Commercial pressures to reduce time-scales encourage innovation in the design and
analysis cycle of gas turbine combustion systems. The migration of Computational
Fluid Dynamics (CFD) from the purview of the specialist into a routine analysis tool is
crucial to achieve these reductions and forms the focus of this research. Two significant
challenges were identified: reducing the time-scale for creating and solving a CFD prediction
and reducing the level of expertise required to perform a prediction.
The commercial pressure for the rapid production of CFD predictions, coupled with the
desire to reduce the risk associated with adopting a new technology led, following a
review of available techniques, to the identification of structured grids as the current
It was decided that the task of geometry definition would be entirely performed within
commercial Computer Aided Design (CAD) systems. A critical success factor for this
research was the adoption of solid models for the geometry representation. Solids
ensure consistency, and accuracy, whilst eliminating the need for the designer to undertake
difficult, and time consuming, geometry repair operations. The versatility of parametric
CAD systems were investigated on the complex geometry of a combustion system and found to be useful in reducing the overhead in altering the geometry for a
CFD prediction. Accurate and robust transfer between CAD and CFD systems was
achieved by the use of direct translators.
Restricting the geometry definition to solid models allowed a novel two stage grid generator
to be developed. In stage one an initial algebraic grid is created. This reduces
user interaction to a minimum, by the employment of a series of logical rules based on
the solid model to fill in any missing grid boundary condition data. In stage two the
quality of the grid is improved by redistributing nodes using elliptical partial differential
equations. A unique approach of improving grid quality by simultaneously smoothing
both internal and surface grids was implemented. The smoothing operation was
responsible for quality, and therefore reduced the level of grid generation expertise
The successful validation of this research was demonstrated using several test cases
including a CFD prediction of a complete combustion system.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.