采用量子化学计算方法，在低温燃烧条件下对天然气燃烧机理中关键基元反应的活化能进行了计算，用来修正原机理中的活化能数据，以提高天然气机理预测低温点火延迟时间的准确性。在不同工况下（温度900~1 200 K，压力0.5，1，1.5 MPa，当量比0.5，1.0，1.5），对应用广泛的三种天然气详细机理（San Diego 2016，GRI 3.0，Aramco Mech 3.0）进行了对比分析，确定对点火延迟时间预测较准确的Aramco Mech 3.0机理作为研究对象，基于点火延迟时间的敏感性分析，确定敏感性系数最大的基元反应H₂O₂(+M)→2OH(+M)为关键基元反应。运用B3LYP，PM7，M06-2X，CBS-QB3，W1RO五种量化计算方法，对该基元反应的活化能进行了计算；选取了B3LYP，CBS-QB3，W1RO三种方法计算的活化能，更新了原机理中关键基元反应的活化能数据，得到了三种新机理。比较了新机理、原详细机理与闭式均相反应器模型耦合计算得到的点火延迟时间，并与试验值进行了对比分析。结果表明：温度为900~1 200 K时，利用B3LYP方法计算的活化能平均值为212.34 kJ/mol；利用该数据对原机理中的活化能进行修正，修正后的新机理能更准确地预测点火延迟时间，更适用于低温燃烧工况。

The method of quantum chemistry was used to calculate the activation energy of key elementary reactions in the natural gas mechanism under the condition of low temperature combustion, so as to modify the activation energy data in the original mechanism, and therefore improve the accuracy of natural gas mechanism to predict the ignition delay time. Under different working conditions (temperature of 900-1 200 K, pressures of 0.5, 1, 1.5 MPa, equivalent ratios of 0.5, 1.0, 1.5), three widely-used detailed mechanisms (San Diego 2016, GRI 3.0, Aramco Mech 3.0) were compared and analyzed. The Aramco Mech 3.0 mechanism which could predict the ignition delay time accurately was determined as the research object, and the largest sensitivity coefficient of  reaction was identified as the key fundamental reaction based on analysis of the sensitivity of ignition delay time. Five quantitative calculation methods B3LYP, PM7, M06-2X, CBS-QB3 and W1RO were used to calculate the activation energy of fundamental reaction. The activation energies calculated by B3LYP, CBS-QB3 and W1RO were selected, and the activation energies of key elementary reactions in the original mechanism were updated, and three different new mechanisms were hence obtained. The ignition delay time obtained by coupling calculation of the three mechanisms and detailed mechanisms with the closed homogeneous reactor model were compared with the experimental values. The results show that the average activation energy calculated by B3LYP method is 212.34 kJ/mol when the temperature is 900-1 200 K. Using the data to correct the activation energy in the original mechanism, the corrected new mechanism can predict the ignition delay time more accurately, and is more suitable for low-temperature combustion conditions.