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dyf_1
13-11-2004, 03:22 PM
hi

could you tell me how to choice a tub cube for R23 in a cascade system, thanks

Peter_1
14-11-2004, 10:26 AM
Wha is a tub cube?
Do you mean capillary tube?

Peter

dyf_1
15-11-2004, 03:14 AM
sorry, My mean is capillary tube

Peter_1
15-11-2004, 07:54 AM
There may exists software programs for this and there exists even formulas for this (Stoecker for example has them in his book Refr & AC) but we did it with trail and error. (We hadn't these formulas in the past)
Started with the cap tube tables we got from R502 with +/- the same pressure drop and cut the capillary somewhat longer. Installed a shutoff valve before the cap tube and a schraeder on the evaporator so that we could retract the gas and evacuate after each trial.
In the formulas, you need certain numbers like Friction factor, Reynolds number, fraction of vapor mixture of liquid and vapor, viscosity of saturated liquid and saturated vapor,... in my opinion, not that easy to find.
It takes +/- 3 pages of formula's in his book.