The flow of gas–liquid foams through pipe fittings

✍ Scribed by N.S. Deshpande; M. Barigou

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 243 KB
• Volume: 22
• Category: Article
• ISSN: 0142-727X
• DOI: 10.1016/s0142-727x(00)00075-8

✦ Synopsis

Pipe ®ttings introduce complex phenomena in foam structure and ¯ow. The dynamic eects resulting from the interaction of foam with a ®tting are a function of the type of foam generator used and, hence, depend on the initial foam structure. A sudden change in the ¯ow area or ¯ow direction can alter the foam liquid holdup and foam homogeneity, and hence aect ¯ow upstream and downstream of the ®tting. This paper reports a study on the ¯ow of pneumatically generated foams through a variety of pipe ®ttings: pipe bend, pipe elbow, perforated plate and ori®ce plates. The ori®ce plate was the only ¯ow constriction which had negligible eects on the foam ¯ow. Other ®ttings generated large dierences in liquid holdup and pressure gradient between the ¯ows in the upstream and downstream pipe sections. The perforated plate introduced a substantial local pressure drop especially in the case of foams with an initial large polyhedral bubble structure. In such a case, bubble size was also signi®cantly reduced. Foam rheology in the straight pipe sections was successfully described by a power-law model and the friction factor for foam ¯ow could be described by a simple explicit relationship, both in horizontal and vertical ¯ows, regardless of the foam structure and ¯ow regime.