Need Airflow Analysis on Blower Nozzle

[JCMMSI]

I have a customer that asked me a question I cannot answer. He has a large blower he cleans out feed bunks with in a cattle feedlot. The blower reaches about 180 mph wind speed. His idea is to put a nozzle on the end of the 10" round and go down to a 16" wide x 4" tall rectangle laying flat. I think there will be a lower velocity on the edges of the rectangle at the widest part 14". Since it is going from 9 1/2" I.D. to 14" the air doesn't spread out I wouldn't think. Maybe it would if the volume stays the same? So I thought about placing fins in the inside of the nozzle to direct the air to the edges. However I don't want to take too much from the center and leave it with too low of velocity it doesn't clean out the center of the feed bunk. Can anyone help direct me to an answer to this question? Can you give me an idea what it would cost to have an analysis done to get a solution? I will supply more information to whoever needs it.

Thanks

Jerry Chasek
Mechanical Designer

 

[jelmerra]

Hi Jerry,

Do you have some more information on the geometry?

Jelmer Rouwe
Rouwe Analysis

http://www.rouwe-analysis.info

 

[JKEngineer]

He appears to be reducing the flow area by a significant fraction. (I am having trouble following your dimensions - not sure how a 9.5"ID from a 10"OD, implying 0.25"wall translates to a 16" width becoming a 14" width. )

It is likely that some stratification will occur. It will be affected by the length of the transition, I think. It can be affected by including vanes as you suggest. Part of the problem will be deciding what is the desired exit flow distribution. Given an inlet flow distribution, I think the nozzle can be modeled fairly easily. Lacking the inlet, then the pipe approaching the "inlet" would need to be modeled, perhaps back to the blower and its characteristics. Those comments apply to the nozzle discharging into free air. Discharging when buried in cattle feed is a different order of problem, in my estimation. Would it be buried, or just blowing loose feed in front of it like a leaf blower?

I would be willing to discuss providing the simpler models -- those without the bed of feed burying the nozzle.




Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

http://www.KleinfeldTechnical.com