A Numerical Investigation of the Critical Point for Recirculation in Axisymmetric Confined Jets
Date
2021-05-14
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Abstract
The Craya-Curtet number is a similarity parameter used to characterize confined jets. Below the critical Craya-Curtet number, a recirculation zone will exist inside the confined jet. A literature review of confined jets reveals conflicting equations are being used to calculate this number and report experimental results. The different equations are tabulated, assessed and Guiraud's 1991 definition of the Craya-Curtet number is chosen based on appropriate limit behaviour for all diameter ratios and volumetric flow ratios. A numerical validation study for a confined jet is completed using the Large Eddy Simulation (LES) Wall-Adapting Local Eddy-Viscosity (WALE) model and the Reynolds-Averaged Navier-Stokes (RANS) k-ω Shear Stress Transport (SST) model. The RANS k-ω SST model is shown to be sufficient for parametric analysis. To extend on previous studies, numerical simulations are performed to characterize the relationship between the Craya-Curtet number, diameter ratio, and jet Reynolds number. The RANS k-ω SST model predicts a linear relationship between the critical volumetric flow ratio and the diameter ratio. This linear relationship is mapped into the Craya-Curtet number space and the predicted critical Craya-Curtet number increases and approaches a constant as the diameter ratio increases. Conversely, the critical Craya-Curtet number strongly decreases as the diameter ratio approaches one.
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Keywords
Confined Jet, Craya-Curtet, Recirculation, Computational Fluid Dynamics
Citation
Doerksen, G. (2021). A Numerical Investigation of the Critical Point for Recirculation in Axisymmetric Confined Jets (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.