I am trying to determine the exact length of pipe required for my rig design to help effectively mix water droplets with the incoming air flow. For calculation purposes, my water droplet size (MVD) would be around 20 microns and the water content will be around 20g/kg of dry air.
Is there a method of calculation or a standard in BSI/ISO or ASME that deals with this for a straight, cylindrical pipe?
Nice question! can we assume 1D mixing (this is possible if L>>d). In that case, the boundary conditions would be at x=0, C= 20g/kg and at x=L (which is to be determined), dC/dx=0.Now if you write mass conservation equations for water along an element delta_X (considering convection, evaporation and diffusion), I believe the problem can be solved. I would like to know from others whether this approach is correct. Thanks!
Thanks Ramendra Pandey.
I will try and ascertain it from this approach. I have looked into the evaporation rates for water droplets as well but it doesn't yield the required answers.
Just evaporation is not enough. You must include the convection and diffusion terms too since the air as you say is flowing. May be I can help you better if you give me more details about the process. You can separately message me. Thanks!
Thanks Leander Boer
. This approach is good for initial estimations I believe and may yield a general estimation of the pipe length.
While I agree with approach mentioned by Leander Boer
for complete vaporization of liquid droplets along the pipe length, I believe the question concerns about uniform mixing and not complete evaporation. Based on temperature (affecting the time of vaporization), the length of pipe for uniform mixing could be smaller/greater/equal to that required for complete vaporization.- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Atmosphere
- Air