Thermai Theory of Explosion and Ignition

　　Most spontaneous chemical reactions are accompanied by the release of energyand by a tendency to self-heat. Reactions are also sensitive to temperature and reactionrates respond dramatically to temperature increases： a very old empirical rule suggeststhat reaction rates may double for every ten degrees Celsius rise in temperature. Thesetwo considerations underlie the most widespread mechanism known for explosion andfor thermal runaway， and a qualitative understanding of their interplay has existed sincethe days of J.H.van't Hoff.The theory of thermal explosions thus has roots that are about a century old. It isinternational and its modern form begins in France in 1913 with the clear picturesdrawn by C.Taffanel and J.le Floch. These beginnings were repeated in the 1920's bythe man universally acknowledged as the father of modern theories， N. N. Semenov，then working in Leningrad. He and his colleague D. A. Frank-Kamenetskii （1938）inaugurated the modern era and Russian contributions have been continuous andsubstantial to the present day. Around those early years （1930s， 1940s） experimentalstudies of distinction were also undertaken in England and in the United States ofAmerica.These early studies centred on clear but elementary pictures of thermal ignition asthe marginal disappearance of stationary states. De.eper studies of stability， includingquestions of the related study of flame propagation were also being undertaken， and anew strand is woven in the 1950s by chemical reaction engineers concerned with twothemes - exothermic reactions in catalyst pellets， and the behaviour of homogeneoussystems in continuous flow （open systems）. In these decades 1950-1970， manycontributions are made and the last extensive reviews were written then （Merzhanov andDubovitskii; Gray and Lee）. Notable innovative work on non-stationary systems wasdone by Thomas and by Adler.Experiments for a long while lagged behind. A noteworthy direct demonstration ofself-heating and of a critical safe maximum is due to Vanpee （1956）; a full study oftemperature excesses and their dependence on position and time only appears in the late1960s （Gray et al.）. Soon after （1965+） we see the systematic mathematical attacks onthermal explosion theory by Boddington and others， and its linking by B.F.Gray tochain-branching instabilities also begins then.

　　A bout the Author，Professor Feng Changgenwas educated at the BeijingInstitute of Technology（BIT） andat the University of Leeds wherehe took his PhD in PhysicalChemistry.He is Professor ofApplied Chemistry and Vice-President of BIT.He is theauthor of Thermal ExplosionTheory（1988），Thermal IgnitionTheory（1991），and DetonationTheories for Small Size andMicro-channel Explosives119991.as well as numerouspapers in applied chemicalstudies.