Numerical analysis on deflagration-to-detonation transition of a hydrogen-oxygen mixture in a smooth tube

Inaba, Yoshitomo  ; Kotchourko, A.*; Breitung, W.*

The Flow and Combustion Engineering Division at the Forschungszentrum Karlsruhe carried out the explosion experiments of hydrogen-oxygen mixtures in a smooth tube made of stainless steel after two radiolysis gas explosion accidents occurred in Japanese and German BWRs. In these experiments, stoichiometric hydrogen-oxygen mixtures with different initial pressures were used. The pressure in the tube and the strain of the tube were measured, and then the structural response during the detonation and the Deflagration-to-Detonation Transition (DDT) process were investigated. In the present study, a numerical analysis was performed to simulate one of the experiments by the use of the 3-dimensional turbulent combustion analysis code COM3D, which has been developed in FZK, and a DDT process was calculated. The COM3D code contains a reaction rate constant, which must be obtained empirically from experimental results. In the present calculation, the reaction rate constant was assumed to be an exponential function. As a result, it was found that the COM3D code can simulate the DDT process.