Effect of operating and geometrical parameters of tangential entry type dual swirling flame burner on impingement heat transfer

Abstract

An experimental study has been carried out to investigate the impingement heat transfer characteristics of a tangential entry type dual swirling flame burner. The effects of variation of operating parameters viz.; Reynolds numbers (Re(i) = 700–1000, Re(o) = 5000–13,000), equivalence ratio (ϕ(o) = 0.8–1.2), dimensionless separation distance (H/Dh = 1–5), and ratio of tangential to axial in-flows (T:A = 40:60–100:0) have been analyzed. The effects of geometrical design parameters including position of tangential entry port, port diameter (Dp) and number of ports (Np) have also been investigated. The flame shapes are examined under different geometrical design parameters and operating conditions. Heat transfer characteristics revealed that moderate separation distances (H/Dh ~ 3) and moderate values of T:A (~60:40) are the most favorable operating variables for optimum utilization of heat to the impingement surface. Also, moderate values of Re(o) (~9000) at fuel rich conditions (ϕ(o) ~ 1.1) are more appropriate for maximum heat transfer to the surface. Although, Reynolds number (representing firing rate) is the most significant parameter but other parameters like, T:A, H/Dh and ϕ(o) also contribute notably to the transmission efficiency. Intensity of swirl changes significantly with variation of the geometrical design parameters, which showed a major influence on the impingement heat transfer. The present study concludes that tangential entry type dual swirling flame burner offers flexibility in optimizing the heat transfer to the impingement surface for a given set of burner geometrical design parameters and operating conditions.