Advanced Gas Turbine Cycles

There are a range of modifications that can be made to the simple gas turbine cycle in order to improve its overall efficiency. One of simplest, called recuperation, involves the use of heat from the gas turbine exhaust to heat the air from the compressor before it enters the combustion chamber. A second strategy called reheating involves splitting the power turbine into two parts, a high pressure turbine and a low pressure turbine. Hot gases exiting the high pressure turbine are further heated in a second combustor before entering the low pressure turbine. The inverse of this is intercooling, which is applied to the compressor by dividing it into two parts and cooling the air between the two. A final method of increasing overall efficiency is called mass injection. This usually involves injecting water or steam into the air at some stage during the gas turbine cycle.