Heat transfer computations of internal duct flows with combined hydraulic and thermal developing length

Abstract

kThis study investigated the Navier-Stokes L computations of the surface heat transfer coefficients of a transition duct flow. A transition duct from an axisymmetric n cross section to a nonaxisymmetric cross section, is usually used to connect the turbine exit to the nozzle. As the gas Pr turbine inlet temperature increases, the transition duct is subjected to the high temperature at the gas turbine exit. pThe transition duct flow has combined development of hydraulic and thermal entry length. The design of the Qw transition duct required accurate surface heat transfer coefficients.The Navier-Stokes computational method R could be used to predict the surface heat transfer coefficients

Numerical Simulation of Developing Compressible Turbulent Flow with Heat Transfer

“…However, there is a good agreement between the centerline velocity of the present work and the experimental data [19] in the range of 0 < Z=D < 50. This agreement no longer holds after Z=D 10 between the present work and the numerical results of Wang et al [18] using a Baldwin-Lomax eddy viscosity model. Figures 6 and 7 illustrate the distribution of friction factor and Nusselt number along the pipe.…”

“…Also, the pipe wall roughness and the air Prandtl number were set to " 4:6 10 5 m and Pr 0:71. Figures 4 and 5 show the centerline velocity and pressure along the pipe, respectively, compared with the numerical results of Wang et al [18] and experimental data of Ward-Smith [19]. The flow velocity profile does not reach a fully developed condition at Z=D 50, because in compressible flow, the velocity profile increases continuously along the pipe.…”

“…In these figures, the mesh size is uniform in the z direction, but clustered toward the wall, with the smallest mesh size of y 1 and a stretching ratio of 1:01. The numerical results of Wang et al [18] computed with uniform grid node spacing show that the friction factor increases a little after Z=D > 30, but the Nusselt number always decreases. The same behavior is seen in the present work if more grid nodes are used in the z direction (more than 301 points).…”