Abstract:
An experimental investigation was carried out for turbulent flow heat transfer in a
circular tube with perforated rectangular strip inserts. Mild steel perforated
rectangular strips with holes of different diameters were used as inserts in this
experiment. Heat transfer and pressure drop characteristics were obtained in the tube
for the turbulent flow. The flow of air through the tube was varied by using the flow
control valve. Heat transfer and pressure drop data were taken for Reynolds numbers
ranging from 1.5 x 10 4 to 4.7 x 10 4. Air velocity, temperatures, tube wall
temperatures, pressure drops were measured for the plain tube as well as for the tube
with perforated rectangular strip inserts. Heat transfer coefficients, heat transfer rate,
Nusselt numbers, friction factor, blower power and heat transfer effectiveness were
calculated using measured variables for the plain tube as well as for the tube with
inserts. Heat transfer rate was found to be increased up to 1.85 times with
corresponding increase in friction factor and blower power for the tube with
perforated rectangular strip inserts. For the comparable Reynolds number, the heat
transfer coefficient for the tube with perforated rectangular strip inserts was found to
be increased up to 2.80 times than that of the plain tube. The friction fator for the
tube with perforated rectangular strip inserts was found to be increased up to 1.8
times compared to that of the plain tube.Whereas, the required blower power for the
tube with perforated rectangular strip inserts was found to be increased up to 1.45
times than that of the plain tube. It was also found that the heat transfer effectiveness
for the tube with perforated rectangular strip inserts was increased up to 2.45 times
compared to that of the plain tube. With the experimental data, a correlation was
developed for prediction of the heat transfer in the turbulent flow for the tube with
. perforated rectangular strip inserts.
