A numerical investigation on flow through 2-D and 3-D coaxial nozzle burners

Flow through annulus occurs in numerous practical devices such as gas turbine intercooler, pulverized coal burner etc. A complete understanding of the flow-field inside the annulus is required to design and size the flow duct for these applications. This work presents a numerical study on laminar and turbulent flows through two-dimensional annulus of different outer and inner wall contours. The study is aimed at understanding the effects of nozzle contours on annulus exit velocity profile. Flows through annulus of fifth, fourth, and third degree polynomial outer wall and fifth order polynomial inner wall are computed by solving compressible Navier-Stokes equation over two dimensional computational domains. A Favre averaged form of the equation is used to compute mean and turbulent fluctuations. Furthermore, the length of the fifth degree wall is varied to understand the effects of wall dimension. Initial results show that exit velocity profile is independent of wall length however different combinations of outer and inner wall profiles yield nonuniform velocity profiles at the exit of the annulus.