Preparation of a Thermosensitive Gel Dry Water and Its Mechanism for Suppressing Typical Fuel Fires

To enhance the fire extinguishing performance of dry water, this study synthesized a thermosensitive gel dry water extinguishing agent using methyl cellulose as the thermosensitive gel-forming agent, with potassium acetate and aluminum diethylphosphinate as flame retardants via a high-speed stirring method. The physical and chemical properties of the dry water were investigated, along with its effectiveness and mechanism in suppressing pool fires and lithium iron phosphate battery thermal runaway. The results indicated that the gel dry water exhibited optimal fluidity, stability, and moisture retention when the methyl cellulose content was 2 wt% and the potassium acetate content was 3 wt%. The subsequent addition of 7 wt% aluminum diethylphosphinate to this formulation further enhanced the properties of modified dry water, with both the damage rate and water loss rate being significantly lower than those of pure water-based dry water. In fire extinguishing tests, the gel-aluminum salt dry water shortened the extinguishing time for pool fires compared to pure water-based dry water. Although no significant improvement was observed in the cooling rate of the pool fire, the agent demonstrated exceptional performance in suppressing lithium battery thermal runaway. It effectively reduced the battery temperature rebound, which shortened the duration of high temperatures and inhibited the propagation of thermal runaway. Mechanism analysis revealed that the gel-aluminum salt dry water achieves efficient fire suppression through the synergistic effects of cooling, isolation, oxygen dilution, and chemical inhibition. It demonstrates promising application potential for both pool fires and lithium battery fires.