Ignition of Solids

Step 1 The solid is heated, raising its temperature to produce pyrolysis products that contain gaseous fuel. This decomposition to produce gaseous fuel can be idealized by an Arrhenius type reaction 

Fundamentals of Fire Phenomena James G. Quintiere 2006 John Wiley Sons, Ltd ISBN 0 470 09113 4 

Let us just consider the piloted ignition case. Then, at Tpy a sufficient fuel mass flux is released at the surface. Under typical fire conditions, the fuel vapor will diffuse by turbulent natural convection to meet incoming air within the boundary layer. This will take some increment of time to reach the pilot, whereby the surface temperature has continued to rise. 

Step 3 Once the flammable mixture is at the pilot, there will be another moment in time for the chemical reaction to proceed to thermal runaway or a flaming condition. 

This three-step process can allow us to express the time for ignition as the sum of all three steps [2]  

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M, Barrere, RechAerosp No 123, 15—28 (1968) CA 70, 69707 (1969) Static and dynamic methods for studying the ignition of solid-propint rockets are described. The principal parameters affecting the ignition are the... 

In the nineteenth century, Humphry Davy (1778-1829) speculated that the luminosity of flames is caused by fhe production and ignition of solid particles of carbon as a resulf of the decomposition of a part of the gas. Jons Jakob Berzelius (1779-1848) is said to be the first to describe an ordinary candle flame as consisting of four disfincf zones. Davy s protege, Michael Faraday [9] (1791-1867) gave his Christmas lectures and accom-pan3ung demonstrations to a juvenile audience on "The Chemical History of a Candle" in 1848 and 1860. Around the turn of the century, modem combustion science was established based on the increased understanding of chemistry, physics, and thermodynamics. 

Factors that can contribute to the spontaneous ignition of solids are many ... 

List three properties or parameters that play a significant role in causing spontaneous ignition of solid commodities. 

The time for ignition of solid fuels is principally controlled by... 

We will develop an analytical formulation of the statement in Equation (8.2). This will be done for surface flame spread on solids, but it can be used more generally [1], As with the ignition of solids, it will be useful to consider the limiting cases of thermally thin and thermally thick solids. In practice, these solutions will be adequate for first-order approximations. However, the model will not consider any effects due to... 

T. Sakai, "Ignition of Solid Propellants by Periodic Heating with Special Reference to Instability in Solid Propellant Rockets , Ibid, pp 873-86 Ij) M. Barr re J.J. 

The rocket consists of a rocket motor (which also acts as a combustion chamber on ignition of solid propellant) with a nozzle on one end and an ignition device on the other end. (Figure 1.4)... 

P.H. Thomas and P.C. Bowes. Some aspects of the self-heating and ignition of solid cellulosic materials. British Journal of Applied Physics, 12 222-229, 1961. 

MATERIAL PARAMETERS CONTROLLING THE IGNITION OF SOLID FUELS 3.4.1 Spontaneous Ignition... 

Thomson, H.E., Drysdale, D.D., and Beyler, C.L., An experimental evaluation of critical surface temperature as a criterion for piloted ignition of solid fuels, Fire Safety Journal, 13, 185-196, 1988. 

In the context of fire CFD, it is sometimes appropriate to distinguish between flame and fire spread simulations. Flame spread simulation usually means the ability to predict the fire growth starting from a small initial fire or ignition point, where all the three subprocesses are important but the second subprocess dominates the heat transfer. Fire spread, in turn, means the ignition of solid surfaces in the presence of a relatively large initial fire dominating the heat transfer by radiation. In practice,... 

Ammonium perchlorate has been studied quite often in recent times because it is used for solid rocket fuel(H.Osada and E.Sakamoto Thermal decomposition of ammonium perchlorate, J.Exp.Soc.,JapanNo.5, P 236 (1963) H.Osada and S.Kakinouchi Initiation of the ignition of solid composite propellant, No., p.290(1965)) It is thought that there are two kinds of decomposition the first occurs below 300 0, and the other over 300 0. The reactions seem to be different from each other. They are very complicated and the products are detected as N iO, N i, NO, NO., NHj, HCIO, HNO3, HCl, HNOj, 0. ... 

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