Abstract
[Display omitted]
•Energy and exergy performance of the tube heat exchangers with finned coiled wire insert were discussed.•Equations were proposed for calculation of objective variables.•Multi-objective study was implemented to obtain the optimum conditions.
In the current investigation, CFD (computational fluid dynamics) code is applied for the three-dimensional simulation of fluid flow and turbulent transferred thermal energy through circular duct with coiled finned wire inserts. The realizable K-ε model will be used for the obtaining the influence of the turbulence. The validation of the model is performed by comparing the numerical Nusselt number with the experimental one. The impact of the various operating parameters i.e. Prandtl and Reynolds numbers and geometric variables i.e. fin height and thickness, coil pitch and wire diameter on the dimensionless exergy loss, thermal efficiency and the dimensionless working power will be obtained. Furthermore, correlations will be suggested to estimate these objective variables as functions of the geometric and operating variables. A new multi-objective optimization way is introduced and applied to obtain the optimal and critical values or range of the input variables in the studied range. Results also show if the Reynolds number increases by 100 % in the study range, the thermal efficiency, the dimensionless exergy loss and dimensional working power reduces by 15.9 %, 9.4 % and 5.9 %, respectively. Furthermore, with doubling pitch, they reduce 17.2 %, 14.9 % and 48.9 %, respectively.