Numerical study of detonation combustion efficiency of gasoline single-component alternative fuel

汽油单组分替代燃料爆震燃烧效率数值研究

School of Power and Energy, Northwestern Polytechnical University, Xi'an 710129, China

Received: 29 July 2024

Abstract

It is difficult to measure the combustion efficiency in the unsteady process of detonation combustion. Therefore, isoctane was used as gasoline single-component alternative fuel and its simplification mechanism was established to numerically simulate the flame acceleration and the DDT process of gaseous gasoline. The gas analysis method was used to study the detonation combustion efficiency under different sampling conditions. The results show that the simplification mechanism model is in good agreement with the combustion characteristics of isooctane within the study range. The numerical study finds that in the detonation combustion process, the concentration of gas components in different regions after detonation wave is quite different and that the combustion near the flame front is not sufficient, thus there being a lot of intermediate products. After detonation wave passes by, the combustion continues. At the same time, the reverse wave may promote the further reaction of combustion and make the combustion more complete. When the equivalent ratio is 1, the average concentration of all gases after detonation wave was taken to calculate the combustion efficiency, which is 82.6%.

摘要

针对爆震燃烧非稳态过程燃烧效率测量困难的问题, 采用异辛烷作为汽油单组分替代燃料, 通过构建异辛烷简化机理对气态汽油的起爆过程进行了数值模拟, 并基于燃气分析法研究了不同取样条件下的爆震燃烧效率。结果表明, 该简化机理模型能够在研究范围内与异辛烷的燃烧特性保持良好的吻合度。经过数值研究发现, 在爆震燃烧的过程中, 爆震波后不同区域内的燃气各组分浓度相差较大, 火焰锋面附近燃烧不充分, 存在大量中间产物, 爆震波经过后可燃物持续燃烧, 同时反传波会促进可燃物进一步反应, 使燃烧更充分。在当量比为1时取爆震波后所有燃气的平均浓度计算得到的燃烧效率为82.6%。