TITLE: HEAT TRANSFER ENHANCEMENT BY A COMBINATION OF SPIRALLY CORRUGATED TUBES WITH A TWISTED TAPES PART 1 - HYDRAULIC RESISTANCE AND HEAT TRANSFER COEFFICIENTS
AUTHOR(S): V. Petkov
ABSTRACT: Heat transfer and isothermal friction pressure drop results have been experimentally obtained
for two single-start spirally corrugated tubes combined with five twisted-tape inserts with different
relative pitches in the range of Reynolds number - . The characteristic parameters of the
tubes are height to diameter ratio, e/Di=0.0371 and 0.0261; pitch to height ratio, p/e=11.6 and 15.9;
and relative pitch, H/Di= 15.68-5.80. Significantly, higher friction factor and inside heat-transfer
coefficients than those of the smooth tube under the same operating conditions have been observed.4
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