With the development of the plateau environment, to make better use of the heat energy and safety of combustion devices, the structure and stability evaluation of horizontal jet flame and other related issues have attracted more and more people's attention. Consecutive image processing of flame is one of the emerging methods to evaluate the flame structure. In this paper, the statistical invariance of horizontal spray flame under low pressure is investigated experimentally and photographically, especially the characteristic of flame terminal fluctuation. A consecutive flame image of 0.05 MPa atmospheric pressure taken by conventional 25 frames per second in a low-pressure chamber was processed with probabilistic statistics, and the probability statistical contours were obtained by binarization statistics for the consecutive 100 to 1000 frames. The results show that different flame characteristic parameters have a different minimum statistical threshold, but most of them are between 300 and 400. The most reasonable statistical interval is determined by combining it with the flame stability evaluation index. The variation mechanism and feasibility of using statistical invariance to characterize flame stability are illustrated from the viewpoint of flame fluctuation characteristics. This is of great significance to the integrity of probabilistic processing of horizontal jet flame and lays a theoretical foundation for flame stability evaluation.

随着高原环境的发展，为更好地利用热能和燃烧装置的安全性，水平喷射火焰的结构及稳定性评价等相关问题越来越受到人们的关注。火焰连续图像处理是评价火焰结构的新兴方法之一。本文对低压下水平喷射火焰的统计不变性进行了实验和摄影研究，特别是火焰末端波动的特性。对低压室内常规每秒25帧拍摄的0.05 MPa大气压连续火焰图像进行概率统计处理，对连续100～1000帧进行二值化统计得到概率统计轮廓。结果表明，不同的火焰特征参数具有不同的最小统计阈值，但大多在300~400之间，结合火焰稳定性评价指标确定最合理的统计区间。从火焰波动特性的角度阐述了用统计不变性表征火焰稳定性的变化机理和可行性。这对水平喷射火焰概率处理的完整性具有重要意义，为火焰稳定性评价奠定了理论基础。结合火焰稳定性评价指标确定最合理的统计区间。从火焰波动特性的角度阐述了用统计不变性表征火焰稳定性的变化机理和可行性。这对水平喷射火焰概率处理的完整性具有重要意义，为火焰稳定性评价奠定了理论基础。结合火焰稳定性评价指标确定最合理的统计区间。从火焰波动特性的角度阐述了用统计不变性表征火焰稳定性的变化机理和可行性。这对水平喷射火焰概率处理的完整性具有重要意义，为火焰稳定性评价奠定了理论基础。