PERFORMANCE ENHANCEMENT OF TUBULAR AIR PRE-HEATER WITH DIFFERENT TUBE DIAMETERS AND PROFILES
The presented article discuses the performance of tubular air pre-heater based on the different tube diameter and tube profile. Two different tube diameters i.e. OD 60.3 mm and OD 48.3 mm (BS 6323 / IS 3601) have been considered in the present study. Moreover, the effects of both plain and multi rifled (internally ribbed) tube profiles on the performance of air pre-heater are presented. There is substantial savings in material with tubes of OD 48.3 mm compared to tube with OD 60.3 mm. Multi Rifled Tubes (Ribbed Tubes) improve heat transfer and thermal performance of air pre-heater in comparison to plain walled tubes. There is increase in air output temperature by about 1%, drop in flue gas temperature by 0.5%, increase in pressure drop by around 23% and increase in tube side flue gas velocity about 10% with use of tube OD 48.3 mm compared to tube OD 60.3 mm. Similar results are observed between internally ribbed tubes and plain tubes.