Accuracy of Numerical Results

Currently there are no experimental data available for the validation of nu­merical simulation of transport phenomena in a turbine-combustor. To validate the accuracy of the numerical results corresponding to the governing equations used, it was necessary to show that the results were independent of the grid which discretizes the computational domain. The verification of grid indepen­dence results was presented in [Isvoranu and Cizmas, 2002], where a one-stage turbine-combustor was simulated. Note that the grids were generated such that, for the given fbw conditions, the y + number was less than 1. Approximately 20 grid points were used to discretize the boundary layer regions.

Following the conclusions of accuracy investigation presented in [Isvoranu and Cizmas, 2002], the medium grid was used herein, since it provides the best compromise between accuracy and computational cost. This grid has 53 grid points normal to the airfoil and 225 grid points along the airfoil in the O-grid, and 75 grid points in the axial direction and 75 grid points in the circumferen­tial direction in the H-grid. The stator airfoils and rotor airfoils have the same number of grid points. The inlet and outlet H-grids have each 36 grid points in the axial direction and 75 grid points in the circumferential direction. The grid is shown in Fig. 1, where for clarity every other grid point in each direction is shown.