Taguchi-based optimization of a fluidic oscillator for enhanced thermal-hydraulic performance of an impinging sweeping jet

This study focuses on enhancing the thermal and hydraulic characteristics of a double feedback fluidic oscillator by optimizing the Coanda surface geometry. The primary objectives include augmenting oscillation frequency and jet deflection angle, followed by evaluating and enhancing the thermal performance of the optimized configurations against a baseline smooth oscillator. The Taguchi optimization approach was utilized, incorporating three design parameters for flow analysis at various levels of aspect ratio, number of ribs, and rib angle. Four factors, oscillator design group, Reynolds number, jet-to-target distance, and target surface length, were considered at different levels for thermal performance evaluation. A two-dimensional computational fluid dynamics model was implemented, and an L9(33) orthogonal array was employed to assess the effects of design variables on individual responses. The oscillators with the highest flow performance showed an improvement in oscillation frequency by almost 20 % and a notable increase in jet deflection angle by close to 40 % relative to the baseline design. Heat transfer analysis revealed a 24.3 % improvement in Nusselt number (Nu) compared to the smooth oscillator, with a performance evaluation criterion (PEC) of 1.252 achieved using the optimized frequency design.