Laminar flow heat transfer and pressure drop characteristics of power-law fluids inside tubes with varying width twisted tape inserts

Journal Article · Tue Feb 01 04:00:00 EST 2000 · Journal of Heat Transfer

DOI:https://doi.org/10.1115/1.521448· OSTI ID:20067717

Patil, A G

Results of an experimental investigation of heat transfer and flow friction of a generalized power-law fluid in tape generated swirl flow inside a 25.0 mm i.d. circular tube, are presented. In order to reduce excessive pressure drops associated with full width twisted tapes, with less corresponding reduction in heat transfer coefficients, reduced width twisted tapes of widths ranging from 11.0 to 23.8 mm, which are lower than the tube inside diameter are used. Reduced width twisted tape inserts give 18%--56% lower isothermal friction factors than the full width tapes. Uniform wall temperature Nusselt numbers decrease only slightly by 5%--25%, for tape widths of 19.7 and 11.0 mm, respectively. Based on the constant pumping power criterion, the tapes of width 19.7 mm perform more or less like full width tapes. Correlations are presented for isothermal and heating friction factors and Nusselt numbers (under uniform wall temperature condition) for a fully developed laminar swirl flow, which are applicable to full width as well as reduced width twisted tapes, using a modified twist ratio as pitch to width ratio of the tape. The reduced width tapes offer 20%--50% savings in the tape material as compared to the full width tapes.

• Research Organization: Bharti Vidyapith's Coll. of Engineering, Maharashtra (IN)
• OSTI ID: 20067717
• Journal Information: Journal of Heat Transfer, Journal Name: Journal of Heat Transfer Journal Issue: 1 Vol. 122; ISSN 0022-1481; ISSN JHTRAO
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
FLUIDS
FRICTION FACTOR
HEAT EXCHANGERS
HEAT TRANSFER
LAMINAR FLOW
PRESSURE DROP
TUBES
VORTEX FLOW