激波管中NTC燃料预着火理论分析

Theoretical Study of Pre-ignition of NTC Fuel in Shock Tube

本文针对燃料预着火问题,对文献预着火实验和理论做了梳理,对比激波管中典型NTC燃料DME在不同当量比下着火实验数据。从燃料基础化学特性着手,结合着火延迟期温度微扰动敏感性、热耗散特征以及反应时间尺度特征进行预着火过程理论分析,明晰了温度微扰动敏感性和反应时间尺度特征是预着火发生的主导性因素。研究发现,DME和正庚烷在稀当量比、低压、低燃料浓度时更容易发生预着火。为判断和解析其它燃料预着火现象发生条件和发生机制提供理论参考。

In order to explain the fuel pre-ignition problem,this paper reviews the literature preignition experiment and theory,and compares the ignition experiment data of the typical NTC fuel DME in the shock tube under different equivalence ratios.Focusing on the analysis of the basic chemical characteristics of the fuel,the theoretical analysis of the pre-ignition process combined with the temperature perturbation sensitivity,heat dissipation characteristics and reaction time scale characteristics during the ignition delay time has clarified that the temperature perturbation sensitivity and the reaction time scale characteristics are the dominant factor of pre-ignition occurrence.This study found that DME and n-heptane are more prone to pre-ignition at lean equivalence ratio,low pressure,and low fuel concentration.The research in this paper provides a theoretical reference for judging and analyzing the occurrence conditions and mechanisms of other fuel pre-ignition phenomena.