旋回流燃焼器近傍の空力特性 : 第3報,等温旋回流に与えるブラフボディと一次噴流の影響

Isothermal annular swirling flows were investigated to clarify the effects of a bluff body and a nonswirled central air jet upon the characteristics of swirl-induced recirculation zones. The velocity measurement using an LDA system revealed that the use of a bluff body increased the rate of recirculating mass flow and also the mass flow brought back into the quarl (or expansion) section. For flows with a primary air jet, two distinct flow patterns were observed: (I) ordinary IRZ (Internal Recirculation Zone) and (II) IRZ with primary air jet penetration. The IRZ strength could be determined by the combined parameter, Sa(D1/Do)2, where the swirl number is Sa and the vortex diameter expansion ratio is D1/Do.