微通道反应器内氨气的稳燃范围模拟

Simulation Research on the Stable Combustion Range of Ammonia in the Microchannel Reactor

利用Chemkin软件通过基于误差传播的直线关系图法和敏感性分析法简化了氨气燃烧详细反应机理,并利用Fluent软件得出了不同宽度的微通道内氨气与空气的稳燃范围。结果表明:综合误差传播的直线关系图法(DRGEP法)和敏感性分析法得到的65步反应机理与详细机理,在氨气与空气物质的量之比(当量比)为0.2~1.4时的模拟结果吻合较好。氨气在微通道反应器入口段2 mm附近快速燃烧。随着当量比和流速的增加,微通道内混合气体最高温度先增加后减少。随着微通道宽度的增加,氨气稳燃的当量比范围先增加后减小,而稳燃的入口速度范围一直减小,选用较小宽度的微通道结构,能拓宽氨气的稳燃当量比和速度范围,这为氨气在微通道燃烧提供了一定的理论依据。

The CHEMKIN software was used to simplify the detailed reaction mechanism of ammonia combustion through the linear relationship diagram method based on error propagation and the sensitivity analysis method,and the FLUENT software was used to obtain the stable combustion range of ammonia and air in the microchannels with different widths.The results showed that the simulation results according to the 65-step reaction mechanism obtained by combining the DRGEP method and the sensitivity analysis method could be in good agreement with that according to the detailed mechanism,when molar ratio of ammonia to oxygen(NH3/O_(2) ratio)was 0.2-1.4.Ammonia was burned near the entrance of the microchannel reactor within 2 mm.As the NH3/O_(2) ratio and flow rate increased,the maximum temperature of the mixed gas in the microchannel first increased and then decreased.With the increase of microchannel width,the range of ammonia to oxygen ratio required for stable combustion of ammonia first increases and then decreases,and the inlet speed range singly reduced required for stable combustion of ammonia.The smaller microchannel width can broaden the range of NH3/O_(2) ratio and velocity for stable combustion of ammonia,which provides a theoretical basis for the combustion of ammonia in microchannel.