Experimental investigations of the ignition delay time, initial ignition energy and lower explosion limit of zirconium powder clouds in a 20 L cylindrical vessel

2020 ◽  
Vol 134 ◽  
pp. 429-439
Author(s):  
Xianzhao Song ◽  
Hao Su ◽  
Lifeng Xie ◽  
Bin Li ◽  
Yong Cao ◽  
...  
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Cylindrical Vessel ◽  
Experimental Investigations ◽  
Ignition Energy ◽  
Explosion Limit ◽  
Zirconium Powder

scholarly journals Study on the Ignition Process and Characteristics of the Nitrate Ester Plasticized Polyether Propellant

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xiaoting Yan ◽  
Zhixun Xia ◽  
Liya Huang ◽  
Likun Ma ◽  
Xudong Na ◽  
...  
Keyword(s):  
Grain Size ◽  
Energy Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Temperature ◽  
Ignition Delay Time ◽  
Ignition Process ◽  
Ignition Energy ◽  
Nitrate Ester ◽  
Nepe Propellant

In this study, a CO2 laser ignition experimental system was built to study the ignition process and characteristics of the Nitrate Ester Plasticized Polyether (NEPE) propellant. The effect of the energy density, ingredients, and the grain size distribution of the propellant on the ignition process was investigated using a CO2 laser igniter, a high-speed camera, and a tungsten-rhenium thermocouple. Four types of NEPE propellants were tested under different laser heat fluxes, and the ignition delay time, the ignition temperature, and the ignition energy were obtained. Experimental results show that the ignition process of the NEPE propellant can be divided into three stages, namely the first-gasification stage, the first-flame stage, and the ignition delay stage. When the energy density is lower than the ignition energy threshold, the ignition process cannot be achieved even under continuous energy loading. The increase of the energy density can lead to the decrease of the ignition delay time but has little effect on the ignition temperature. The ingredients and grain size distribution have great effects on both the ignition delay time and the ignition temperature. The grain size effect of aluminum is the largest compared with that of Ammonium Perchlorate (AP) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), while the grain size effect of AP is larger than that of HMX.

A Unified Approach for the Explosion Limits of the Hydrogen-Oxygen System

2017 ◽  
Author(s):  
Alon Lidor ◽  
Daniel Weihs ◽  
Eran Sher
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Sharp Decrease ◽  
Oxygen System ◽  
Explosion Limits ◽  
Proposed Model ◽  
Explosion Limit ◽  
Model Equations ◽  
Fuel Mixtures

We present a new model for the prediction of the explosion limits of the hydrogen-oxygen system. Our model is based on the principle of ignition delay time, postulating that crossing the explosion limit (by increasing the pressure or temperature above it) causes a sharp decrease in the ignition delay time. By using fundamentals of the chain ignition theory, and by employing the Le-Chatelier rule for the explosion limits of fuel mixtures, we develop our model equations. We use numerical analysis to calibrate the constants, and show that our proposed model can accurately capture the unique trend of the peninsula shaped explosion limits. We believe that the relative simplicity of our model will be useful in the analysis of more complex hydrocarbon fuels.

scholarly journals Laminar Burning Velocity and Ignition Delay Time of Oxygenated Biofuel

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3562
Author(s):  
Fekadu Mosisa Wako ◽  
Gianmaria Pio ◽  
Ernesto Salzano
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Burning Velocity ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Complete Characterization ◽  
Experimental Investigations ◽  
Laminar Burning Velocity ◽  
Alternative Sources

The need for lowering the environmental impacts has incentivized the investigation of biomass and biofuels as possible alternative sources for energy supply. Among the others, oxygenated bio-derived molecules such as alcohols, esters, acids, aldehydes, and furans are attractive substances as chemical feedstock and for sustainable energy production. Indeed, the presence of oxygen atoms limits the production of aromatic compounds, improves combustion efficiency (thus heat production) and alleviates the formation of carbon soot. On the other hand, the variability of their composition has represented one of the major challenges for the complete characterization of combustion behaviour. This work gives an overview of the current understanding of the detailed chemical mechanisms, as well as experimental investigations characterizing the combustion process of these species, with an emphasis on the laminar burning velocity and the ignition delay time. From the review, the common intermediates for the most relevant functional groups and combustion of biofuels were identified. The gathered information can be intended for the sake of core mechanism generation.

scholarly journals A study on the influence of ignition energy on ignition delay time and laminar burning velocity of lean methane/air mixture in a constant volume combustion chamber

2021 ◽  
pp. 1-4
Author(s):  
Nguyen Minh Tien Nguyen
Keyword(s):  
Combustion Chamber ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Burning Velocity ◽  
Constant Volume ◽  
Laminar Burning Velocity ◽  
Ignition Energy ◽  
Constant Volume Combustion ◽  
Constant Volume Combustion Chamber

This study presents the effect of ignition energy (Eig) on ignition delay time (tdelay) and uncertainty of laminar burning velocity (Su0) measurement of lean methane/air mixture in a constant volume combustion chamber. The mixture at an equivalence ratio of 0.6 is ignited using a pair of electrodes at the 2-mm spark gap. Eig is measured by integrating the product of voltage V(t) and current I(t) signals during a discharge period. The in-chamber pressure profiles are analyzed using the pressure-rise method to obtain tdelay and Su0. Su0 approximates 8.0 cm/s. Furthermore, the increasing Eig could shorten tdelay, leading to a faster combustion process. However, when Eig is greater than a critical value, called minimum reliable ignition energy (MRIE), the additional elevating Eig has the marginal effect on tdelay and Su0. The existence of MRIE supports to optimize the ignition systems and partly explains why extreme-high Eig>> MRIE has less contribution to engine performance.

scholarly journals Effect of Injection Advance Angle on Auto-Ignition Delay and Response of Ad3.152 Ur Engine

2014 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
Andrzej Ambrozik ◽  
◽  
Tomasz Ambrozik ◽  
Dariusz Kurczyński ◽  
Piotr Łagowski
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Diesel Oil ◽  
Experimental Investigations ◽  
Variable Load ◽  
Response Coefficient ◽  
Auto Ignition ◽  
Load Characteristics ◽  
Load Conditions

The paper presents the results of experimental investigations into the effect of injection advance angle in the AD3.152UR engine on auto-ignition delay time and engine response coefficient value. In the tests, the engine operated under the full load characteristics and was fuelled by commercial diesel oil. The injection advance angle ranged αww<13, 21> CA deg. The tests aimed to assess the engine ability to adapt to variable load conditions.

THERMAL BEHAVIOR AND IGNITION OF HIGH-ENERGY MATERIALS CONTAINING B, ALB2, AND TIB2

2020 ◽  
Author(s):  
A. G. Korotkikh ◽  
◽  
V. A. Arkhipov ◽  
I. V. Sorokin ◽  
E. A. Selikhova ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Flux Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Heat Flux Density ◽  
Ignition Delay Time ◽  
High Energy ◽  
Energy Materials ◽  
High Energy Materials

The paper presents the results of ignition and thermal behavior for samples of high-energy materials (HEM) based on ammonium perchlorate (AP) and ammonium nitrate (AN), active binder and powders of Al, B, AlB2, and TiB2. A CO2 laser with a heat flux density range of 90-200 W/cm2 was used for studies of ignition. The activation energy and characteristics of ignition for the HEM samples were determined. Also, the ignition delay time and the surface temperature of the reaction layer during the heating and ignition for the HEM samples were determined. It was found that the complete replacement of micron-sized aluminum powder by amorphous boron in a HEM sample leads to a considerable decrease in the ignition delay time by a factor of 2.2-2.8 at the same heat flux density due to high chemical activity and the difference in the oxidation mechanisms of boron particles. The use of aluminum diboride in a HEM sample allows one to reduce the ignition delay time of a HEM sample by a factor of 1.7-2.2. The quasi-stationary ignition temperature is the same for the AlB2-based and AlB12-based HEM samples.

Low-Temperature Hypergolic Ignition of 1-Octene with Low Ignition Delay Time

2020 ◽  
Author(s):  
Haoqiang Sheng ◽  
Xiaobin Huang ◽  
Zhijia Chen ◽  
Zhengchuang Zhao ◽  
Hong Liu
Keyword(s):  
Low Temperature ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time

scholarly journals A tangent linear approximation of the ignition delay time. I: Sensitivity to rate parameters

2021 ◽  
Vol 230 ◽  
pp. 111426
Author(s):  
Saja Almohammadi ◽  
Mireille Hantouche ◽  
Olivier P. Le Maître ◽  
Omar M. Knio
Keyword(s):  
Linear Approximation ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time
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