Introduction
• What is a sonic orifice?
• How does it work?
• What are its uses?
• How is it applicable to lasers?
Sonic Orifices
• Opening to a cavity
• Reduces flow area to a sonic throat
• Differential pressure and orifice plates (looks like a donut!)
• Determines mass flow rate
Cross-section of an orifice plate
Theory
• Derive equations to determine area of a sonic orifice with input flow parameters
• Observation of the molar flow rate
• Equations can be used for calibrations once an area is determined
Research Methods
• Experimental Set Up
• Predictions
• Experimental Implementation
• Results and Data Analysis
Experimental Set Up
.055in diameterorifice
.040in diameterorifice
Orifice A Orifice B
Experimental Set Up
Nitrogen flowcontrol valves
Micromotion MassFlow Meter
Experimental Set Up
Pressure gauge with.055in diameter orifice
Pressure gauge with.040in diameter orifice
Predictions
• Use area equation to determine theoretical mass flow rate vs. pressure
Experiment
• Run test using Labview and record data
• Check for hysteresis – Record at ascending
pressure– Record at descending
pressure
Labview Diagnostics
ResultsNitrogen Gas through a .0024in2 orifice
y = 0.0009x + 0.0128
y = 0.0009x + 0.013
0
0.02
0.04
0.06
0.08
0.1
0.12
0 20 40 60 80 100
Pressure (psi)
Mo
lar
Flo
w R
ate
(m
ol/s
)
Theoretical Experimental Linear (Theoretical) Linear (Experimental)
ResultsNitrogen Gas through a .0013in2 orifice
y = 0.0004x + 0.0055
y = 0.0005x + 0.0067
0
0.01
0.02
0.03
0.04
0.05
0.06
0 20 40 60 80 100
Pressure (psi)
Mo
lar
Flo
w R
ate
(mo
l/s)
Theoretical Experimental Linear (Experimental) Linear (Theoretical)
Orifices and Hybrid Lasers
• VertiCOIL – What is it?
• Gas Flow and Orifices
• Substantial Effects VertiCOIL Diagram
Review
• Theory is upheld for high mass flow rates
• Useful for VertiCOIL purposes
Acknowledgements
• NASA Illinois Space Grant Consortium
• The Boeing Company
• CU Aerospace
• Darren King and my fellow coworkers at the COIL Lab
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