ABSTRACT
An experimental analysis has been carried out for heat transfer and turbulent flow in a heat exchanger circular tube with solid ring with combined square wing twisted tape (TT) inserts. Experimentations are performed varying the solid ring with combined square wing TT insert parameters, such as changing the number of TT inserts from 1.0 to 4.0, ring pitch ratio
from 0.5 to 2.0, wing pitch ratio
from 2.0 to 3.5, wing depth ratio
from 0.083 to 0.333, ring diameter ratio
from 0.831 to 0.932, and Reynolds number
in the range of 3,000–21,000. The experimental results show that the heat transfer is increased around 5.66 times more than the plane circular tube. The thermal hydrodynamic performance is evaluated for the optimum range of solid ring with combined square wing TT insert parameters. Statistical correlations are developed and a deviation of correlation data from the experimental data of Nusselt number and friction factor is about ± 9% and ± 6%, respectively. The correlation is helpful in prediction of the thermal performance for turbulent flow through a circular tube with solid ring with combined square wing twisted tape inserts.
Nomenclature
= | Area of orifice plate, | |
= | Specific heat capacity of air, | |
= | Diameter of round pipe, | |
= | Distance between rings, | |
= | Internal diameter of rings, | |
= | Outside diameter of rings, | |
= | Ring ratio | |
= | Ring pitch ratio | |
= | Depth ratio | |
= | Flow friction | |
= | Head difference, | |
= | Heat exchanger tube | |
= | Fluid thermal conductivity, | |
L | = | Round pipe length, |
M | = | Mass stream rate of air, |
= | Number of twisted tapes | |
= | Nusselt number of solid ring with square wing inserts | |
ΔP | = | Pressure drop, |
= | Pitch between wings, | |
= | Wing pitch ratio | |
= | Heat flux, | |
= | Heat gain, | |
= | Reynolds number | |
= | Rayleigh number | |
= | Fluid inlet temperature, | |
= | Mean temperature, | |
= | Fluid outlet temperature, | |
= | Twisted tape | |
TTT | = | Typical twisted tape |
= | Total wall temperature, | |
= | Twist ratio | |
= | Airflow velocity, | |
= | Wings’ depth, | |
= | Width of tape, | |
= | Wing depth ratio |