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Effect of Wall Friction and Vortex Generation on Radial Void Distribution The Wall - Vortex Effect

Abstract

Arguments are presented to prove the existence of rolling vortices in two-phase flow. In liquid phase they will appear in a boundary layer near the walls while in the continuous vapor phase they will occur near the interface with a liquid film. The intensity and size of these vortices are expected to depend on the local velocity gradients normal to the walls. A discussion is given of the interaction between the rotational field associated with such vortices and bubbles in liquid flow or droplets in vapor-flow. This interaction is called the wall-vortex effect. It appears that several, apparently unrelated, phenomena observed in two-phase flow systems may be interpreted in terms of this mechanism. Among these are: Radial void peaking near the walls; Slip ratios less than unity observed even in vertical upward flow; Reduced droplet diffusion near the liquid film; Reduced vapor mixing between subchannels at low steam qualities; and Accelerated flashing process in flow of depressurized liquid. Finally, a comparison with the well-known Magnus effect is also included
Authors:
Publication Date:
Sep 15, 1974
Product Type:
Technical Report
Report Number:
AE-497
Resource Relation:
Other Information: 22 refs., 10 figs.
Subject:
42 ENGINEERING; VOID FRACTION; WALL EFFECTS; VORTEX FLOW; FRICTION; TWO-PHASE FLOW
OSTI ID:
922504
Research Organizations:
AB Atomenergi, Nykoeping (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
TRN: SE0808049
Availability:
Commercial reproduction prohibited; OSTI as DE00922504
Submitting Site:
SWDN
Size:
3 pages
Announcement Date:
Jan 25, 2008

Citation Formats

Rouhani, Zia. Effect of Wall Friction and Vortex Generation on Radial Void Distribution The Wall - Vortex Effect. Sweden: N. p., 1974. Web.
Rouhani, Zia. Effect of Wall Friction and Vortex Generation on Radial Void Distribution The Wall - Vortex Effect. Sweden.
Rouhani, Zia. 1974. "Effect of Wall Friction and Vortex Generation on Radial Void Distribution The Wall - Vortex Effect." Sweden.
@misc{etde_922504,
title = {Effect of Wall Friction and Vortex Generation on Radial Void Distribution The Wall - Vortex Effect}
author = {Rouhani, Zia}
abstractNote = {Arguments are presented to prove the existence of rolling vortices in two-phase flow. In liquid phase they will appear in a boundary layer near the walls while in the continuous vapor phase they will occur near the interface with a liquid film. The intensity and size of these vortices are expected to depend on the local velocity gradients normal to the walls. A discussion is given of the interaction between the rotational field associated with such vortices and bubbles in liquid flow or droplets in vapor-flow. This interaction is called the wall-vortex effect. It appears that several, apparently unrelated, phenomena observed in two-phase flow systems may be interpreted in terms of this mechanism. Among these are: Radial void peaking near the walls; Slip ratios less than unity observed even in vertical upward flow; Reduced droplet diffusion near the liquid film; Reduced vapor mixing between subchannels at low steam qualities; and Accelerated flashing process in flow of depressurized liquid. Finally, a comparison with the well-known Magnus effect is also included}
place = {Sweden}
year = {1974}
month = {Sep}
}