mad fridgie
08-02-2010, 03:40 AM
There seems to be a few of these cap. sims. around, so i thought i would have ago my self.
Firstly i have had alook at others (no I do not know code)
I can not find a reference on any to the coiled diameter of the capillary. Surely when you reduce the coiled diameter (like we all do) the physical shape of the round pipe much change. This must effect any simulation program.
Also no allowance for effect of ambient
Then i had a look at the transport properties of the refrigerant (liquid and vapour), these do change slightly acoss the temp and pressure range. (Can sort of handle this one)
Then I came to to phase change in the cap. WOW.
Where i got stumped is not so much the end, but handling this first bubble of vapour. this bubble if I dare call this, varies in its properties, and is dependent upon the down stream, which dependent upon the up stream.
I have given up. i wonder how many of the simulators actally allow for the varing transport properties of the this mixed state. or do they use a expansion constant to give required pressure drop at varing mass flows.
So the question is to what level of accuracy should we be working to +/- ?%
Firstly i have had alook at others (no I do not know code)
I can not find a reference on any to the coiled diameter of the capillary. Surely when you reduce the coiled diameter (like we all do) the physical shape of the round pipe much change. This must effect any simulation program.
Also no allowance for effect of ambient
Then i had a look at the transport properties of the refrigerant (liquid and vapour), these do change slightly acoss the temp and pressure range. (Can sort of handle this one)
Then I came to to phase change in the cap. WOW.
Where i got stumped is not so much the end, but handling this first bubble of vapour. this bubble if I dare call this, varies in its properties, and is dependent upon the down stream, which dependent upon the up stream.
I have given up. i wonder how many of the simulators actally allow for the varing transport properties of the this mixed state. or do they use a expansion constant to give required pressure drop at varing mass flows.
So the question is to what level of accuracy should we be working to +/- ?%