TY - GEN
T1 - Experimental study of thermal performance and flow behaviour with winglets vortex generators in a circular tube
AU - Nurizki, A.
AU - Islam, Md
AU - Alam, Md
N1 - Funding Information:
This work was supported by the Khalifa University of Science & Technology, The Petroleum Institute, Abu Dhabi, UAE. This support is gratefully acknowledged.
Publisher Copyright:
Copyright © 2019 ASME
PY - 2019
Y1 - 2019
N2 - Vortex generator (VG) is one of the passive techniques which could improve the heat transfer with relatively low pressure drop. Vortex generators create streamwise longitudinal vortices which does not decay until far downstream that leads to have higher heat transfer with a lower pressure drop. The objectives of this experiment were to study the heat transfer and flow characteristics of fully developed turbulent flow due to different arrangement of VGs in a tube. The experiments were performed by using delta winglet vortex generators in a 52 mm circular copper tube. The flow regime varied from 6000 to 27000 Reynolds number. Four vortex generators with 45o angle of attack were used inside the circular tube. Different parameters of the VGs studied in this experiment such as lengths (L=10, 15, and 20 mm) and arrangements (R=0o to-15o). The results indicate that the length affected friction factor (f) and Nusselt number (Nu) significantly. L20 reached the highest f and Nu. The staggered arrangement concludes a significant drop on friction factor and a significant increase on Nusselt number. Consequently, the thermal performance of all staggered arrangement cases could reach a significant rise compared to the inline arrangement. The oil flow visualization could track down the trace of vortex behind the VG. The inline arrangement showed a strong vortex formed as a result of VG which was related to higher f while the staggered arrangement indicated a weak vortex.
AB - Vortex generator (VG) is one of the passive techniques which could improve the heat transfer with relatively low pressure drop. Vortex generators create streamwise longitudinal vortices which does not decay until far downstream that leads to have higher heat transfer with a lower pressure drop. The objectives of this experiment were to study the heat transfer and flow characteristics of fully developed turbulent flow due to different arrangement of VGs in a tube. The experiments were performed by using delta winglet vortex generators in a 52 mm circular copper tube. The flow regime varied from 6000 to 27000 Reynolds number. Four vortex generators with 45o angle of attack were used inside the circular tube. Different parameters of the VGs studied in this experiment such as lengths (L=10, 15, and 20 mm) and arrangements (R=0o to-15o). The results indicate that the length affected friction factor (f) and Nusselt number (Nu) significantly. L20 reached the highest f and Nu. The staggered arrangement concludes a significant drop on friction factor and a significant increase on Nusselt number. Consequently, the thermal performance of all staggered arrangement cases could reach a significant rise compared to the inline arrangement. The oil flow visualization could track down the trace of vortex behind the VG. The inline arrangement showed a strong vortex formed as a result of VG which was related to higher f while the staggered arrangement indicated a weak vortex.
KW - Delta winglet vortex generators
KW - Oil flow visualization
KW - Thermal performance enhancement
UR - http://www.scopus.com/inward/record.url?scp=85076417559&partnerID=8YFLogxK
U2 - 10.1115/AJKFluids2019-4723
DO - 10.1115/AJKFluids2019-4723
M3 - Conference contribution
AN - SCOPUS:85076417559
T3 - ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
BT - Fluid Mechanics
T2 - ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference, AJKFluids 2019
Y2 - 28 July 2019 through 1 August 2019
ER -