The Physics of Thermo-mechanical Phenomena in Gases

The response of gases to transient, spatially resolved energy addition is quantified mathematically. Non-dimensional describing equations and accompanying parameters are derived and used to characterize the thermo-mechanical physics. The modeling demonstrates that the ratio of the energy addition time scale to the acoustic time scale of the affected volume, and the quantity of energy added to that volume during the former determine the characteristics of the response. Conditions appropriate to classical thermo-acoustics are identified as well as those associated with nearly isobaric and constant volume phenomena. Solutions are presented to describe the consequences of a high activation energy spatially resolved thermal explosion occurring in a reactive gas.