对于爆震管中液态辛烷/空气两相混合物的爆燃向爆震转变(DDT)过程进行了数值模拟,建立了对该现象的数学表达,并开发了数值计算程序CTPD。通过数值模拟研究了液态燃料爆震波的基本特性,以及部分预蒸发及液滴数量对于爆震波结构与发展的影响作用。计算结果表明,爆震管中存在一定量预蒸发燃油蒸气有利于促进爆震波的形成,相反,燃油液滴对爆震波的形成则起到一定的抑制作用,液滴数量的增加将会延长由爆燃向爆震转变的过程。研究中计算结果与实验波形符合良好,说明为包括DDT现象在内的脉冲爆震发动机工作过程提供了一种可行的计算方法。
Deflagration to Detonation Transition (DDT) phenomena of liquid fuel octane droplets in air in detonation tube are simulated here. The numerical formulation is described, on which code - CPTD is developed. Basic properties of liquid - fueled detonation structure together with the effects of partial preevaporation and droplet amount on detonation structure and development are investigated in current study. Simulations reveal that the presence of some amount of initial fuel vapor in the tube will substantially expedite transition to detonation, on the other hand, the existence of some fuel droplets may exhibit a suppression to detonation wave, and increasing amount or concentration of fuel droplets will delay deflagration to detonation transition. The calculations show that the numerical results are in good agreement with experimental ones, which implies that a feasible numerical method has been provided here to simulate pulse detonation engine operation processes including DDT phenomena.