Augmentation of heat transfer performance in coiled flow inverter vis-à-vis conventional heat exchanger

In the present work, primarily two studies were carried out to ascertain the performance of coiled flow inverter (CFI) as heat exchanger at pilot plant scale. In the first study, performance of CFI heat exchanger has been compared with conventional heat exchangers, i.e. shell and tube heat exchanger (SHE) and plate type heat exchanger (PHE) under identical heat transfer area and process conditions. Experiments were conducted with water flowing under laminar flow regime within the flow range of 30–300 kg/h in the tube side of SHE and PHE. Friction factor and Nusselt number calculated from present experimental study in SHE and PHE were compared with the experimental data previously reported for CFI heat exchanger (Kumar et al., 2007). The Number of Transfer units (NTU) calculated in the present study for CFI was nearly 3.7–7.5 times higher as compared to SHE and 2–2.5 times higher as compared to PHE. In the second part of the study, experiments were performed first time to investigate the pressure drop and heat transfer of compressed air flowing under turbulent flow condition in CFI heat exchanger at pilot plant scale. Hot air at elevated pressures (10–30 kg/cm2) in the tube side of CFI heat exchanger with flow range 3×104