Isothermal and heated turbulent upflow in a vertical annular channel – Part II. Numerical simulations

Large eddy simulation of turbulent concentric annular channel flows

“…Figure 6 shows the proÿles of the axial turbulence intensity, i.e. the root-mean-square (rms) value of velocity uctuation, scaled by the averaged friction velocity u deÿned in Equation (13). The peak values of the axial turbulence intensity near the inner wall in Figure 6(a) are higher than those near the outer wall in Figure 6(b) for the same Reynolds number.…”

“…To ensure the axial force balance and to conÿrm that the turbulent ow has reached a fully developed statistic state in terms of Equation (13), the values of local friction velocities at the inner and outer wall and the ratio of the right-and left-hand sides of Equation (13) are listed in Table II velocity at the inner wall is higher than that at the outer wall for the same Reynolds number. Generally, the higher friction velocity results in stronger shear stress at the wall, which thus causes higher turbulence level in the inner wall region.…”

“…Malik and Pletcher [12] examined the performance of some turbulence models on the ow with heat transfer in ducts of annular cross-section. Zarate et al [13] carried out the RANS of isothermal and heated turbulent upward ow in a vertical concentric annular channel with its inner wall heated. Azouz and Shirazi [14] evaluated several RANS models to predict the turbulent ow in concentric annuli and compared their results with the experimental data given by Nouri et al [5].…”

Operation characteristic of Integrated Pressurized Water Reactor under coordination control scheme

“…Many researchers have investigated the heat transfer characteristics of narrow annuli channel (Kang et al, 2001;Zarate et al, 2001;Lu and Wang, 2008), and same researches aiming at the flow distribution of primary side (Zeng et al, 2007;Wei et al, 2011). These related studies indicate that the heat transfer characteristics of narrow annuli are different from conventional channels.…”

Large eddy simulation of turbulent flows in a rotating concentric annular channel

“…Azouz and Shirazi (1998) used RANS technique to calculate the turbulent flow in concentric annuli, and compared their results with the experimental data given by Nouri et al (1993). Zarate et al (2001) carried out numerical simulation with RANS method on the isothermal and heated turbulent upflow in a vertical concentric annular channel, with its inner wall heated. Recently, Chung et al (2002) performed a direct numerical simulation (DNS) on turbulent annular channel flow at low Reynolds number.…”