Steady and Dynamic Performances of a Variable Geometry Gas Turbine

Abstract

A gas turbine which has a variable geometry free turbine can be expected to be improved not only in part load performance and acceleration capability but also in engine braking. Therefore it is suitable as the vehicular power plant from the above three view points. The control unit of such a gas turbine, however, becomes more complex than that of a conventional one. In the present paper, the steady and dynamic performances of such a gas turbine are investigated by the nomogram method and analog simulation respectively. The relations between part load performance, acceleration capability and nozzle angles are obtained, as well as the transient performance for a wide range of nozzle angles from the design value to engine braking. The results can be used as the basic data for the selection of turbine cycle, estimation of required component characteristics and design of controller at design phase.