Metering Orifice
To regulate the correct amount of gaseous oxygen entering the combustion chamber we have designed a flat plate metering orifice. The orifice will be choked to insure a consistent mass flow rate through it.
The pressure drop across the rest of the plumbing to the combustion chamber has been estimated at approximately 35psi for our initial static test fire. With a proposed chamber pressure of 500psi this will require us to have an upstream pressure of around 1000psi.
The attached document shows compressible flow calculations used to find orifice diameter.
The flat plate orifice was made from a 0.125" aluminum disk and was placed in line with the oxygen feed system immediately after the check valve.
Calculations for metering orifice
Metering orifice validation (The barrel test)
Motor performance projections for .089" orifice
Attachments: