Investigation of the three-dimensional turbulent flow fields of the gas swirl burner with a cone type baffle plate (I)

Abstract

This paper presents three-dimensional mean velocities, turbulent intensities and Reynolds shear stresses measured in the Y-Z plane of the gas swirl burner with a cone type baffle plate by using an X-type hot-wire probe. This experiment is carried out at the flow rate of 450 l/ which is equivalent to the combustion air flow rate necessary to heat release 15,000 kcal/hr in a gas furnace. Mean velocities and turbulent intensities etc. show that their maximum values exist around the narrow slits situated radially on the edge of and in front of a burner. According to downstream regions, they have a peculiar shape like a starfish because the flows going out of the narrow slits and the swirl vanes of an inclined baffle plate diffuse and develop into inward and outward of a burner. The rotational flow due to the inclined flow velocity going out of swirl vanes of a cone type baffle plate seems to decrease the magnitudes of mean velocities V and W respectively by about 30 % smaller than those of mean velocity U. The turbulent intensities have large values of 50 %–210 % within the range of 0.5<r/R<1 and around the narrow slits in front of a burner because the large transverse slope of axial mean velocity remains in these region. Therefore, the combustion reaction is expected to occur actively near these regions. Moreover, the Reynolds shear stresses are largely distributed near the narrow slits of a burner.