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Calculating the flow of air through the orifice can be done via an iterative process. For any given influent flow rate, influent pipe diameter, orifice diameter and distance of the orifice from the outlet the flow rate of air through the hole can be projected. The value can not be solved for directly because there are too many dependent variables throughout the equations. This dependence can be seen in the list of equations used to model a vertical pipe full of free falling solution that has a hole in the side that is open to the atmosphere. Thus an iterative "guess and check" algorithm was made to solve the system of equations. There are two variations of the program. One calculates the flow rate of air entering the pipe for many different orifice areas until the total orifice area allows so much air in that the pressure inside the pipe equals that of outside the pipe. The other version varies the distance between the outlet of the pipe and the location of the holes until the headloss through that section of pipe equals the distance between the hole and the outlet. This second program takes the orifice size as an input. Both programs can be found >>>>>>>>>>QaOrificeDiffL.xmcd .
Principals used:
Orifice flow
Friction
Reynolds number
Blended density
Blended viscosity
Flow rate
Headloss
Static pressure
Bernoulli's principal
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