面向超燃数值模拟的正癸烷高温骨架机理

A High Temperature Skeletal Mechanism of n-Decane for Numerical Simulation of Supersonic Combustion

关键词:  正癸烷  骨架机理  层流火焰速度  点火延迟时间  熄火拉伸率  反应路径  敏感性分析

Key words:  n-Decane  Skeleton mechanism  Laminar flame speed  Ignition delay time  Extinction strain rates  Reaction paths  Sensitivity analysis

摘要:

为了得到一个适用于超声速燃烧数值模拟的小规模正癸烷骨架机理，以现有的正癸烷燃烧机理（S709）为基础，通过机理简化和参数对比优化的方法，得到了包含27个物种和105个反应的高温骨架机理（S27）。在温度（1000～2000K），压力（0.1～0.3MPa），当量比（Φ：0.5～1.5）的超燃典型工况范围内，通过Chemkin-Pro软件计算了S27对于层流火焰速度、点火延迟时间、熄火拉伸率的预测值，在0.1 MPa富燃条件（Φ=1.7）下，计算了主要物种浓度分布，并与文献正癸烷骨架机理（S40，S96），S709的模拟值和实验数据进行对比，以验证机理的合理性。结果表明S27的计算结果与文献实验数据和S709结果吻合良好。通过研究S27在高温条件下含C物种的反应途径以及影响层流火焰速度的关键反应，进一步证明了S27的合理性。相较于S709及其他正癸烷骨架机理，S27极大地提升了计算速率，展现了此机理应用于超燃流场数值模拟的良好前景。

Abstract:

In order to obtain a small-scale n-decane skeleton mechanism which is suitable for supersonic combustion numerical simulation， based on the existing n-decane combustion mechanism （S709）， a high-temperature skeleton mechanism （S27） including 27 species and 105 reactions was presented by the means of mechanism simplification and parameter optimization. In order to verify the rationality of S27， the predicted values of S27 for laminar flame speed， ignition delay and extinction strain rate were obtained by Chemkin-Pro software package in typical supersonic combustion ranges of temperature （1000～2000 K）， pressure （0.1～0.3 MPa） and equivalence ratio （Φ： 0.5～1.5）， and then compared with experimental data and the predicted values of two other skeleton mechanisms （S40， S96） from literatures and S709. Also， the simulated results of concentration distribution of major species were compared with experimental data at 0.1MPa， rich-fuel condition （Φ=1.7）. The results show that the simulation results of S27 were in good agreement with the experimental data in literature and the predicted values of S709. The study on the main reaction path of carbonaceous components of S27 at high temperature and the key reactions affecting laminar flame speed further proved the reasonability of S27. Compared with S709 and other skeleton mechanisms of n-decane， S27 improves the computation speed significantly， which show the good prospect of applying this mechanism to numerical simulation of combustion flow field of scramjet.