Validation of predictive performance models for supersonic gas-jet nozzles at the Laboratory for Laser Energetics

K R McMillen; P V Heuer; J M Gjevre; A L Milder; P Charles; T Filkins; H G Rinderknecht; D H Froula; J L Shaw

doi:10.1063/5.0215756

Validation of predictive performance models for supersonic gas-jet nozzles at the Laboratory for Laser Energetics

Rev Sci Instrum. 2024 Jul 1;95(7):073517. doi: 10.1063/5.0215756.

Authors

K R McMillen¹, P V Heuer¹, J M Gjevre², A L Milder¹, P Charles¹, T Filkins¹, H G Rinderknecht¹, D H Froula¹, J L Shaw¹

Affiliations

¹ University of Rochester's Laboratory for Laser Energetics, Rochester, New York 14623, USA.
² University of Alberta, Edmonton, Alberta T6G 2R3, Canada.

PMID: 39016699
DOI: 10.1063/5.0215756

Abstract

We present results characterizing the neutral-density distributions produced by the supersonic nozzles used in experiments on the OMEGA-60 and OMEGA-EP laser systems at the University of Rochester's Laboratory for Laser Energetics (LLE). Axisymmetric Fluent® simulations using LLE nozzle specifications capture the viscous effects, gas expansion, and shock waves that complicate flow predictions for offsets above the nozzle exit. These simulations show good agreement with neutral-density measurements obtained using a four-wave shearing interferometer. An analytical form is given for the plateau length. Fits to simulation data for boundary layer thickness, mean plateau density, and density ramps are given as functions of nozzle offset and nozzle backing pressure for a number of nozzles and gases.