WANG Dingbiao, DONG Yongshen, XIANG Sa, et al. Performance of double-pipe heat exchanger enhanced by helical fins[J]. CIESC Journal, 2014, (4).
DOI:
WANG Dingbiao, DONG Yongshen, XIANG Sa, et al. Performance of double-pipe heat exchanger enhanced by helical fins[J]. CIESC Journal, 2014, (4).DOI: 10.3969/j.issn.0438-1157.2014.04.008.
Performance of double-pipe heat exchanger enhanced by helical fins
RNG k-ε model is used to simulate the heat transfer of a double-pipe heat exchanger enhanced by helical fins. The simulation results are verified with experimental results. With the Reynolds number from 2362 to 16860
the effect of helix angle α on the Nusselt number and frictional resistance coefficient f are analyzed. The change of performance evaluation criteria(PEC) value and the comprehensive heat transfer performance at the same pump power are examined. The average error of Nu and f are 7.1% and 1.3%
respectively
indicating that the method used is appropriate. For α from 15° to 75°
both Nu and f increase as α decreases. In particular
for α values less than 35°
f increases dramatically as α decreases. With the same pump power
the value of PEC varies from 0.84 to 1.93. In the α range from 15° to 45°
the comprehensive heat transfer performance is better with 35°. Although the PEC values with α of 55°
65° and 75° are slightly higher than that of 35°
Nu is much smaller. Considering the rate of heat transfer in applications
helix angle of 35° is more appropriate
with PEC of 1.26—1.62. Besides
it is proposed to use oblique helical fins to reduce the value of f. Compared with double-pipe heat exchanger enhanced by common helical fins
the Nu value of that enhanced by oblique helical fins with α of 35° and β of 10° is a little higher
f is reduced by 12.5%—14.5%
and PEC varies from 1.38—1.71. The field synergy principle also verifies the result.