不同化学反应机理对爆震波模拟的影响

Effect of Different Chemical Mechanisms on Simulation of Detonation Waves

采用三阶TVD迎风格式和Strang-splitting算子分裂法以及H-O单步总反应和4种简化反应对爆震燃烧波进行了一维数值模拟,计算结果表明,这5种反应机理都成功起爆并且形成了爆震波.采用单步总反应方程得不到Von-Neumann压力平台区,虽然其Von-Neumann压力峰值与C-J理论最为接近,但是其峰值温度以及爆震波速度过高.采用多步反应机理能很好地捕捉到ZND结构,其爆震波速度与峰值温度能很好地与C-J值一致,采用48反应得到的诱导区长度最小.用CHEMKIN软件计算各化学反应机理得到OH质量分数,采用34反应与CHEMKIN的结果误差最小.采用多步基元反应得到的结果比采用单步总反应所得的爆震波参数更为理想,OH原子团的质量分数可以作为评价化学反应机理是否准确的一个标准.

A traditional upwind scheme with 3-order TVD property and Strang-splitting method are adopted to deal with the simulation of H2/O2/Ar detonation waves. A single step and four reduced chemical mechanisms are simulated by one-dimension code to validate reaction mechanisms in the prediction of detonation quantities. The results show that all of these mechanisms can be used to ignite detonation and lead to the success of self-sustaining the detonation. The flat of pressure and temperature can not be captured by the single step mechanism and the Von-Neumann pressure is proximal compared with the C-J value, but the Von-Neumann temperature is much higher than the C-J temperature. Based on the reduced chemical mechanisms, the ZND structure is obtained, and the pressure and temperature of the Von-Neumann spike are a little lower than C-J value. The induction zones based on the mass concentration of OH are compared and the smallest one is obtained based on the 48-step mechanism. The 34-step mechanism shows the smallest compared error in mass concentration of OH in comparison with CHEMKIN results. All simulation results show that the reduced reaction mechanisms can result in much greater detonation parameters than the single-step mechanism. The mass concentration of OH can be considered as a criterion to estimate the accuracy of chemical mechanisms.