Study on Gasoline-Air Mixture Deflagration Flame with Different Equivalence Ratios in a Closed Vessel

ABSTRACT

An experimental investigation was carried out on the influence of equivalence ratio on gasoline-air mixture deflagration in a closed vessel. High-speed flame images, flame illuminance, illumination duration, overpressure and reaction produces were recorded for equivalence ratios ranging between the flammable limits. Efforts were made to explore the potential relationships between the visual character presented on the flame images and the deflagration parameters, e.g., the equivalence ratio, the flame duration, and the maximum overpressure. Results show that the gasoline-air mixture presents a smooth spherical flame with lean fuel, a spherical cellular flame with rich fuel, and a curled flocculent flame with very rich fuel. The three flame patterns could be quantitatively identified by calculating the edge pixel amounts and the average b* value (in a Lab color space) of the flame images. The maximum flame illuminance, illumination duration, reaction products, rate of pressure rise, and maximum pressure showed a discriminating value and variation trend versus equivalence ratio under different flame patterns. The rich flame could be considered as the most dangerous flame regime among the three because of its fastest pressure rising speed and highest maximum overpressure. The result is of value to the fundamental research as well as the video-based flame detecting technology.

KEYWORDS:

• Flame character
• Confined space
• Gasoline–air mixture
• Deflagration

Funding

This work was supported by the National youth natural science foundation (No. 51704301) and National defense science and technology project fund (3604031).

Additional information

Funding

This work was supported by the National youth natural science foundation (No. 51704301) and National defense science and technology project fund (3604031).