Flow structure and mass transfer for a wavy channel in transitional flow regime.

Abstract

Literature Cited 1) Akita, K. and F. Yoshida: Ind. Eng. Chem., Process Des. Dev., 13, 84 (1974).2) Cova, D. R.: Ind. Eng. Chem., ProcessDes. Dev., 5, 20 (1966 The relationship between flow structure and mass transfer in a wavy channel was investigated in the range from laminar to turbulent flow. Laminar flow has a steady two-dimensional structure, but turbulent flow has an unsteady three-dimensional vortical structure. In particular, the flow field in a large recirculation vortex within the furrow of a wavywall shows an intermittent reversed flow and a nonuniformity of flow in the spanwise direction for turbulent flow. The flow intermittency is closely related to the mass transfer, and a remarkable increment of mass transfer rate is induced near the flow reattachment point in the large recirculation vortex, which suggests a renewal of the concentration boundary layer because of the flow intermittency.

On the effect of wax content on paraffin wax deposition in a batch oscillatory baffled tube apparatus

“…In addition, the batch OBTA can also be used as a simple test of the performance of wax inhibitors if we first understand the inhibited system. As to the question of how to apply oscillatory motion via oscillating baffles in existing pipelines, similar mixing conditions can be achieved using tubes/pipes with corrugated walls [46,47] at the …”

Heat transfer and pressure drop in furrowed channels with transverse and skewed sinusoidal wavy walls

“…However, the increases of pressure drops from those in plain ducts were even greater than their heat transfer augmentations [2][3][4]. In the quest of further reductions in pressure drop penalties, the sinusoidal wavy channels were developed [5][6][7]. The stable flow recirculation in wavy trough generally developed at low Re.…”

“…In addition to these aforementioned thermal fluid physics in wavy channels, the previous studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] also examined the influences of shifting phase angle (0°, 90°and 180°) between two opposite wavy walls on flow structures [10], the comparative differences between laminar and turbulent wavy channel flows [12], the impacts of channel cross-sectional shape on fluid flow and heat transfer [11] and the effects of interspacing [2,10,14,16] on the furrowed and corrugate channels. Depending on the interspacing between two opposite wavy walls, two different types of transition to turbulence, namely (1) the instability of the shear layer between main flow and recirculation bubbles in the trough of a wavy wall for a narrow channel and (2) the centrifugal instability on the concave surface leading to Taylor-Goertler vortices with a stable three-dimensional form for channels with large interspacing, are reported [16].…”

“…With the thermal fluid analysis available to date for wavy channels, the wall-waves are always normal to the main flow [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. No previous attempt examines the heat transfer and pressure drop in a wavy channel with the main flow skewed to the wall-waves.…”

On the characterisation of wax deposition in an oscillatory baffled device

“…In some of the examples described in the Introduction (e.g., oil transmission lines), the implementation of oscillatory motion via oscillating baffles in existing equipment may be impossible or impractical; however, similar mixing conditions would be achieved using tubes/pipes with corrugated walls 43,44 at the appropriate flow rate of the fluid. Hence an equivalent level of reduction in deposition would be realised.…”