Investigation of thermal performance and entropy generation in a helical heat exchanger with multiple rib profiles using AlO-water nanofluid

Numerical investigation on the impact of different design arrangements of helical heat exchangers with varying cross-sections utilizing ternary hybrid nanofluids

“…The factors encompass features related to thermal properties, hydraulic properties, and entropy formation. The formula to evaluate the Nusselt number ( Nu ), is presented below, which is the dimensionless quantity employed to characterize the features of heat transport [ 27 ]: In this equation, the surface heat transfer coefficient (W/m 2 K) is denoted by h, the thermal conductivity (W/m-K) using k and the hydraulic diameter (m) is denoted by D h .…”

“…Although helical tube heat exchangers have been extensively studied, with research focusing on the alteration of surfaces [ 25 , 26 ], variation of inlet profiles [ 27 ], optimization of curvature parameters [ 28 , 29 ] and the use of conventional fluids are found to be inefficient in terms of overall heat transmission, primarily for their lower thermal-conductivity. Therefore, the adoption of nanofluids has gained significant interest throughout the years.…”

“…Therefore, to achieve greater efficient design, comparison among different design configurations of HTHE is needed which are studied by several research attempts [ 19 , 20 , 47 , 48 ]. Moreover, varying the cross section can lead to improved flow dynamics and various pressure drops [ 4 , 13 , 27 ]. But, to the best of the author's knowledge, no study has been conducted on the comparison of innovative helix designs with the alteration of inlet profiles.…”

Experimental investigation of the thermal-hydraulic performance of conically coiled tubes using Al2O3/water nanofluid

“…𝑄 Ȧ (𝑇 𝑤,𝑥 − 𝑇 𝑏,𝑥 ) (13) where 𝑇 𝑤,𝑥 is the wall surface temperature and 𝑇 𝑏,𝑥 is the fluid bulk temperature at each location.…”

“…Results demonstrated that the h increased by 6.4%, 19.0%, and 23.7%, respectively, for heat fluxes of 2283 and 4975 W/m 2 at a 1 wt% concentration of Al2O3/water nanofluid compared to pure water. Hasan and Bhuiyan [13] investigated the thermal performance and the entropy generation of a HCT heat exchanger with different coil revolutions utilizing a 5% concentration of Al2O3/water nanofluid. Results demonstrated that when coil revolutions increase, the total HTR and friction factor increase.…”