# Research on Real-Time Model of Turboshaft Engine with Surge Process
###### Abstract  
The main data source for the verification of surge detection methods still rely on test rigs of the compressor or the whole engine, which makes the development of models of the whole engine surge process an urgent need to replace the high-cost and high-risk surge test. In this paper, a novel real-time surge model based on the surge mechanism is proposed. Firstly, the turboshaft engine component level model (CLM) and the classic surge dynamic model, Moore-Greitzer (MG) model is established. Then the stability of the MG model is analyzed and the compressor characteristics in the classical MG model are extended to establish the extended MG model. Finally, this paper considers the coupling relationship of the compressor's rotor speed, mass flow and pressure between CLM and the extended MG model to establish the real-time model of the turboshaft engine with surge process. The simulation results show that this model can realize the whole surge process of the turboshaft engine under multiple operating states. The change characteristics of the rotor speed, compressor outlet pressure, mass flow, exhaust gas temperature and other parameters are consistent with the test data, which means that the model proposed can be further applied to the research of surge detection and anti-surge control. M +
Footnote †: journal: Medical Imaging  
doi: 10.3390/  
1980s. In 1976, [PERSON] [6] established a one-dimensional unsteady nonlinear model describing the dynamic process of surge and rotation stall of the axial compression system and defined the famous Greitzer-B parameter to distinguish the stall type of the system. In the 1980s, [PERSON] [7] established a two-dimensional rotating stall model and developed an unsteady model to predict the stall characteristics of multistage compressors by using the Fourier series to express the velocity disturbance. Based on the [PERSON] model and [PERSON] model, [PERSON] and [PERSON] [8] established an unsteady incompressible nonlinear model, the Moore-Greitzer (MG) model, which describes the dynamic process of the rotating stall and surge of the compression system in 1985. This model provides an important theoretical basis for the numerical simulation of the rotating stall and surge of the compressor system and the simulation of the dynamic stall characteristics of the compressor. Then, based on the MG model, [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON], etc. [9; 10; 11; 12; 13; 14; 15], improved the prediction accuracy of the MG model by modifying the hypothesis conditions. [PERSON], [PERSON] and [PERSON] [16; 17; 18] extended the MG model to the case of compressible flow. However, these researches' object is limited to the compressor or compression systems, and the compressor's characteristic is approximately expressed by a dimensionless cubic curve. In addition, the strong coupling between compressor and other parts of the engine, and the high complexity of matching in joint work are not considered. To study the dynamic characteristics of the engine's surge process, GE firstly carried out the numerical simulation of the surge phenomenon of the turbofan engine in the 1980s. Based on the consideration of the stall zone characteristics of the fan, the flameout limit and reverse flow characteristics of the combustion chamber, the whole engine model of turbofan engine with a large bypass ratio considering surge was established by using the volume dynamics [19; 20]. [PERSON] et al. [21] established the turbofan model of post-stall and surge which simulates the flow coefficient and pressure rise ratio of the compressor during surge by solving the two-dimensional Euler equations with source terms.