Numerical study of using perforated conical turbulators and added nanoparticles to enhance heat transfer performance in heat exchangers

Abstract

The current study investigates a two-phase turbulent nano uid ow inside a heat exchanger tube equipped with a novel type of conical turbulators having two parallel rows of holes for the rst time. The e ects of the number of the conical insert turbulators, number of the holes and volume fraction of the nanoparticles on ow eld, average Nusselt number, friction factor, and performance evaluation criterion have been numerically investigated. The results show that the proposed turbulators create vortices and recirculating currents that have signi cant e ect on heat transfer. As the number of the turbulators increases, Nusselt number increases obviously. However, the presence of holes reduces the friction factor and pressure drop that is related to lower resistance in the ow path. In general, the use of perforated conical turbulators improves Performance Evaluation Criterion (PEC) by creating controlled turbulent ows. On the other hand, the use of added nanoparticles also enhances heat transfer. The presented turbulators increase PEC by 43% compared to the smooth tube, if the parameters are determined properly. The maximum PEC of 1.43 is obtained at M = 8, N = 4, and Re = 4100, showing good performance compared to other types of turbulators.

Numerical Investigation of the Heat Transfer and Peristaltic Flow Through a Asymmetric Channel Having Variable Viscosity and Electric Conductivity

“…The properties of nanofluids, such as high thermal conductivity and enhanced viscosity, can affect the behaviour of peristaltic flow [30]. Additionally, the peristaltic motion can induce particle migration and concentration gradients in the fluid, leading to potential applications in drug delivery, microfluidics, and heat transfer [31]. However, the properties of 4 nanofluids can vary significantly with temperature, which can affect the behaviour of peristaltic flow and heat transfer.…”