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NASA Glenn Research Center
Grid for a turbine stage CFD Codes for Turbomachinery, Dr. Rodrick V. Chima, NASA Glenn Research Center, Cleveland, Ohio, USA Pressure contours on a turbine stage
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GRAPE v. 107

Overview
The GRAPE code (GRids about Airfoils using Poisson's Equation) is an elliptic grid generator originally intended for isolated airfoils. The code was written by Reece Sorenson at NASA Ames Research Center, and was modified by Rod Chima at NASA Glenn to allow generation of periodic C-type grids for turbomachinery blades. Turbomachinery grids generated with GRAPE can be used directly with the RVCQ3D CFD code.

Applications

  • Axial compressors and turbines
  • Centrifugal impellers and radial diffusers (no splitters)
  • Pumps
  • Linear cascades
  • Isolated airfoils
  • Supports all options in Sorenson's original code

Grid Types
The geometry input to GRAPE is completely general. If you can generate coordinates for your geometry, GRAPE can probably put put a grid around it.

  • C-grids around blades
  • C- and O-grids around airfoils
Features
  • Arbitrary specification of inner and outer boundary points
  • Several options for reclustering boundary points
  • Interior points are generated as a solution of a Poisson equation.
  • Forcing terms in the Poisson equation maintain grid spacing and angles at the boundaries.
  • Version 107 uses new monotone splines for accurate geometry definition.
Input and output
  • Namelist input
  • Airfoils are input in a Cartesian (x,y) coordinate system.
  • Turbomachinery blades are input in a cylindrical (m,rbar*theta) system, where m is the arc length along the surface and rbar is a mean radius.
  • Grid files are written as binary data in standard PLOT3D format
  • Grid files can be read directly by RVCQ3D.
  • Minimal printed output

Computer and graphics requirements
GRAPE requires a Fortran 90 compiler and CFD visualization software for use. Click the button below for more information.



Test cases included with GRAPE 107

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Image of an C-grid for fan blades

C-grid, NASA rotor 37,
70 percent span

Image of a grid for a centrifugal impeller

C-grid, NASA 6:1
centrifugal impeller

Image of a grid for turbine vanes

C-grid, Goldman annular
turbine vane

Grid around a supercritical airfoil

O-grid, Garabedian and Korn airfoil

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Curator: John Slater
NASA Official: Mary Jo Long-Davis
Last Updated: 05/04/2012