Turbulent flow heat transfer and fluid friction in helical-wire-coil-inserted tubes

✍ Scribed by R. Sethumadhavan; M. Raja Rao

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 816 KB
• Volume: 26
• Category: Article
• ISSN: 0017-9310
• DOI: 10.1016/s0017-9310(83)80154-9

✦ Synopsis

Results are presented from experimental investigations of heat transferin a 25 mm J.D. copper tube, tightly fitted with helical-wire-coil inserts of varying pitch (p), helix angle [x) and wire diameter (e). A similarity law approach was attempted to interpret the friction and heat transfer results and correlate them in terms of roughness Reynolds number (h+), momentum transfer roughness function R(h+) and heat transfer roughness function G(ll+, Prj. The present results are compared with previously published results and a generalized correlation for the G-function has been developed, which is applicable for different types of rough surfaces. An optimization study was made on the basis of maximization of the heat transfer rate and also minimization of pumping power and heat exchanger frontal area to identify the most efficient tube within the matrix of data. lIOO:\IElIOCLATURE A area [m"] C cost [Rs.]