Dynamic Model of a Two Shaft Heavy-Duty Gas Turbine With Variable Geometry

When designing a new plant, often it is necessary to make a simulation of the process in order to evaluate the dynamic behaviour of the whole system and the need of changes for its optimal performance. So dynamic models of the gas turbines used in the plant, either as mechanical drives or power generation, are needed. Actual gas turbines often incorporate variable geometry both in cold and hot sections. For example, the last generation of axial compressors are often equipped with variable geometry stator blades in order to achieve stable operation within the whole operating range, from start-up to full speed. As another example, power turbines sometimes have inlet guide vanes with a variable geometry in order to get a better efficiency at both partial load and speed, allowing the gas generator to run at the design speed. Disregarding to this, dynamic models which can be found in the actual literature deal with hot sections having a fixed geometry. This paper presents a dynamic model of two shaft heavy-duty gas turbines, with variable geometry in either cold and hot sections. It can be used to evaluate all the transient conditions such as start-up, shut-down and load variations in the normal operating range.Copyright © 1995 by ASME