(thinking out loud)

 

If one was to have large hoses with low restriction upstream of the cores, and then put restrictors of the same size and shape at the outlet of each of the cores, I wonder if the flows would be close to equal. As long as the most restrictive (highest flow velocity) point is carefully controlled at the exit of the core, I would think that the relative flows could be closely controlled by adjusting the shape & size of each of the restrictors.  As long as the Cores were relatively close in flow-rates I would imagine that the amount of restriction required at the exits would be minimal.

 

Just a theory (anyone care to give it a spin? – or have they already?),

 

Cheers,

Pete

Europa builder and single rotor dreamer.

 

-----Original Message-----
From: Neil Kruiswyk [mailto:neilak@rogers.com]
Sent: Thursday, January 08, 2004 4:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Series vs parralel rads

 

 

 

Ed,

 

            You can put me down for series rads and Jim M as well.  Neither one of us could get the coolant to flow equally through parallel rads.  Jim went so far as to add ball valves on the hot core to try and limit it’s flow.  It worked to a degree but plumbing got very heavy and complicated.

 

            I’ve pondered about this issue and I think there may be a number of factors involved.  (Group input is highly desired)  We both used large hoses for our installations.  1.5” to the Y’s and 1” from the Y’s to the rads.  (Actually, one of us used Y’s and the other T’s).  I’m wondering if the large hoses after the Y was too little flow resistance thereby allowing most of the coolant to pass through one rad.  I notice Tracey uses smaller hoses which may increase flow resistance to each rad and provide more of a balance.  I think someone is using AN16 fittings which is 1” hose but by the time you get through the restrictive male coupling, the same factors may apply.

 

            Al G. may be able to help me with this one…  Assuming a perfect world…  what would the outlet temperature difference be between series rads vs, parallel.  My guess is…  if we had 215 degrees coolant entering the parallel rads and we get 180 degrees leaving the rads, there is a 35 degree drop, or about a 16.3% drop.  Series rads would give a similar % drop divided by 2 for each.  215 – 8% = 199.  Then the second rad sees 199 – 8% = 184  (I rounded off the numbers cuz 1 degree isn’t an issue)  By my calculation (which may be out in left field) the difference is negligible. 

 

Neil  (Giving Rusty something else to think about)