为了探究NH3/DME混合物的着火特性，利用激波管测量了初始温度T=1 250~1 800 K、当量比Φ=0.5~2.0、DME掺混比XDME=0~1.0、压力p=1 MPa条件下NH3/DME混合物的着火延迟时间。基于测量的试验数据，更新了Issayev等人构建的NH3/DME燃烧反应动力学模型的部分基元反应，更新后的模型表现出对NH3/DME着火延迟时间的良好预测。在此基础上，进一步开展了NH3/DME着火特性值模拟研究。结果表明：NH3/DME高温着火延迟时间随二甲醚（DME）掺混比的增加呈指数降低；NH3/DME的着火延迟时间随当量比的增加先降低后升高，且不同温度下达到最低着火延迟时间的当量比不同；中低温下NH3/DME的着火延迟时间随初始温度的变化规律与高温下不同，呈现出明显的负温度系数(NTC)现象。

To investigate the ignition characteristics of ammonia/dimethyl ether (DME) mixtures, the ignition delay time of NH3/DME blends was measured by using shock tube at T= 1 250-1 800 K, =0.5-2.0, XDME=0-1.0  and p=1 MPa. Based on the measured experimental data, several elementary reactions of NH3/DME combustion reaction kinetics model contructed by Issayev were updated. The updated model showed a good prediction of the ignition delay time of NH3/DME. On this basis, furtherly, the ignition characteristic of NH3/DME blends was numerically studied. The results show that the hightemperature ignition delay time of NH3/DME decreases exponentially with the increase of DME blending ratio; the hightemperature ignition delay time of NH3/DME decreases first and then increases with the increase of equivalence ratio, and the equivalence ratio corresponding to the minimum ignition delay time varies at different temperatures; the variation rule of ignition delay time of NH3/DME at medium and low temperatures with the initial temperature is different from that at high temperature, showing an obvious negative temperature coefficient (NTC) phenomenon.

TK16

湖北省自然科学基金（2022CF845）