimental study of the ignition and combustion of the high-energy material samples based on ammonium perchlorate, ammonium nitrate, and an energetic combustible binder. Powders of aluminum, amorphous boron and aluminum diboride, obtained by the SHS method, were used as the metallic fuels. It was found that the use of aluminum diboride in the solid propellant composition makes it possible to reduce the ignition delay time by 1.7–2.2 times and significantly increase the burning rate of the sample (by 4.8 times) as compared to the solid propellant containing aluminum powder. The use of amorphous boron in the solid propellant composition leads to a decrease in the ignition delay time of the sample by a factor of 2.2–2.8 due to high chemical activity and a difference in the oxidation mechanism of boron particles. The burning rate of this sample does not increase significantly.

COHERENT ANTI-STOKES RAMAN SCATTERING AND FLUORESCENT STUDY OF IGNITION AND COMBUSTION OF H2/O2 MIXTURES UPON PHOTODISSOCIATION OF O2 MOLECULES

2020 ◽  
Author(s):  
K. A. Vereshchagin ◽  
◽  
S. Yu. Volkov ◽  
V. D. Kobtsev ◽  
S. A. Kostritsa ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Low Temperature ◽  
Raman Scattering ◽  
Combustion Chamber ◽  
Laser Energy ◽  
Diagnostic Techniques ◽  
Oh Radicals ◽  
Ignition And Combustion ◽  
193 Nm ◽  
Anti Stokes

The low-temperature ignition of H2/O2 mixture promoted by resonant laser radiation leading to the photodissociation of O2 molecules was studied experimentally. The experimental test bench involving the model combustion chamber, coherent anti-Stokes Raman scattering (CARS) and fluorescent diagnostic techniques was created for the experimental investigation of mixture ignition and combustion at conditions typical for gas turbine engines. For the production of chemically active oxygen atoms which initiate ignition in the H2/O2 mixture, the pulsed excimer ArF-laser emitting at a wavelength of 193 nm was employed. Complementary experiments on measuring the temperature and recording the emission of OH and OH* radicals indicate that it is possible to ignite the H2/O2 mixture with ф = 1-3 and P0 = 1-3 atm at a rather low temperature of ~ 700 K under the action of focused laser radiation (A = 193 nm) with the energy in the laser pulse of E = 30-150 mJ. The induction time varies in the range of 8-50 s depending on the laser energy and mixture parameters. Two-dimensional (2D) numerical simulation of ignition and combustion processes in the model combustion chamber was performed. A good agreement of calculation results with experimental data was obtained.

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