Comparative fidelity analysis of turbofan engines masses mathematical models
The article presents comparative fidelity analysis of aviation gas turbine engines mass models accessible in open press. The authors of models are Torenbeek (Delft University of Technology, Nederland), Raymer (Conceptual Research Corporation, USA), Jenkinson (Loughborough University, UK), Svoboda (The University of Kansas, USA), Clavier (Cranfield University, UK and France), Guha (Indian Institute of Technology, India), Byerley (USAF Academy, USA) and Kuz'michev (Samara National Research University, Russia). Thermodynamic and dimensions parameters, used for analysis, of 77 modern bypass engines, differing significantly on working process parameters are presented in the article. Missing data for the above said base were obtained by the mathematical models identification method. Mass of each of 77 engines was determined by all eight models, and the obtained results were compared to the real engine mass. The analysis results revealed that some of the considered models such as Guha's, Byerley's, Jenkinson's and Clavier's models are applicable only for high-scale engines and their inaccuracy does not exceed 12%. The listed models calculate the small-scale engines weight with significant error. Moreover, the error value increases with the engine size reduction. This trend applies to all models without exception. For example, Kuzmichev's model has a total error of 6.3%, but for engines weighing less than 1500 kg the standard deviation approaches 20%. Based on the analysis presented in the article, it can be concluded that Svoboda's and Raymer's models can be employed for the aircraft conceptual design. Besides, these models can be applied at conceptual design stage. Torenbeek's and Kuzmichev's models are more detailed and account for cycle parameters. Thus, they may be employed for engine cycle optimization at design operational conditions.