Implementing the Exhaust Gas Temperature Control Logic in Off-Design Calculations of Gas Turbine

Gas turbine exhaust gas temperature control logic affects the steady state performance of the gas turbine and its bottoming-cycles and therefore, it should be included in the steady state analysis such as off-design calculations. The conventional method of implementing this control logic in the off-design calculation is to use an external loop in the solver algorithm that is numerically inefficient. This paper presents a new equation that is developed in order to apply the exhaust gas temperature control logic into the off-design calculations. This equation is a smooth function which makes it possible to be solved simultaneously with other equations and therefore, there is no need for the external loop any more. Consequently, the system of equations can be solved faster and more robust. The results of the simulations for a sample gas turbine show that the developed equation could apply the gas turbine control algorithm to off-design calculations accurately in a wide range of operating conditions.