The presence of ethanol has an adverse effect on foam spreading

and ethanol fire is difficult to extinguish with aqueous fire-fighting foams. Thus

it is necessary to explore the foam formulation suitable for ethanol fuels and study the spreading behavior of foam over ethanol surface. In the current work

stable foams based on hydrocarbon surfactant (SDS)

fluorocarbon surfactant (FC1157)

and polymers (XG) were prepared by using the compressed-air foam system. The spreading behaviors of foam on polar ethanol and non-polar heptane surface were observed and compared. Furthermore

the effects of stabilizer concentrations

foam flow rates and expansion ratios on foam spreading performance were investigated

respectively. The results indicate that aqueous SDS foam can spread on the heptane layer continuously

but it is difficult to cover the ethanol surface. The addition of XG and FC1157 can synergistically improve the spreading performance of aqueous foam over ethanol. Depending on stabilizer concentrations

there are remarkable differences in foam spreading behaviors. Besides

different foam application parameters including expansion ratios and foam flow rates significantly affect the foam spreading rate

despite the same foam formulation. The research methods and results guide the optimal design of foam formulations as well as the practical application of aqueous foam for ethanol fire extinguishment.