ISSN Online: 2377-424X
International Heat Transfer Conference 12
Velocity Fields in Stable Rivulets, Following Breakup of Liquid Films Flowing Down a Vertical, Uniformly Heated Wall
要約
The axial and lateral velocity fields in stable, evaporating rivulets, forming following the breakup of a liquid film, flowing down a vertical, uniformly heated wall are investigated. The axial velocity is highest at the mid plane, near the L-V interface, decreases with decreasing distance from the underlying wall, but increases with the wall heat flux and equilibrium contact angle (θ0). Two whirlpools enclosing micro-vortices, form on both sides of the plane of symmetry, surrounded by a region of net up flow near L-V interface and down flow
near the center of the rivulet. The number and size (< 10 μm) of the micro-vortices increase as the wall heat flux increases. At breakup of an evaporating water film having θ0 = 45°, the film thickness at atmospheric pressure increases from ~210 to 350 μm and the number of the micro vortices in a single whirlpool, increases from one to 27, as the wall heat flux increases from 34 and 116 kW/m2, respectively.