Experimental study on the effect of release pressure on the extinguishing efficiency of dry water

The increasingly severe fire situation and the continuous improvement of people's awareness of environmental protection mean that an efficient and environmentally friendly fire extinguishing agent is urgently needed. The appearance of dry water materials provides a new direction for the researchers in the field of fire extinguishing agents. Pressure has a great influence on the core-shell structure of dry water particles. Therefore, the best release pressure will make dry water as fire extinguishing agent to achieve the maximum fire extinguishing efficiency. In this paper, the preparation process of dry water was explored. The characterization results showed that the dry water prepared by the solid liquid ratio of 1:13 with 3000 rpm and 6 min is more consistent with the requirements of fire extinguishing agent. Then the fire extinguishing efficiency of dry water to anhydrous ethanol fire and N-heptane fire under 5 release pressures (0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa) was tested. By comparing the extinguishing time and cooling rate, it is determined that the dry water extinguishing agent can exert the maximum extinguishing efficiency under the release pressure of 0.6–0.7 MPa. Under the release pressure of 0.6 MPa, the extinguishing time of anhydrous ethanol fire is only 0.73 s, and the cooling rate is 9.2 °C/s; Under the release pressure of 0.7 MPa, the extinguishing time of N-heptane fire is only 2.25 s, and the cooling rate is 8.61 °C/s. Finally, the mechanism of dry water fire extinguishing was discussed through the infrared image.