Journal of Enhanced Heat Transfer

DOI: 10.1615/JEnhHeatTransf.v11.i4.140

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Performance Comparison Between Wire Coil and Twisted Tape Inserts

Karl Ponweiser
Vienna University of Technology, Institute of Applied Thermodynamics, Vienna, Austria

Wladimir Linzer
Institute of Thermal Engineering, Vienna University of Technology, Getreidemarkt 9, Vienna, A-1060, Austria

Marina Malinovec
Faculty of Mechanical Engineering and Naval Architecture, Zagreb, Croatia

ABSTRACT

This work presents experimental results for heat transfer caused by convection of air in tubes with wire coil and twisted tape inserts. The characteristic parameters of the inserted tubes under investigation are length and position in the tube of the tested inserts. All tests are performed in a turbulent flow regime. Significantly higher inside heat transfer and friction factor coefficients than those of the smooth tube under same operating conditions have been observed. The performance of the wire coil and twisted tape inserts has been evaluated by three different criteria: maximizing heat transfer rate, minimizing heat exchanger size, and minimizing pumping power.