TY - JOUR

T1 - Evaluation of the Rotor Temperature Distribution of an Automotive Turbocharger Under Hot Gas Conditions Including Indirect Experimental Validation

AU - Zeh, Christopher

AU - Willers, Ole

AU - Hagemann, Thomas

AU - Schwarze, Hubert

AU - Seume, Jorg

N1 - Funding Information: The research project was performed by the Institute of Tribology and Energy Conversion Machinery (ITR) at Clausthal University of Technology and the Institute of Turbomachinery and Fluid Dynamics (TFD) at Leibniz University Hannover. The FVV (Research Association for Combustion Engines eV) fully financed the project and an expert group under the direction of Dipl.-Ing. Uwe Tomm gave their extensive technical support. The authors gratefully acknowledge the assistance received from the FVV and from all those involved in the project.

PY - 2021/3

Y1 - 2021/3

N2 - While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFDmodel with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modeled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600 °C and the lubricant is supplied at a pressure of 300 kPa with 90 °C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

AB - While turbocharging is a key technology for improving the performance and efficiency of internal combustion engines, the operating behavior of the turbocharger is highly dependent on the rotor temperature distribution as it directly modifies viscosity and clearances of the fluid film bearings. Since a direct experimental identification of the rotor temperature of an automotive turbocharger is not feasible at an acceptable expense, a combination of numerical analysis and experimental identification is applied to investigate its temperature characteristic and level. On the one hand, a numerical conjugate heat transfer (CHT) model of the automotive turbocharger investigated is developed using a commercial CFD-tool and a bidirectional, thermal coupling of the CFDmodel with thermohydrodynamic lubrication simulation codes is implemented. On the other hand, experimental investigations of the numerically modeled turbocharger are conducted on a hot gas turbocharger test rig for selected operating points. Here, rotor speeds range from 64.000 to 168.000 rpm. The turbine inlet temperature is set to 600 °C and the lubricant is supplied at a pressure of 300 kPa with 90 °C to ensure practically relevant boundary conditions. Comparisons of measured and numerically predicted local temperatures of the turbocharger components indicate a good agreement between the analyses. The calorimetrically determined frictional power loss of the bearings as well as the floating ring speed are used as additional validation parameters. Evaluation of heat flow of diabatic simulations indicates a high sensitivity of local temperatures to rotor speed and load. A cooling effect of the fluid film bearings is present. Consequently, results confirm the necessity of the diabatic approach to the heat flow analysis of turbocharger rotors.

KW - CFD

KW - CHT

KW - Experimental

KW - Heat transfer

KW - Temperature

KW - Thermophysical

KW - Turbomachinery

UR - http://www.scopus.com/inward/record.url?scp=85107459269&partnerID=8YFLogxK

U2 - 10.1115/1.4049825

DO - 10.1115/1.4049825

M3 - Article

AN - SCOPUS:85107459269

VL - 143

JO - Journal of Engineering for Gas Turbines and Power

JF - Journal of Engineering for Gas Turbines and Power

SN - 0742-4795

IS - 3

M1 - 031022

ER -