Study on the atomization characteristics of gel by liquid carbon dioxide

Abstract

Super absorbent polymer (SAP) gel materials have emerged as a focal point of research in the firefighting domain, owing to their remarkable water retention capabilities and inherent flexibility. However, due to the high viscosity of the gel material, it is usually treated with a medium atomization method. Liquid CO₂ has a very high expansion coefficient, and when released, it can effectively drive away oxygen in the fire area. With the development of carbon capture and utilization (CCU) technology, more and more CO₂ being stored in liquid form in cylinders, making it meaningful to explore using liquid CO₂ as a medium for atomizing the gel. This paper proposes using the liquid CO₂ as the atomization medium and designs a hybrid atomization system. The system utilizes the large amount of energy released when liquid carbon dioxide turns into gas, thereby enhancing the atomization effect for high-viscosity fluids and helping to carry out carbon capture and utilization (CCU) work simultaneously. The influences of the inlet diameter of liquid CO₂ (d₀), the number of outlet holes of mixed liquid (N_holes), and the gel concentration (C) on the atomization characteristics of the gel jet were investigated. The research results indicate that with an increase in d₀, the spray range, spray width, and spray cone angle increase correspondingly, while the spray particle sizes D₃₂ and Dv90 decrease accordingly. With an increase in N_holes, the spray range and the particle sizes D₃₂ and Dv90 show an increasing trend, while the spray cone angle and spray width decrease correspondingly. As the gel concentration increases, the spray range, spray width, and spray cone angle decrease, while the particle sizes D₃₂ and Dv90 increase accordingly.