RESEARCHING OF RELATIONS FORMING BETWEEN PARAMETERS OF TWO-SPOOL TURBOFAN DYNAMIC MODEL AND OPERATION MODE

Abstract

Mathematical models are efficient instrument of engines and their automatic control systems designing. The main areas of the models application are simulation modeling of the controlled object at analysis, synthesis and semi-natural simulation, and also model-based engine controlling algorithms designing. In this case, a set of mathematical models is used that is derived from the initial (base) thermo-gas-dynamic model of working process, which is usually designed and supported by the engine designer. However, it not satisfies the requirement of real-time calculations when the model simulates the engine dynamics at operation with the real electronic hardware. Lacking of the above-listed shortcomings dynamic model of the engine is formed as a combination of simplified static and dynamic models. In this case, the dynamic model has a linear structure and characterizes dynamic relations in a local area close to the engine static characteristics that is represented as the static model. This dynamic model can be determined by linearization of the base thermo-gas-dynamic model. The base model is grounded on characteristics of the engine components, which are built using experimental results and a peace-linear interpolation. Due to the peace-linear interpolation of the characteristics, relations between the engine parameters have breaks, that causes errors in calculations, which are done using the model, and not corresponds to real processes in the engine. The drastic method to overcome this problem is a perfection of thermo-gas-dynamic model by smoothing the characteristics of components. However, this will mismatch the model, which is used by the ASC designer, and the base model of the engine designer. This paper considers approximation of the dynamic model coefficients, which are determined using the component-based thermo-gas-dynamic model with the peace-linear interpolation of the components’ characteristics. The research is aimed in improvement of the used linear dynamic models in a state space and automation of their forming for the engine automatic control systems quality increasing and synthesis acceleration.

Keywords

• газотурбинный двигатель
• автоматическое управление
• динамическая модель
• аппроксимация