In which section of the gas turbine does the highest gas volume typically occur?

The section of the gas turbine where the highest gas volume typically occurs is at the turbine outlet. As air passes through the compressor, it is compressed and then enters the combustor, where fuel is added and ignited. This process significantly increases the temperature and pressure of the gas.

Upon exiting the combustor, the high-pressure, high-temperature gas expands through the turbine, where it drives the turbine blades. This expansion results in a reduction in pressure but an increase in volume as the hot gases move towards the turbine outlet. By the time the gases reach the turbine outlet, they have effectively expanded, allowing for a greater volume of gas to be present as compared to the inlet or other sections of the gas turbine.

The exhaust duct follows this, but its primary role is to direct the gases away from the turbine, rather than being a point of maximum volume. The combustor is where the combustion process occurs, which certainly involves a rapid increase in energy, but the physical gas volume is highest at the turbine outlet due to the expansion of the gases.