Gary C. April

Nonequilibrium Flow and the Kinetics of Chemical Reactions in the Char Zone

Abstract In the temperature range of 500–2500°F, nonequilibrium flow analysis predicted only a small change in pyrolysis gas composition as the gases flow through the char zone. Essentially all of the reactions took place in the temperature range of 2000–2500°F. Comparing nonequilibrium flow with the two limiting cases, the energy absorbed in the char zone for frozen flow was two-thirds that of nonequilibrium flow, and equilibrium flow was about four times that of nonequilibrium flow at the 2500°F level.

Calculation of temperature profile in ablator char using MIMIC.

The differential equation describing the temperature pro file in the carbon zone of a charring ablator was simulated on an IBM 7040 digital computer using MIMIC, a digital- analog simulator language. This differential equation de scribes a nonlinear, two-point boundary value problem, thus requiring an iterative procedure to converge to a solu tion. In order to handle the iterative procedure, the logical- control-variable feature of MIMIC was especially useful.