DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
LES of turbulent flow in a concentric annulus with rotating outer wall
要約
The paper reports on large-eddy simulations of fully-developed turbulent flow in a concentric annulus with the outer wall rotating at a range of rotation rates N = Uθ wall / Ub up to 2.8. The flow is defined by the ratio of the inner-to-outer radius, r1 / r2 = 0.5 and the Reynolds number Reh = 12500 based on the hydraulic diameter and the bulk axial velocity. The focus of the study are the effects on the mean flow, turbulence statistics and eddy structure, induced by moderate to very high rotation rates. Similar to a rotating pipe flow, an increase in the rotation rate dampens progressively the turbulence near the rotating outer wall. However, at very high rotations, N = 2.8, instabilities are detected that indicate a trend towards the formation of Taylor-Couettee-type vortex rolls akin to those found between the two counter-rotating cylinders ([3]), which can be regarded as the limiting case of the presently studied flow when N approaches to infinity. In contrast, for moderate rotation rates, i.e. N ≤ 1, the region adjacent to the inner wall is shown to be only marginally affected. However, for N=2 and 2.8 the turbulence parameters and eddy structures differ significantly. These modifications are attributed to the counteracting of the centrifuged turbulence generated near the inner wall and the laminarizing effects of the rotating outer wall permeating towards the inner wall.