scholarly journals IGNITION TIME DELAY OF HYDROGEN-OXYGEN-DILUENT MIXTURES AT HIGH TEMPERATURES

AIAA Journal ◽  
1963 ◽  
Vol 1 (10) ◽  
pp. 2253-2257 ◽  
Author(s):  
J. A. NICHOLLS ◽  
T. C. ADAMSON ◽  
R. B. MORRISON
Keyword(s):  
Time Delay ◽  
High Temperatures ◽  
Ignition Time ◽  
Ignition Time Delay

Numerical Simulation of the Flame Stabilization inside an Aeroderivative Combustor to be Operated with Waste Bio-Gas

2007 ◽  
Vol 23 ◽  
pp. 337-340
Author(s):  
Tudor Prisecaru ◽  
D.C. Dinescu ◽  
L. Mihaescu ◽  
Malina Prisecaru ◽  
G. Darie ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Time Delay ◽  
Ignition Time ◽  
Flame Stabilization ◽  
Gas Composition ◽  
Ignition Time Delay ◽  
Gas Flame

This paper investigates the methods to stabilize a bio-gas flame inside a combustor. A procedure a modelling by dividing the combustor in 8 identical sections, each sections having 343,000 volume cells have been used. Bio-gas composition has been assumed to be 50% methane, 40% carbon dioxide and all the rest to be assimilated with hydrogen in volumetric participation. Due to the different values of ignition time delay, some gas flames already observed to be unstable can be transformed into stable ones by using by-product supplementary fuels

scholarly journals A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chih-Lung Shen ◽  
Jye-Chau Su ◽  
Tsair-Chun Liang
Keyword(s):  
Electric Field ◽  
Electromagnetic Interference ◽  
High Performance ◽  
Ignition Time ◽  
Field Analysis ◽  
The Novel ◽  
Ignition Voltage ◽  
Ignition Time Delay ◽  
Electric Field Analysis ◽  
Faraday Law

A thorough analysis of electric field is carried out so as to verify that a novel dual-electrode plug can build intensive electric field and can improve the main drawbacks of feeble electric field and low ignition efficiency of the traditional plug. With intensive electric field, the proposed novel plug can achieve high performance ignition, resulting in fuel saving and exhaust reduction. Gauss law is applied for electric field analysis to show that intensive electric field can be built by the novel plug. Then, according to Faraday law a lower-voltage ignition feature accomplished by the plug is discussed. Compared with traditional plug, the novel dual-electrode plug has the following advantages. (1) Much higher energy density is built between the plug electrodes, lowering ignition voltage requirement. (2) Electromagnetic interference (EMI) problem caused by high ignition voltage is readily resolved. (3) Ignition time delay can be improved. (4) The feature to save fuel consuming is achieved. (5) The exhaust of CO and HC is reduced significantly. Practical measurements are fulfilled to validate the electric field analysis and to demonstrate the features of the proposed dual-electrode plug.

Experimental and Numerical Analysis of an Ignition Sequence in a Multiple-Injectors Burner

2013 ◽  
Author(s):  
M. Cordier ◽  
A. Vandel ◽  
B. Renou ◽  
G. Cabot ◽  
M. A. Boukhalfa ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Fuel Injection ◽  
Ignition Time ◽  
Ignition Process ◽  
Eddy Simulation ◽  
Ignition Time Delay ◽  
Crucial Information ◽  
Set Up ◽  
The Cost

The design of a gas turbine combustion chamber integrates multiple contradicting objectives. Among all the parameters available to the engineers, the number of fuel injection systems and their spacing are crucial information which need to be fixed early on in the design phase. Indeed, such choices not only impact the cost and size of the combustor but they also affect the operability of the future engine. One key objective behind these parameters is the ignition time delay needed for the whole combustion chamber to successfully light. To gather knowledge in the ignition process that takes place in real gas turbine engines, current research orient towards the development of experimental facilities that complement high fidelity unsteady numerical simulations. In this context, a multi-injectors experimental set-up located at CORIA (France) is used to validate Large Eddy Simulation (LES) tools developed by CERFACS, IFP-EN and CORIA (France). Preliminary validations against experimental data show that for a given inter-injector distance, LES stationary and ignition transient predictions are very promising and recover the main features found in the experiment. Exit mean and root mean square velocity profiles of the steady flow are in good agreement with measurements obtained for all injectors at multiple axial locations. The simulation of the ignition transient phase well captures global events such as the propagation of the flame front from one injector to its neighbors and the related mechanisms. Improvement is however still needed to recover the proper ignition time of the whole burner.

scholarly journals MATHEMATICAL MODELING OF THE METALLIZED SOLID PROPELLANT IGNITION BY A HIGH-TEMPERATURE CONVECTIVE FLOW

2020 ◽  
pp. 126-140
Author(s):  
Poryazov V.A. ◽  
◽  
Krainov A.Yu. ◽  
Keyword(s):  
High Temperature ◽  
Ignition Delay ◽  
Convective Flow ◽  
Solid Propellant ◽  
Ignition Time ◽  
Turbulent Heat ◽  
Combustion Mode ◽  
Stationary Combustion ◽  
Ignition Time Delay ◽  
The Impact

This paper presents a mathematical model and a methodology to calculate stationary combustion of a metallized solid propellant with aluminum additives ignited by a hightemperature convective flow. The study considers the ignition of a semi-infinite slab of the metallized solid propellant which is blown over by an unlimited high-temperature flow. A boundary-layer approximation is used to develop the ignition model. The high-temperature blowing effect is taken into account in the model by means of turbulent heat and mass transfer. The paper provides a numerical and theoretical analysis on the impact of the velocity and temperature of the convective flow on the ignition time delay and the stationary combustion mode establishment. The analysis shows that the proposed approach allows calculating the time of the ignition delay and stationary combustion mode establishment for the metallized solid propellant. Moreover the ignition delay and the period of the stationary combustion mode establishment are found to be controlled by both the velocity and temperature of the convective flow.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

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