Optimal Structure Designing And Fire Extinguishment Effectiveness Analysis Of The Firefighting Giant

Firefighting giant is the core element of water spray fire control system. the improvement of the performance of the firefighting giant has important practical significance on the reduction of the loss in the fire accident. In this paper, the nozzle jet characteristics of a POK Norman 500 multi-function hoses without recoil has been studied focused on the flow geometry lines and the form of water valve in order to improve the injection velocity and flow rate through the optimization of the nozzle structure by the means of theoretical analysis, numerical simulation and practical test.The main work and conclusions are as follows:(1)Under the guidance of the theories of fire nozzle jet characteristics, the influence of the injection pressure, injection flow rate, the structure of the flow channel and the elevation of water injection on the characteristics of nozzle jet were analyzed and then the optimization of the structure of the firefighting giants was made.The intensity of turbulence and the energy loss were reduced. The performance of nozzle jet and the effect of injection were improved.(2) The three-dimensional physical model of the POK Norman 500multi-function hoses without recoil was Established using software Fluent.nozzle jet characteristics of firefighting giants was simulated by the CFD under the condition of full-open dc injection, full-open spray jet, half-open dc injection and half-opened spray jet respectively. The influence of flow geometry lines and needle valve and ball valve on the intensity of the flow turbulence, energy loss and the stability of the jet flow was revealed. A optimization scheme that cone valve was used instead of ball valve was proposed in order to improve the structure of the channel.(3) The comparison of jet characteristics of firefighting giants between the before and after the optimization showed that the maximum velocity of exit was improved from 16.45m/s to 19.80 m/s, the average velocity was increased from 6.68 m/s to 8.2 m/s, the mass flow rate was enhanced from 11.8 kg/s to 14.5 kg/s, maximum velocity, average velocity and mass flow rate are increased by more than 20% under the conditions of the half-opened spray jet and the maximum velocity of the exit was improved from 17.2 t m/s o 20 m/s, the average velocity was increased from 7.2 m/s to 8.2 m/s, mass flow rate was enhanced from 13 kg/s to 14.8 kg/s, maximum speed, average speed and mass flow rate are increased by more than 13% under the Full-open dc injection.(4)The fire characteristics combined with typical case analysis of super-high, high-level, multi-layer and underground building showed that the jet distance is farther, penetration ability is stronger, the concentration is higher, the water jet area is more extensive after the fire nozzle had been optimized and the adjustment of the mass flow rate and the switch of jet form are convenient. The fire extinguishing efficiency is improved effectively.