Effect of typical and perforated discontinuous helical turbulators on flow and heat transfer in an air to
water double pipe heat exchanger is experimentally studied. Experimental analysis is conducted for different
values of open area ratio (0–0.0625), Reynolds number (6000–12,000) and pitch ratio (1.83–5.83).
According to experimental data, correlations for Nusselt number, friction factor and thermal performance
are presented as functions of variable parameters. Non-dominated Sorting Genetic Algorithm II (NSGA II)
is applied to find the optimal designs of high efficiency heat exchanger. Pareto front is presented as set of
multiple optimum solutions. Results show that friction factor and Nusselt number reduce with rise of
open area ratio and pitch ratio. Thermal performance is an increasing function of open area ratio while
it is a decreasing function of pitch ratio.
کلید واژگان :
Discontinuous helical turbulators Air to water heat exchanger Double pipe Friction Heat transfer NSGA II
