Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
FLOW VISUALIZATION AND NUMERICAL INVESTIGATION OF GAP VORTEX INSTABILITY IN A RECTANGULAR CHANNEL CONTAINING A SINGLE ROD BUNDLE
Submission Author:
Herbert Severino , DF
Co-Authors:
Jhon Goulart, Alexandre Vagtinski de Paula, Herbert Severino
Presenter: Herbert Severino
doi://10.26678/ABCM.COBEM2017.COB17-1137
Abstract
Numerical simulation and flow visualization technique were employed to study the features of the turbulent flow and the large scale structure formation in a closed compound channel. The compound channel is the same geometry that was presented years ago by Guellouz and Tavoularis (2000a) which contains only one rod bundle in a rectangular main channel. However, due to the mas flow rate limitations in our experimental facilities, the Reynolds number was lowered to ReDh = 8000. The Reynolds number, for both numerical and experimental visualization, was computed from the bulk velocity, Ub, the hydraulic-diameter, Dh, and the kinematic viscosity, v. As regards to the numerical methodology finite volumes were applied to discretize the domain along with the URANS k-w SST model to overcome the additional diffusivity caused by the turbulent motion. To shorten the computational domain periodic boundaries in streamwise direction were employed. Flow visualization was carried out by using jet ink technique to visualize the coherent structures formation in a 3 meters long channel. The rod is placed far from the upper channel’s wall by a distance d. The dimensionless distance between the centre of the rod and the nearest channel’s wall, W and the rod diameter, D is W=D - ratio 1.10. Numerical simulation presented good agreement with experimental work from Guellouz, specially for the dynamic of the turbulent flow. As regards the average quantities, these ones showed some discrepancies in comparison with the experimental outcomes published by Guellouz and Tavoularis (2000a). Such discrepancies may be attributed to the Reynolds number difference between both works. In the former work the Reynolds number, based on the same scales from our simulation, is 108000.
Keywords
Flow Visualization, Large scale structure, Rod bundle, SST Model
