Enhancement of cooling characteristics and optimization of a triple concentric-tube heat exchanger with inserted ribs

Experimental and numerical investigation of the triple concentric-tube heat exchanger with inserted ribs has been carried out. The purpose is to evaluate the performance characteristics of the triple tube heat exchanger with rib inserts. The investigation key design parameters involve water mass flow rate, flow pattern, temperature variation, rib height and rib pitch. Numerical CFD modeling is developed using FLUENT commercial code and validation criteria is done to extend the study parameters with extra ranges. The results revealed that, the insertion of ribs to the inner annulus fluid flow of the triple tube heat exchanger participate a significant enhancement of the convective heat transfer. Higher performance index is obtained at higher rib pitch and lower rib height. A set of empirical expressions with the dimensionless design parameters have been predicted based on the obtained data.