Quote:
Originally posted by unregistered
I think you're chasing your tail, treat 'em as black boxes
|
May well be, but I did come up with a better match. (For these three heatercores at least.)
First off, I played around with, "SF Pressure Drop5.0".
The results didn't make sense to me. The software would sometimes calculate negative pressure drops for some features. Quite likely a user problem, but I did come across the following in the FAQ:
"
I have calculated a standard orifice acc. DIN 1952 or EN ISO 5167. The program calculates other pressure drops as I. Why?
The DIN 1952 or EN ISO 5167 calculate the pressure drop direct behind the orifice. These values are used to calculate the flow rate. The program SF Pressure Drop calculates the remain pressure drop which you will find 6 D behind the orifice."
Anyway, I modified my treatment of the flat tubes. My previous go at this, just had a factor based on the length of the tubes.
This time I split that up into a
per tube factor and a
per inch factor. The basis for this, was my dilletante belief, that there should be a pressure drop associated with entering and exiting the flat tube regardless of length, and that there should be a second pressure drop that was dependent on the length of the tubing.
Using these two factors and ignoring the main inlet and outlet altogether gave me the following:
And zoomed in more on the area of interest to most...
The only inputs required to generate these curves is the length of the flat tubes and the number of tubes in each pass.
Reasonably useful general equation for this 'family' of heatercores, or mental masturbation?
I don't know.