Radial inflow turbines for turbocharging - Basic principles

This topic is primarily addressed in the context of research and development of technologies specific to centripetal turbochargers for internal combustion engines on the websites[BM 4 570] and[BM 4 571].

The purpose of this article is to present the various terms used in the general description of turbomachines and the systems that utilize them. A brief description of the geometries specific to centripetal turbines is then provided, detailing their respective roles as well as the technological adaptations specific to the use of these machines within internal combustion engines.

The fundamental principles of thermodynamics as applied to turbomachines—principles that are specific to and necessary for the study of these small centripetal turbines—are reviewed from both an energy perspective (application of the two fundamental principles of thermodynamics to systems and definition of the various efficiency metrics used) and a kinematic perspective, including a review of the Navier-Stokes equations.

This article does not address the technological aspects of manufacturing, mechanical strength, and dimensional control, given the installation constraints and operating conditions within the engine environment. These aspects constitute proprietary know-how specific to each manufacturer, which must adapt the geometries to the displacement and architecture of each engine.

The article[BM 4 571] is intended to provide an initial approach to performance prediction using the equations proposed here.