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

Thermal Science

关键词: turbulent flow;    wire coiled coil matrix turbulator;    pitch;    heat transfer;    bonding;   

DOI  :  10.2298/TSCI110318117S

来源: DOAJ

【 摘 要 】

This paper presents the effect of bonding and without bonding of wire coiledcoil matrix turbulator on the heat transfer for a fully developed turbulentflow. Experiments are conducted by maintaining constant wall temperature.Tests are performed on 3 different wire coiled coil matrix turbulators ofdifferent pitches of 5, 10 and 15 mm without bonding of the turbulator. Threesimilar types of heat exchangers are fabricated and the wire coiled coilmatrix turbulators with different pitches of 5, 10 and 15mm are inserted inthe heat exchangers and bonding is done on the surface of the tube section.Results have indicated that the heat transfer rate enhances inversely withthe pitch of the wire coiled coil matrix turbulator with bonding. With apitch 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 of10 mm and 15 mm the enhancement were 20.7% and 16.8%, respectively. Theempirical correlations developed for turbulators with and without bondingresults in ±6% deviation for Nusselt number and ±3% for friction factor.Similarly with a pitch of 5 mm, the turbulators with bonding have resulted inalmost 42% enhancement. For pitches of 10mm and 15mm the enhancements were34.7% and 25%, respectively.

【 授权许可】

Unknown