Throughflow model for design and analysis integrated in a three-dimensional Navier-Stokes solver

A multiblock multigrid Navier-Stokes solver has been extended to include a throughflow model for the design and analysis of turbomachines. The presenc e of the blades in the inviscid axisymmetric flow is modelled in the classi cal way through a distributed blade force to produce the desired turning, a blockage factor that accounts for the reduced area due to blade thickness, and a distributed frictional force representing the entropy increase due t o viscous stresses and heat conduction. The exact blade geometry is not req uired. All features of the three-dimensional code concerning the physical f luid model, boundary conditions, spatial and time discretization, convergen ce acceleration techniques and data visualization are available to the thro ughflow module. This includes the capability to treat the entire range of r elevant Mach numbers, from strictly incompressible (through a preconditioni ng technique) to supersonic, as well as any number of blade rows in any con figuration, including, for example, bypass engines. Selected elements compr ising the throughflow model are discussed, with special emphasis on the bla de force and its discretization. The properties of analysis and design mode with respect to shocks and the associated losses are investigated. The met hodology is demonstrated on a transonic compressor rotor and a four-stage l ow-speed turbine.