Calculation orifice expansion valve

[Roberto Cancio]

Dear sirs ,

I have to calculate the diameter of valve oricifio to expasão .
I would like to receive literature from calculus procedure , and hole geometry?

[Brian_UK]

Have a look at Sporlaa documents for selection....
http://sporlanonline.com/literature-and-educational-materials/thermostatic-expansion-valves/

[Roberto Cancio]

Dear Brian ,

Thanks for your help.
Lets try to be more clear in my doubt :
I am working on a development in an a system expansion ( 0 ° C cold chamber ) with fluifo R134a .
The expansion system is composed of an ordinary solenoid valve , an orifice and software superaquecimeto to control the turning on and off the solenoid .
I need to scale the diameter of the bore of the orifice and the orifice is required to obey any geometric shape . Can you help me with this problem ?

[Brian_UK]

Sorry, not my area of expertise.

Seems you are trying to reinvent the wheel.

[PRESS]

It is seldom that you will find someone who wants to go the extra mile of redesingning system components on this forum due to the fact that the manufacturers have reliably given us designed components which otherwise meets common needs. Your best shot is you will get someone who is willing to help you select from what the market offers.

[Roberto Cancio]

Thanks for the help gentlemen ,

I will put a manual expansion valve after the solenoid , selected by the DIRcalc Danfoss .

[PRESS]

Much better option than trying to reinvent things. DIRcalc is a good way to go.

[sterl]

Basic Formula still the same....Is single phase, incompressible fluid, Orifice Equation, which if the Pressure Drop is large so the flow velocity at the orifice much greater than that of the upstream, downstream and any diversions etc. comes to :

m-dot=C Asub O sqrt(2*rho*delta-P)

where m-dot is mass flow
Asub O is the area of the orifice itself...
rho is density
delta-P is pressure difference
C is combined Coefficient of Velocity and Coefficient of Contraction. The usual number is 0.6

See also:

http://en.wikipedia.org/wiki/Orifice_plate

The above equation anlagous to their EQN (2)