3D Navier-Stokes computing codes are tools that are commonly used today to design turbomachinery blades. When validating computing codes (elsA, Cedre), experimental database must be available for making comparisons. In order to test and validate advanced functionalities (models of turbulence, boundary conditions), the Turbomachinery team analyzes the calculations on different test cases.
The Rotor-37 Compressor
The rotor-37 is a transonic axial compressor, made up of a single rotor with 36 blades and rotating at 17,188 rpm. This test case is interesting because it can be used to test the robustness of the elsA code in the case of a shock/boundary layer interaction (fig. 1) or to validate the Chimera technique (superimposition of blocks that do not coincide). The Chimera method is used to study the technological effects (fig. 2), both in the inter-platform clearance zone (blade root) and at the tips of the rotor blades (casing treatment).
Figure 1: contours of the isentropic Mach number
at the test-section mid-height (above: experiment, bottom: computation)
Figure 2 : Chimère mesh (left) and streamlines (right) at the head
of the rotor-37 blades with 5 axisymetric grooves
The Vega2 Turbine
3D Navier-Stokes unsteady computation (elsA computation)
The Vega2 turbine is a transonic axial machine, made up of a 23 blade turbine nozzle and a 37 blade rotor. Its rotation speed is 13,000 rpm-1. The Vega2 machine is mounted on a test bench and is used to study stator/rotor type interactions in turbines. The Tumult project consists of a set of unsteady simulations of the flow in this machine (fig. 3). This project was used, in particular, to validate the chorochronic approach as opposed to a computation on the whole geometry of the turbine (mesh of 16.6 million points).
