Investigating the influence of flexible flags on heat transfer through experimental analysis

ABSTRACT

The impact of flexible flags vortex generators (FFVGs) positioned on the channel surface on friction factors and the transfer of heat were examined experimentally in this work. Within the scope of the study, the width (w), length (L), height from the ground (c), and position on the channel surface of the determined flexible flags were emphasized. FFVGs are placed in four different positions on the channel surface. The experiments were achieved with four various the number of Reynolds (from 10000 to 30000) using air as the fluid. The temperature changes on channel surface were observed by the thermal imaging method. The Nusselt numbers, friction factor, heat transfer coefficient and heat performance factor were investigated in the study. In the study carried out, Taguchi methodology was employed to establish the optimal values of the parameters used and the L₁₆ (4⁵) orthogonal array was selected. The Taguchi method took into account the number of Nusselt, the factor of friction, and the factor of thermal enhancement as performance factors. The results of flexible flags’ heat transfer in various positions are compared to those of a smooth plate. As a result, the thermal performance factor was increased to 1.38 and the Nusselt number to 2.02, respectively, in comparison to the smooth canal, by using flexible flags.

KEYWORDS:

• Heat transfer augmentation
• flexible flags
• vortex generator
• thermal imaging technique
• Taguchi method

Disclosure statement

No potential conflict of interest was reported by the author(s).