Investigation of compressible internal flow mechanisms and thermofluid interactions in centrifugal compressors through advanced hub-to-shroud computational fluid dynamics for diesel engine turbocharger performance

Abstract

This study presents a detailed computational investigation of internal flow dynamics within a centrifugal compressor using advanced computational fluid dynamics techniques. The primary objective is to elucidate the thermodynamic interactions and flow structures influencing compressor performance across various operating conditions. High-fidelity simulations are performed on a single-passage configuration at a fixed rotational speed of 80 000 rpm, capturing critical phenomena such as flow separation, vortex leakage, recirculation zones, and secondary flows. A comprehensive hub-to-shroud analysis reveals the spatial evolution of pressure fields, temperature gradients, and turbulence characteristics, highlighting distinct aerodynamic regimes: uniform flow with minimal gradients near the hub (20% span), balanced effects at mid-span (50%), and intensified flow disturbances and thermal gradients near the shroud (80%). The results emphasize the dominance of secondary flows and separation, particularly under off-design conditions, with complex helical structures and recirculation zones becoming more prominent at higher pressure ratios. Blade loading analysis further indicates that the leading-edge and tip regions are most susceptible to adverse pressure gradients and flow detachment. These findings underscore the critical importance of geometric optimization in mitigating loss-inducing flow features and improving compressor efficiency. The outcomes offer valuable insights for enhancing the performance and reliability of compressors in diesel engine applications and contribute to the broader field of high-performance turbomachinery design.