Simultaneous Heat and Mass Transfer in Inclined Channel With Asymmetrical Conditions

Abstract

The present work is a numerical study of simultaneous heat and mass transfer with phase change in an inclined channel formed by two parallel plates. The lower one is covered by a thin liquid water film and the upper one is considered impermeable. The plates are maintained at a constant temperature. The liquid film is assumed to be extremely thin and its temperature is uniform and equal to that of the wall. Thermo-physical properties are considered constant and the Boussinesq assumption is adopted. Results show that the effects of the buoyancy forces on the hydrodynamic, thermal and mass fraction fields are important. These effects depend on the channel inclination and may result on flow reversal when the channel approaches the vertical position. This phenomenon is addressed and a flow reversal chart, as well as the corresponding correlations, for different channel inclinations is given. These correlations give the values of Grashof numbers, which induce flow reversal for a given Reynolds number and inclination angle.

Mixed Convection Heat and Mass Transfer with Phase Change and Flow Reversal in Channels

“…6. Axial velocity profiles in the inclined isothermal asymmetrically wetted channel for T 0 = 40°C and φ 0 = 45.5% (Gr T = -1.64 10 5 and Gr M = -10 4 ) (Oulaid et al, 2010d).…”

“…9. Vapour velocity at the lower plate of the isothermal asymmetrically wetted channel for T 0 = 40°C and φ 0 = 45.5% (Gr T = -1.64 10 5 and Gr M = -10 4 ) and different inclination angles (Oulaid et al, 2010d). Figure 10 presents the evolution of the latent Nusselt number (Nu L ) at the wet plate of the isothermal asymmetrically wetted inclined channel.…”

“…The behaviour of Sh resembles to that of Nu S , as Le ≈ 1 here. Sherwood number Sh at the wet plate of the isothermal asymmetrically wetted inclined channel for T 0 = 40°C and φ 0 = 45.5% (Gr T = -1.64 10 5 and Gr M = -10 4 ) and different inclination angles (Oulaid et al, 2010d).…”

“…As heat and mass transfer mixed convection is concerned, such studies are rare as depicted in the introduction. The conditions for the existence of flow reversal was established in the symmetric vertical channel (Oulaid et al, 2010b) and the isothermal asymmetrically wetted inclined channel (Oulaid et al, 2010d). For a given Re we varied T 0 (i.e.…”

Експериментальна Верифікація Методу Визначення Швидкостей У Плівкових Апаратах

“…Система диференційних рівнянь включає рівняння нерозривності та Нав'є-Стокса і описує супутній рух плівки рідини і потоку газу в вертикальному каналі контактного апарату. Однак, даний спосіб не має точного розв'язку і придатний лише для тільки для чисельного розрахунку локальних швидкостей у вертикальному каналі контактного апарату за сумісного руху плівки рідини та газового потоку вниз, або в каналі, розміщеному під кутом [8] за підйомного руху потоку газу.…”