A comprehensive aerodynamic-thermal-mechanical design method for fast response turbocharger applied in aviation piston engines

Abstract

Limited by the poor transient response performance of turbochargers, the dynamic performance of aviation piston engines tends to deteriorate. In a bid to enhance the turbocharger's acceleration capabilities, this study scrutinizes various factors impacting its performance. Based on the operational principles and transient response process of the turbocharger, three types of inertia—namely, aerodynamic inertia (ADI), thermal inertia (TI), and mechanical inertia (MI) — are identified and addressed for design. To begin, this paper pioneers the innovative definition of a method for evaluating the transient response performance of the turbocharger. This method incorporates the introduction of an ADI parameter, inspired by the definition of MI. Subsequently, a thin-walled volute design with a low Biot number and a lightweight turbine impeller is introduced to reduce the turbocharger's TI and MI. The simulation results of the flow field distribution within the volute and diffuser demonstrate the comprehensive design method's effectiveness in improving gas pressure and temperature distributions in these components. Notably, the pressure distribution fluctuation in the constant moment-of-momentum volute (CMV) is 62.8% lower than that in the constant velocity moment volute (CVMV). The low-TI thin-walled volute not only enhances the turbocharger's response speed but also reduces its weight by approximately 40%. The impact of three types of inertia on the engine's response speed is quantified as follows: ADI (94%) > MI (5%) > TI (1%). This conclusion has been verified through test results of both the turbocharger and the engine. This design method not only significantly improves the turbocharger's response performance but also offers valuable insights for the optimal design of other blade mechanical systems.