The Validity of Velocity Calculations Based on the Plug Flow Assumption in Flow Tube Applications.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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The validity of linear velocity calculations based on the plug flow assumption were tested on flowing argon at 4.2, 5.0, 6.0, and 10.1 torr. The linear velocity of argon was experimentally determined along the centerline of a flow tube, using the argon afterglow technique. It was found that the linear velocity was 1.62 times the plug flow average velocity at a flow rate of 4576.0 standard ccmin and 1.77 times the plug flow velocity at 5262.4 standard ccmin. The velocity data taken at various distances from the centerline revealed a fully developed laminar flow. The velocity results differed from that predicted by the Poiseuille flow formula, and it was determined that this difference was mainly due to obstructions in the argon flow. It was concluded that the plug flow assumption can be used to obtain linear gas velocities in a fully developed laminar flow and approximate gas velocities if the laminar flow is not fully developed. A Stern-Volmer plot was constructed and the results indicated that the 1D - 1S multiplet of Ar V was responsible for the afterglow. Author
- Physical Chemistry