Ignition delay times of H2/O2 mixtures diluted in Ar have been measured behind reflected shock waves with the addition of 02, N2, H2O and CO2 near the second explosion limit.simulations of hydrogen combustion have been performed using a detailed chemical kinetic model, which is composed of 28 elementary reactions. Sensitivity coefficients of each elementary reaction for the ignition delay were calculated. The rate of the reaction of H + 02 + M = HO2 + M is most sensitive to the ignition delay time near the second explosion limit. The effect of additives could attribute to the third body effect in the H + 02 + M reaction. The rate constants for this reaction with various third bodies could be determined by fitting simulation results to the experimental ignition delay times. It is found that the third body efficiencies for H20 and CO2 are much larger than others. These third body effects are extremely important to control ignition and explosion characteristic of hydrogen combustion.
Ar, N2, 02, CO2, およびH20などに希釈した酸素 / 水素混合気体を反射衝撃波により加熱して, 水素の第二爆発限界付近における着火誘導時間を測定した｡ 実験値と, 詳細素反応機構を用いた反応シミュレーションとを比較した｡ 感度解析の結果から, 第二限界付近で着火誘導時間に対してもっとも感度の高い反応は連鎖停止反応H + 02 + M (Mは第三体を表す)であることが確かめられた。 この反応の速度定数をM = Ar, N2, 02, CO2およびH2Oの場合について推定した｡ M=CO2およびH20についての速度定数は他の第三体についての速度定数より大幅に大きいことが見出された。 これらの結果を用いて, 水素の爆発第2限界に対する第一体の添加効果を明らかにした。