Pressure Driven Temperature Field in a Combustion Chamber

Abstract

In this work numerical computation has been applied to investigate the temperature field in a gas turbine combustion chamber. The simulation considered pressure imbalance conditions of air flow between primary and secondary inlets. The combustion chamber under study is part of a 70 MW gas turbine from an operating combined cycle power plant. The combustion was simulated with proper fuel-air flow rate assuming stoichiometric conditions. Characteristic temperature and pressure fields were obtained under constant boundary conditions of air inlet. However, with pressure distribution imbalances of the order of 3 kPa between primary and secondary air inlets, excessive heating in regions other than the combustion chamber core were obtained. Over heating in these regions helped to explain what was observed to produce permanent damage to auxiliary equipment surrounding the combustion chamber core, like the cross flame pipes. It is observed that high temperatures which normally develop in the central region of the combustion chamber may reach other surrounding upstream regions by modifying slightly the air pressure. Scanning microscope examination of the damaged material confirmed that it was exposed to high temperatures such as predicted through the numerical computation.