Spray Characteristics Of Flow Field For Several Nozzles Based On Simulation Research

Vacuum injection is a new method for preparing a polymer thin film. The traditional method for preparing polymer film presence of residual solvent, holes and susceptible to contamination. Vacuum spray method into film thickness uniformity, smooth and dense, quality has a good application prospect. The structure and spray atomization form of nozzle are the key factor, which determines atomization quality jet flow field, thereby affecting the film quality. This paper reviews the research methods and status of the nozzle, detailing the use of domestic and foreign research jet prepared polymer films and thin film solar cells. This paper studies the impinging pressure atomizer, pressure swirl atomizer and air blast atomizer based jet theory using FLUETN software simulations. The injection process parameter variation trends of the flow field and spray particle atomization of three nozzles are obtained.The impinging nozzle orifice coupled with a gradient of external striker. The smaller the striker diameter, the fewer the obstacle lost; the larger the striker diameter, the greater the obstacle lost. Firing pin diameter, the smaller the area of the firing pin back entrainment speed performance, dynamic pressure, turbulent kinetic energy loss in the amount of entrainment zone the less, the greater the firing pin diameter, the greater the entrainment region, the indicators loss of more large, long distance returned after recovery.A pressure swirl nozzle channel is added swirl chamber and the liquid fully rotate through the swirl chamber through the nozzle exit swirl fully ejected. Different injection conditions greatly affected the spray shape. When the injection pressure is low, a hollow spray cone type, increasing large spray pressure to give a solid cone spray. Under the same conditions of the nozzle diameter, the higher the spray pressure, the smaller the droplet diameter (SMD); the larger the nozzle diameter, the larger the SMD under the same injection pressure.Air blast atomizer using air assisted atomizing medium and jet spray parameters have great influence on the atomization. Different gas-liquid relative velocity has a great effects to the initial SMD value. Small gas-liquid relative velocity, droplet atomization poor quality; large gas-liquid relative velocity, droplet atomization quality has improved significantly. Greater the gas-liquid mass flow ratio (ALR) value, atomization effect is more obvious, smaller the initial droplet size is. When ALR value is greater than 0.20, the initial value with SMD ALR values change only very minor changes. Little effect of different nozzle diameter of the initial SMD. Air blast atomizing nozzle to see the particle distribution of the particle tracking along the axial direction, high gas-liquid relative velocity and large pressure difference inside and outside cause the SMD small amplitude decreases, then the relative speed is reduced due to the gas-liquid two-phase instability weakened dispersion and droplet diameter is large, and the overall diameter of the particles becomes large.