Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Schlieren Studies of the Surface Sub-layers

A cryogenic Schlieren system shown in Fig. 4.5 was used in conjunction with a TV camera and video recorder to observe the convective motion within the surface sub-layer directly. [Pg.55]

A parallel beam of white light from a point source is directed onto a stainless steel mirror submerged 10-30 nun deep in the cryogenic liquid, i.e. sufficiently deep to be clear of both the surface evaporation sub-layer and the radial inflow across the surface of superheated liquid from the wall heated boundary flow. The reflected beam of white light passes out and is focussed on to a viewing screen or camera, after passing a knife-edge to remove the undeviated beam. [Pg.55]

Bearing in mind that the vertical-axis Schheren optics detect horizontal gradients in refractive index, which relate directly to changes in density produced by horizontal gradients in temperature, local convection patterns are revealed in extraordinary detail. [Pg.55]

Combining these findings with the intermittent cold and hot temperature spikes discovered with the fixed micro-thermometers, it is concluded that flie intermittent convection is co-operative in nature. Indeed, the Schlieren pictures show patterns of convection lines which are similar to those observed during extensive studies of the surface evaporation of water by Rayleigh-Benard convection [14,15]. [Pg.57]

In conventional Benard convection [14], flie liquid surface is stationary in the laboratory frame of reference, and hence the cells are stationary, and are observed as a regular array of hexagonal convection or Benard cells. In each cell, hot fluid rises in the centre and cold fluid falls along its boundary (see Fig. 4.7). [Pg.57]


See other pages where Schlieren Studies of the Surface Sub-layers is mentioned: [Pg.55]   


SEARCH



Layered surfaces

Study of surfaces

Sub study

Subbing layers

Surface layers

Surface study

Surfaces studied

© 2024 chempedia.info