No coin nor oath required. For personal study only.
Consideration of the heat release rate in a fire enables the Froude number to be expressed in terms of the total heat release rate and it is identified by the symbol Q*. This group is widely used in fire problems even when buoyancy effects are negligible, in particular, to correlate dimensionless flame heights. A knowledge of the different regimes of combustion is important and Borghi diagram categorises these in terms of dimensionless groups. The paper shows how ~t can be extended to include the Reynolds and Froude numbers, as well as the Karlovitz stretch factor.
In the field of explosions, it was necessary, historically, to establish scaling laws for the blast damage from solid explosives. This gave rise to the widely used concept of TNT equivalence. Such scaling laws should not be applied to the quite different phenomenon of deflagration. Here, overpressures arise from momentum changes at the flame front and from partial confinement. This necessitates identification of the dimensionless groups that correlate turbulent burning velocities and discussion of the associated scaling laws for overpressures. With controlled venting of vessels a dimensioJ~less group that influences the overpressure depends on the surface area vented and the burning velocity. This enables dimensionless rankings to be made of fuels, in terms of the overpressures that they might generate. The Markstein number has an underlying importance in that it influences flame stability and the effects of flame stretch.
π SIMILAR VOLUMES
The main approaches to estimation of economical consequences of fires have been developed in 70-th. The World Fire Statistics Center that belongs to U.N.O. (United Nations Organization) study problems of fire data collections at world level. However the World Centre of Fire Statistics does not ana
Originals are published in Russian with English translations (from which the following material has been directly reproduced). Articles are published in Russian.