4.4. Meshing strategy

Adapted meshing strategy for both the impeller and diffuser fluid domains was achieved using Ansys-Turbo grid module. A total node count of 7e-01 million was setup for the CFD solver, as it allows generation of refined quality hexahedral meshes required for the blade passages in turbo-machinery.

within the recommended range of 0.4 to 0.6. A maximum flow angle of 64� at the impeller exit

Numerical Simulations of a High-Resolution RANS-FVDM Scheme for the Design of a Gas Turbine Centrifugal…

� with zero

http://dx.doi.org/10.5772/intechopen.72098

� with 107

Figure 2. (a) Inlet Mach triangles for impeller blades only in radial section with backward swept blades, β<sup>2</sup> ¼ 0

swirl at entry; (b) exit Mach triangles for impeller blades only in radial section with backward swept blades, β<sup>2</sup> ¼ 0

Blade to blade contours for absolute Mach number at hub, mean and tip sections are presented

The absolute Mach number plots show no supersonic regions of significant volume. The hub section plot show supersonic flow near suction surface of the blade and the tip Section span plots show a supersonic region on the pressure surface of the blade. The presence of a mild bow shock in front of the leading edge of the blade can also be observed. The Mach number is around 0.6 at the leading edge of the impeller. The following plots shown in Figure 4(a–c) are

The Mach number at the leading edge in the relative frame is near 1.2 for the leading edge of the impeller blade. The regions of low Mach number can also be observed, although it is in the

Circumferential relative Mach number contours at the impeller inlet and outlet are presented in Figure 5(a) and (b). The higher color temperature indicates higher values of relative Mach

From above Figure 5(a), corresponding inlet relative Mach number contours shows that passage area is lying in the supersonic regime. The Figure 5(b) shows the effect of lean angle

and a Mach number of 1.4 are observed.

the relative Mach number contours for the hub, mean and tip.

5.2. Blade to blade contours

zero swirl at entry.

in below Figure 3 (a) and (c).

5.3. Circumferential contour

relative frame.

number.

of impeller blades.
