Abstract: Hydrogel fire extinguishing agents can remarkably increase the utilization rate of water and improve fire extinguishing performance in forest fire fighting. At present, there is little research on solid-liquid mixing devices based on hydrogel fire extinguishing agents, and there is a lack of accurate and reliable prediction models. In this study, experiments have been conducted to evaluate the effects of inlet operating conditions and geometric structure on the ejection characteristics of Venturi-type solid-liquid mixer for hydrogel fire extinguishing agents. The results show that the ejection coefficient of the solid-liquid mixer is positively correlated with the inlet velocity of the working fluid. The mixing efficiency of the mixer increases with the increase of the nozzle outlet diameter or the inlet diameter of solid particles. Additionally, the mixing efficiency shows a trend of first increasing and then decreasing with the increase of the working fluid inlet velocity. Based on the experimental results and Buckingham's Π theorem, a prediction model for the ejection characteristics of the solid-liquid mixer for hydrogel fire extinguishing agents is established to provide a theoretical basis for the design of solid-liquid mixing devices based on hydrogel fire extinguishing agents.

Key words: hydrogel fire extinguishing agent, solid-liquid mixer, ejection characteristics, prediction model