Steady-state and starting performance study of intercooling turbofan engine based on validation models

To address the thrust deficiency of gas turbine engines at Mach above 2, this paper plans to develop a verification engine for a high-speed turbine by adding an intercooler to a mature engine. In order to assess the feasibility of the verification engine and the needs of the intercooler design, a study of the performances of the intercooling engine was carried out by relying on the component level performance model. The model has been validated rely on test data. The average error of the validated model was found to be less than 2 %. Based on the validation model, the effect of intercooler installation on component matching and overall machine performance was analyzed, focusing on the effect of installation loss on ground starting performance. The results show that at an altitude of 25 km and Mach of 2.3, with a cooling airflow of 80 K, engine thrust increased by 33.7 %. Meanwhile, the compressor outlet total temperature remained below 790 K. At low-speed state, the results indicate that the loss in the intercooler's hot duct reduces the low-pressure rotor speed, leading to a significant decrease in engine thrust, while the bypass losses may cause fan surge. To resolve these issues, the study suggests activating the intercooler during ground operation to improve engine performance. The results show that, with a 2 % total bypass pressure loss, activating the intercooler increases thrust and keeps the fan surge margin above the safety limit. When the bypass loss increases to 5 %, it is necessary to adjust the A8 to ensure the surge margin remains above 10 %. This paper evaluates the effect of intercooler losses on the engine's starting process. Using the validated model, the starting performance of engines with 2 % and 5 % bypass losses was assessed at different temperatures. The results show that, with 2 % bypass loss, the engine can achieve rapid and stable starting. However, when the loss increases to 5 %, there is a risk of fan surge during start-up. Ultimately, the results of the study proved the feasibility of the program for intercooled engines and created traction requirements for intercooler design.