| Water mist fire extinguishing plays a very important role in the fire protection field,and is widely used in computer rooms,archives,ships,subways,high-end hotels,office buildings and other occasions.Water mist fire extinguishing not only effectively suppresses fires,but also requires less water than traditional water sprinklers.It is more environmentally friendly than halon fire extinguishing.Based on the basic design theory of high pressure water mist nozzle,this paper completed the design of a swirling pressure nozzle.Using Fluent fluid simulation software,the distribution of the internal flow field and external mist field of the nozzle was studied in depth.Finally,a preliminary experimental study on the atomization performance of the cyclone pressure nozzle was carried out.The main work done by the thesis is:(1)Based on the analysis of the structure and working principle of the atomizing nozzle,the theoretical research on the swirling pressure nozzle was completed.(2)According to the basic design theory of high-pressure water mist nozzle,the key structural parameters of the nozzle were determined and the design of the single nozzle and the nozzle was completed.The selection of the nozzle material was completed,and the tin bronze QSn7-0.2 with good cutting performance and corrosion resistance was determined as the processing material of the nozzle.The stainless steel was the processing material of the nozzle holder and the fixed bracket,and the rubber was the processing material of the sealing plug.Pressed glass is a processing material for a temperature-sensitive glass column.The strength check of the nozzle body and the temperature-sensitive glass column was completed,and the results showed that the requirements for use were verified,and the rationality of structural design and material selection was verified.(3)The simulation analysis of the nozzle fluid domain was completed usingFluent software.By analyzing the influence of the spray pressure on the nozzle flow rate,it is known that the nozzle flow rate increases as the spray pressure increases,and the flow rate increase rate decreases as the spray pressure increases.The effect of different spray pressures on the atomization effect of the nozzle was analyzed.The results showed that the optimum spray pressure of the nozzle was 8 MPa.By analyzing the influence of the dip angle α of different diversion grooves on the atomization effect of the nozzle,it is determined that the optimal dip angle α of the nozzle is 30°.(4)A preliminary experimental study on the spray performance of the swirling pressure nozzle was completed using the ZTSWB atomizing nozzle.In this paper,the artificial turbine flowmeter,camera and laser particle size measuring instrument are used to conduct preliminary experimental research on the pressure flow characteristics,atomization angle and droplet size and distribution of the nozzle. |
