Large eddy simulations of 45° inclined dense jets

Abstract

Submerged inclined dense jets (negatively buoyant jets) occur in many engineering applications such as brine discharges from seawater desalination plants and decooling water discharges from liquefied natural gas plants, and their mixing behavior needs to be examined in details for the environmental impact analysis. In the present study, a detailed numerical investigation was performed using the large eddy simulation (LES) approach with both the Smagorinsky and Dynamic Smagorinsky sub-grid scale (SGS) models to simulate the characteristics of the inclined dense jet with 45°inclination. The numerical predictions included the jet trajectory, geometrical characteristics, jet spread and eddy structures. Experimental measurements were also obtained for the validation of the LES predictions, and data from existing studies in the literature were included for comparison. Overall, the LES predictions were able to reproduce the geometric characteristics of the inclined dense jet in a satisfactory manner in most aspects. The dilution was however generally underestimated, which was attributed primarily to the inability of the SGS models to reproduce the convective mixing induced by the buoyancy-induced instability using the adopted grid spacing in the bottom half of the inclined dense jet.

Three-Dimensional Numerical Simulations of Buoyant Jets Discharged from a Rosette-Type Multiport Diffuser

“…Although additional validations may be useful in future works to further demonstrate the performances of the model in modeling rosette inclined buoyant jets, the results are in good accordance with the engineering sense, existing knowledge, and theoretical analysis. Considering that Zhang et al [32] have previously demonstrated the capability of the solver for single jets and Yan and Mohammadian [8] have demonstrated the capability of the solver for multiple inclined dense jets, the present study further indicated that the solver is generally valid for different conditions, so its predictions are believed reliable. However, its performance in modeling other cases, such as rosette buoyant jets in flowing currents, rosette dense jets in stagnant water or flowing currents, jets in stratified conditions, and unequal discharges in stagnant water or flowing currents, requires further validation.…”

“…The present study utilized the multi-fluid solver "twoLiquidMixingFoam" within the framework of OpenFOAM to solve the governing equations. This solver has been validated for single jets by Zhang et al [32] and Yan and Mohammadian [8] for multiple dense jets. However, to the best of the authors' knowledge, it has not been demonstrated to be capable of simulating rosette jets.…”

CFD Modeling of Effluent Discharges: A Review of Past Numerical Studies

“…It is possible that the reason the LRR model works well is that it includes both the slow and rapid pressure terms. OpenFOAM was used to simulate 45° inclined discharges using the LES method and the Smagorinsky and Dynamic Smagorinsky sub-grid scale (SGS) by [26]. This resulted in numerical predictions including geometrical characteristics, the jet trajectory, jet spread, and eddy structures.…”

Experimental and Numerical Investigation of Mixing Phenomena in Double-Tee Junctions

“…This approach models the mixing of two miscible fluids and it can be considered to be an extension of the volume of fluid method [25] with an added diffusion term. The validated OpenFOAM solver twoLiquidMixingFoam [26][27][28] for two incompressible fluids is used and the 3D model is defined as:…”