TY - JOUR
TI - Experimental studies on effect of wire coiled coil matrix turbulators with and without bonding on the wall of the test section of concentric tube heat exchanger
AU - Selvam Swaminathan
AU - Thiyagarajan P R
AU - Suresh Sivan
JN - Thermal Science
PY - 2012
VL - 16
IS - 4
SP - 1151
EP - 1164
PT - Article
AB - This paper presents the effect of bonding and without bonding of wire coiled  coil matrix turbulator on the heat transfer for a fully developed turbulent  flow. Experiments are conducted by maintaining constant wall temperature.  Tests are performed on 3 different wire coiled coil matrix turbulators of  different pitches of 5, 10 and 15 mm without bonding of the turbulator. Three  similar types of heat exchangers are fabricated and the wire coiled coil  matrix turbulators with different pitches of 5, 10 and 15mm are inserted in  the heat exchangers and bonding is done on the surface of the tube section.  Results have indicated that the heat transfer rate enhances inversely with  the pitch of the wire coiled coil matrix turbulator with bonding. With a  pitch of 5 mm, the turbulators without bonding have resulted in almost 25.4%  enhancement when compared with plain tube. On the other hand, for pitches of  10 mm and 15 mm the enhancement were 20.7% and 16.8%, respectively. The  empirical correlations developed for turbulators with and without bonding  results in ±6% deviation for Nusselt number and ±3% for friction factor.  Similarly with a pitch of 5 mm, the turbulators with bonding have resulted in  almost 42% enhancement. For pitches of 10mm and 15mm the enhancements were  34.7% and 25%, respectively.