• CHEEPURUPALLI JYOTHSNA
• V. MANI KUMAR

Heat exchangers are the devices that have a vital necessity in various sectors such as chemical industries, food processing units and process industries for heating and cooling purposes. Improving its performance through various attempts is of great concern for many researchers. Enhancement of heat transfer by use nanofluids and turbulators is one of such attempts now a days. A triangular coil with core-rod (TCCR) inserted in Al2O3/Water nanofluid flow in a double pipe U-Return heat exchanger is the matter of investigation in this study for heat transfer analysis and enhancement. Four concentrations of 0.00%, 0.02%, 0.04% and 0.06% Al2O3 nanofluid is made to flow in heat exchanger with three separate designs of p/d-1, p/d-1.34, and p/d-1.79 TCCR. 3D Ansys Fluent software was utilized for simulation of heat exchanger. Al2O3 nanofluid flows in the inner tube and water in the outer tube of heat exchanger. Various nanofluid properties like density, thermal conductivity and viscosity, also performance parameters like temperature profile, rate of heat flow, NTU and effectiveness are analysed. Obtained results are indicating that both the design of TCCR and concentration of nanofluid had a significant effect on heat transfer. The outlet temperature of Al2O3 nanofluid increase with increase in p/d ratio and it decrease with increase in particle concentration. The lowest temperature of nanofluid was observed at particle concentration of 0.06% for p/d ratio of 1. An improvement of heat transfer by 1.5%, 3.85% and 4.55% in first design, 4.28%, 8.40% and 11.78% in second design and 4.60%, 8.17% and 6.20% in third design was achieved for 0.02%, 0.04% and 0.06% particle concentrations respectively, when compared 0.00% of particle concentration. The reasons for the heat transfer improvement at p/d-1 of 0.06% particle concentration is because of a greater number of turns in TCCR insert at p/d-1 which causes the fluid to swirl more and improved thermal conductivity of nanofluid at 0.06% when compared to other considered concentrations.

Triangular coil with core-rod (TCCR), Al2O3/Water nanofluid, Double pipe U-Return heat exchanger.

"HEAT TRANSFER ANALYSIS OF TRIANGULAR COIL WITH CORE ROD INSERTED IN Al 2 O 3 /WATER NANOFLUID FLOW IN A DOUBLE PIPE U-BEND HEAT EXCHANGER", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.7, Issue 10, page no.2505-2510, October-2020, Available :http://www.jetir.org/papers/JETIR2010325.pdf

"HEAT TRANSFER ANALYSIS OF TRIANGULAR COIL WITH CORE ROD INSERTED IN Al 2 O 3 /WATER NANOFLUID FLOW IN A DOUBLE PIPE U-BEND HEAT EXCHANGER", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.7, Issue 10, page no. pp2505-2510, October-2020, Available at : http://www.jetir.org/papers/JETIR2010325.pdf