Numerical Study on Flow Structures and Heat Transfer Characteristics of Turbulent Bubbly Upflow in a Vertical Channel

Direct Numerical Simulations of spherical bubbles in vertical turbulent channel flow

“…Lu and Tryggvason (2013) extended their previous studies and simulated a bubble swarm where the background fluid turbulence was increased with respect to the earlier study (Lu and Tryggvason, 2008). Tanaka (2011) performed similar computations of a swarm of nearly spherical bubbles, focusing on the heat transfer mechanism between the two-phase mixture and the walls. In the same configuration, Bolotnov et al (2011) investigated a swarm of nearly spherical bubbles and observed that bubbles tend to rise in the wall region and to increase the production of turbulence.…”

“…to the bubble shape, as investigated by Adoua et al (2009). Numerical simulations (Lu and Tryggvason, 2008;Tanaka, 2011) Turbophoresis Young and Leeming (1997), in the context of particle deposition in turbulent pipe flows, derived the time-averaged particle transport equation in the radial direction…”

“…As a result, a clear separation of flow scales was not possible: small scales influence the large ones and vice versa. Several authors state that neglecting the large scales flow features can have a substantial influence on the results (Tanaka, 2011;Roghair et al, 2011;Dabiri et al, 2013). One of the goals of the present work, therefore, is to address the large-scale flow features generated by the bubbles and to investigate the influence of these on the bubble dynamics.…”

Effects of Bubbles, Droplets or Particles on Heat Transfer in Turbulent Channel Flows

“…the piecewise linear interface calculation (PLIC) method [46]. Aulisa et al [47] developed a Eularian-implicit Lagrangian-explicit (EI-LE) method to improve the advection of F. Tanaka et al [48] carried out DNS on the turbulent upward flow with 12 bubbles by using the non-uniform grid spacing ( x + = z + = 2.08, y + = 0.47 − 2.08) and the PLIC-VOF method. The spatial resolution for the bubble was d p / x = 24.4.…”

Direct numerical simulations of bubbly flows

“…Deen and Kuipers (2013) showed that the passage of a single bubble, or a small group of bubbles, generally increases the local heat transfer. Tanaka (2011) and Dabiri and Tryggvason (2015) examined many bubbles in turbulent channel flows and showed that the bubbles enhances the overall heat transfer, both for nearly spherical bubbles that form wall-layers, as well as for more deformable ones that stay away from the walls. Mass transfer and reactions are in principle relatively simple.…”