Experimental study of thermal characteristics of alternatively twisted swirl generator tape in a heat exchanger tube

ABSTRACT

The heat transfer capacity of a convectional heat exchanger needs to be increased to minimize size and cost. Inserts are a promising way to enhance heat transfer at a bearable penalty in pressure drop. The objective of this study is to evaluate experimentally the thermal-hydraulic characteristics of a heat exchanger tube inserted with a novel alternatively twisted swirl generator (ATSG) tape. The experimental data has been collected for nine distinct combinations of ATSG tapes, includes the tapes with three twist angles (45°, 60°, and 90°) and three twist ratios (3, 4 and 5) for Reynolds numbers of 4,000 to 20,000. The use of ATSG tapes resulted in a considerable improvement in heat transfer rate compared to simple twisted tapes (TT). Over the range evaluated, heat transfer coefficient, pressure drop and thermal performance factor (TPF) with ATSG tapes in a tube are, respectively, 1.57–1.82, 1.58–2.54, and 1.22–1.46 times to that of simple TT in a tube. The maximum TPF achieved is 1.52 for ATSG tape with twist ratio of 3 and twist angle of 90°. The TPF for any combination of ATSG tapes is greater than one, which signifies that it is an efficient approach.

KEYWORDS:

• Twisted tape
• Reynolds number
• heat transfer enhancement
• Nusselt number
• effectiveness

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Additional information

Notes on contributors

Bhavik V. Patel

Bhavik V. Patel is a Ph.D. scholar in Department of Mechanical Engineering at Maulana Azad National Institute of Technology, Bhopal, India. He has received an M. Tech degree in Thermal Engineering from the Maulana Azad National Institute of Technology, Bhopal, India. His research fields include computational fluid dynamics, heat transfer and nanofluid.

R.M. Sarviya

R. M. Sarviya is a Professor in Department of Mechanical Engineering at Maulana Azad National Institute of Technology, Bhopal, India. He has received his Ph.D. from the Indian Institute of Technology, Roorkee, India. His research fields include heat transfer, thermal engineering, and solar energy. He has undergone research-training experience at Rediff University (UK), University of Wales (Cardiff, UK), and University of Salford (Manchester, UK). He has published more than 125 papers. He has guided 14 Ph.D. and presented papers in many countries at conferences.

S.P.S. Rajput

S.P.S. Rajput is a Professor in Department of Mechanical Engineering at Maulana Azad National Institute of Technology, Bhopal, India. His research fields include thermal engineering, refrigeration and air conditioning, energy conversion cycles, and human thermal comfort. He has published more than 120 papers. He has guided 18 Ph.D. and visited countries including the USA, China, and Thailand.