The Camberline Optimization Procedure for Mixed Inflow Turbine Rotor

The primary function of a turbocharger is to compress air within the engine cylinder, thereby increasing mechanical power and enhancing overall combustion efficiency. This technology allows for the downsizing of engines, reducing both volume and saving fuel. Historically, mixed inflow turbines have been utilized as turbocharger drive mechanisms, with the rotor's geometry crucial for determining turbine efficiency. The aerodynamic profile of turbine blades, defined by the camberline, plays a pivotal role. These profiles are streamlined shapes with a thick, rounded leading edge and a thin trailing edge. Properly designed and aligned in the flow, they generate more lift than drag, significantly influencing rotor performance. This paper focuses on optimizing the camberline of mixed inflow rotor blades. Initially, the study verified the trailing edge optimization of type A blades (constant inlet blade angle), previously tested experimentally at Imperial College London. The optimization involved varying position coefficients using a fourth-degree Bezier polynomial mathematical model. Subsequently, improvements were made to the leading edge by adjusting the reference camber angle and the intersection of the leading and trailing edges. All geometric parameters in the meridian plane and deviation angle were held constant to maintain rotor casing consistency. The study utilized ANSYS CFX 15 to solve averaged Na-vier-Stokes equations governing flow through the turbine. This research underscores the significance of aerodynamic blade profiles and their geometric optimization in enhancing turbine efficiency. By refining trailing and leading edges, significant advancements in turbocharger performance can be achieved, contributing to more efficient and economical engine designs.