Dust removal characteristics of a supersonic antigravity siphon atomization nozzle

To improve the trapping efficiency of respiratory dust by aerodynamic atomization, reduce the energy consumption and the requirements for the working conditions of nozzles and maintain the health and safety of workers, a comparative experiment evaluating aerodynamic atomization dust removal characteristics was conducted with a self-developed supersonic siphon atomization nozzle, which utilizes a Laval nozzle as the core, and an existing ultrasonic atomization nozzle. The experimental results showed that the new type of nozzle, from the perspectives of droplet speed, conservation of water and pressure, range, and attenuation view, completely surpasses the traditional pneumatic atomization nozzle. A supersonic antigravity siphon atomizer produces a cloud fog curtain composed of high-speed droplets and high-speed air. The particle size of the droplets is less than 10 µ. At the same flow rate of water, its dust removal rate is twice as high as that of ultrasonic nozzles. When the dust removal efficiency is the same, the water consumption of the supersonic siphon atomizer nozzle is 1/2, the air flow rate is 1/3, and the power consumption is 1/2 that of the ultrasonic atomizing nozzles. Siphon atomization can siphon at a total air pressure of 0.2 MPa, and the siphon pressure can reach 0.03 MPa at a total air pressure of 0.4 MPa, which increases with the increase in total inlet air pressure. For the first time, the process of siphoning and nozzle internal atomizing in the field of supersonic atomization dust removal is truly realized. The ultrafine sized droplets with high speeds produced by the new nozzle allow them to cover the limited working space in a shorter time, have a more effective trapping effect for a large number of fine dust particles, and quickly suppress the dust with greater kinetic energy. Therefore, the requirements for the working conditions are reduced, which will save more energy compared to the currently used nozzles available on the market.

Experimental Study and Mechanism Analysis of Effervescent Atomization

The flowand spraycharacteristic of effervescent atomization nozzle has been studied experimentallyandthe inner flow fieldwasanalyzedwithnumerical method. Experiments show that the injection pressure and air/liquid ratio (ALR) are the major factors impacting the atomization stability, and the flow coefficientof the nozzleranged in 0.1-0.15. The VOF simulation of the inner flow field of the nozzle reveals the generaltransformationprocess of the bubble, and the region near the exit orifice plays the dominant roleduringtheatomizationprocesswhere miniature bubbles are generated, expanded in size and accelerated and interacting with the local flow field.

Development of a Swirl Nozzle for Powder Technology

In this study, a gas atomization nozzle for metal powder production has been designed and modeled numerically. The design has been performed in two stages. At the first stage of the design, the size and geometry of the nozzle have been developed to obtain circulated flow through the nozzle as a pre-design. At the second stage, a parametrical analysis has been done using a CFD code. The geometry of the nozzle has been changed and the effect of geometric parameters was determined to find out the more efficient nozzle design parameters. Gas behavior at the nozzle exit and effect of the gas on the melt delivery tube tip has been investigated. Appropriate values for the investigated parameters have been determined to get maximum pressure in vacuum condition at the tip of the melt. The pressure observed at the melt delivery tube was compared with the experimental melt tip pressure data. These results suggest that the CFD solutions can be used in the design of the nozzle. Thus, the lower cost and shorter time would be possible to develop highly efficient nozzle geometry.

The Numerical Simulation on the Atomization Process of Fluid Movement in the Jet Exhausting Atomization Nozzle

The atomization process of liquid droplet is an important stage in the fluid movement process in the jet exhausting atomization nozzle. This stage is directly influenced on the diameter and desperation of water droplet. Today two-dimensional model is often used in the most common simulation framework. But the atomization process in nozzle is usually happened in the three-dimensional model, so the results are not quite agreed with the practice. In this paper, a new three-dimensional model was proposed to study the mechanism of the atomization process. After applying the VOF method and turbulent model in CFD software Fluent, a numerical simulation was performed to analyze the mechanism of atomization process and some related factors affecting the atomization. Results indicated that the shapes of atomization were accorded with experimental investigations. According to the results, the necessity of further characteristic parameters on the atomization process was analyzed.