Abstract:
Gas turbine combustor design represents an ambitious task in numerical and
experimental analysis. A significant number of competing criteria must be optimised
within specified constraints in order to satisfy legislative and performance requirements.
Currently, preliminary combustor flow and heat transfer design procedures, which by
necessity involve semi-empirical models, are often restricted in their range of
application.
The objective of this work is the development of a versatile design tool able to model all
conceivable gas turbine combustor types. A network approach provides the foundation
for a complete flow and heat transfer analysis to meet this goal.
The network method divides the combustor into a number of independent
interconnected sub-flows. A pressure-correction methodology solves the continuity
equation and a pressure-drop/flow-rate relationship. A constrained equilibrium
calculation, incorporating mixing and recirculation models, simulates the combustion
process. The new procedures are validated against numerical and experimental data
within three annular combustors and one reverse flow combustor. A full conjugate heat
transfer model is developed to allow the calculation of liner wall temperature
characteristics. The effects of conduction, convection and radiation are included in the
model. Film cooling and liner heat pick-up effects are included in the convection
calculation. Radiation represents the most difficult mode of heat transfer to simulate in
the combustion environment. A discrete transfer radiation model is developed and
validated for use within the network solver. The effects of soot concentration on
radiation is evaluated with the introduction of radial properties profiles. The accuracy of
the heat transfer models are evaluated with comparisons to experimental thermal paint
temperature data on a reverse flow and annular combustors.
The resulting network analysis code represents a powerful design tool for the
combustion engineer incoporating a novel and unique strategy.
