Abstract:
This paper represents tube side pressure drop, friction factor, heat transfer coefficient, heat transfer rate,
enhancement of heat transfer efficiency and percentage of increase in those parameters for water using V-shaped twisted tape inserts of copper and stainless steel material into a plain tube. The test section is a circular tube made of copper having 26.6 mm inside diameter, 30 mm outside diameter and 939.8 mm in length, of which 900 mm is of effective length.
V-cut twisted tape inserts are made of as 800 mm length, 1.5 mm thickness, twisted ratio 5 and width and depth of 8
mm are used in this experiment. The test section is perfectly insulated and electrically heated. Five k-type
thermocouples are used for measuring wall temperature. Experimental Nusselt number is found ranging from 34.65 to
69.25 for smooth copper tube without insert whereas, 110.9 to 250.9 for V-cut twisted tape insert of stainless steel and
121.1 to 331.8 for V-cut twisted tape insert of copper. Heat flux is obtained ranging from 9163.8W/m2 to 15828.3W/m2
without insert, 18327.5 W/m2 to 31656.6W/m2 for stainless steel insert and 18327.5W/m2 to 39570.8W/m2 for copper
insert. An increment of heat transfer of copper insert is as 2.52 times and of stainless steel insert as 2.5 times more than plain tube without an insert. Convective heat transfer coefficient is found as 3.2, 3.5 times more than the plain smooth tube for stainless steel insert and copper insert. Heat transfer enhancement efficiency using stainless steel insert and the copper insert is increased 3.2, 4.3 times more than plain tube without insert.
