Abstract (EN):
Three major difficulties may occur in the calculation of gas-turbine combustor flows: the exact representation of the combustor geometrical features, the specification of the inlet boundary conditions and the need for very fine grid calculations. Simplifications are needed to circumvent the above difficulties, within the capacities of numerical techniques and computer systems currently available. The present study, by comparison between numerical and experimental results obtained inside a water model of a gas turbine combustor, assesses the effectiveness of some of the solutions sought, which may affect the accuracy of the results and preclude the appraisal and consequent development of physical models embedded in available computational fluid dynamics codes. It is shown that of all the boundary conditions, the radial velocity on the primary hole is the most important. Numerical accuracy can be substantially improved by careful distribution of the grid nodes, particularly around the primary jet axis, and grids with a total of 40 000 grid nodes were found to offer a good compromise between computation time and numerical accuracy. These grids also enabled a reasonably good geometrical representation of the combustor, removing the need for more sophisticated grid system compared to the standard cylindrical polar one, used in the present study. © 1992.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica