Heat transfer distribution for three interacting methane–air premixed impinging flame jets

Abstract

Multiple impinging flame jets are widely used in industrial heating (Ex. ladle preheating) and melting applications (Ex. glass forming). In the present method, high resolution heat flux distribution is obtained by applying the inverse heat conduction technique using thermal infrared camera. The high resolution thermal imaging enables to capture the steep gradients of spatial heat flux distribution. Nusselt number and effectiveness distributions are obtained by analytical–numerical method of estimation of the adiabatic wall temperature. Three circular tube burners arranged in a staggered pattern with inter tube spacing (S/d) of 2 to 6 is considered. The ratio of distance from tube burner tip to the impingement plate (z/d) is varied from 2 to 6 while the Reynolds number is varied from 400 to 1000. For the smallest S/d=2, the interaction amongst the flames is significant and leads to non-circular hot spot distribution for heat flux. The average Nusselt number and average effectiveness are higher for higher Re for all z/d unless the inner premixed cone touches the impingement plate. The average Nusselt number and average effectiveness are marginally higher for smaller S/d for the same z/d and Re. The coefficient of variance increases with the increase in S/d.