Quality of Atomization depends on......

[Mechwill]

This question is specifically focus on siphon air atomizing nozzle, which creates atomization with compressed air. When compressed air enters the nozzle, it creates suction and draws liquid for atomizing process.

Since compressed air is the only driving force for siphoning the fuel and the atomization, it needs to be sized properly. The nozzle we currently use works the best with 15 PSI with 18.4 LPM of air compressor.

In general, for the quality of atomization (size of the atomizing droplets), does it depend on the pressure of compressed air or the volume flow rate of compressed air?

 

[1gibson]

How would you go about separating the two, other than changing nozzle size?

 

[bimr]

Given the design and nature of air atomizing nozzles, flow rates, spray angles and degree of atomization can be affected, and changed by variations within the application. Air velocity and lift will also have an effect on spray angles
and flow rate.

 

[Compositepro]

Higher pressure air creates more fluid shear and turbulence than lower pressure air, and will create smaller droplets.

 

[Mechwill]

To examine the performance of an air compressor for atomization quality, the air compressor which is rated for 15 PSI with 18 LPM is used. For what the compressor is rated, it creates good form of atomization (mistt like). The air output can be controlled by adjusting voltage (DC air compressor). As voltage decreases, the air pressure and flow rate drop accordingly, which the atomization quality becomes very poor (bigger droplet).

By that observation, if the air compressor is switched to a different one which has the same pressure rating but much lower volume flow rate. What would exchange in atomization quality?

Changing nozzle size can solve the problem. Siphon nozzle like this actually is actually selected by the fuel GPM. However, sizing the proper compressor for the nozzle is a different thing.

 

[Compositepro]

If you install a smaller compressor (lower flow rate) it will not produce the pressure you require. The pressure is determined by the resistance to flow of the air nozzle. The compressor determines the air flow rate.

Atomization takes energy. Smaller droplets and greater liquid flow rate require more horsepower. Your air nozzle and liquid nozzle need to be match for the flow rates.

 

[Mechwill]

Compositepro

thank you for the explanation on the relationship between pressure, flow rate and atomization. You were right on the power consumption and the liquid flow rate and droplets.

When I start to spec out the compressors with same voltage and same pressure output, it gives you different flow rate based on the amperage. With this in mind, I can spec out the right compressor. Thanks again