Novel design of natural solar air heat for higher thermal performance utilizing porous vortex generator

Abstract

In this study, the thermal performance of a 2-D turbulent natural convection airflow inside a solar air heater is improved by using a flexible porous vortex generator, which is a self-sustained passive oscillator. The inclined thin elastic porous winglet, used as vortex generator, is attached on the heated wall for flow mixing and convection enhancement. Ongoing vortices, due to the resultant fluid–structure interaction, disrupts the thermal boundary layer, which then leads to the mixing process and improving the heater’s performance. Using a porous vortex generator, instead of its main competitor, the solid winglet, not only decreases the blockage effect and causes a higher airflow rate, but also results in a higher mean outlet-temperature by more mixing rate. To demonstrate the benefits of this idea, a numerical simulation considering a two-way strongly-coupled FSI approach in transient condition is done. The present numerical results are validated against the experimental and numerical data. It’s found that employing porous vortex generator confers considerable performance enhancement up to 500% on air temperature increase respect to the conventional clear solar air heater (from 8 to 40.5 °C) while providing a higher airflow rate 8.3% and outlet-temperature (135%) in comparison with solid winglet. This study aims to make the renewable thermal-solar system more efficient and affordable so that the industrial society will become more interested toward sustainable infrastructure.