Session: 20-01 Radial Turbocompressors Analysis

Paper Number: 80820

80820 - Advanced Thermal Profiling of Turbocharger Compressor Wheels Using Phosphorescence Thermal History Coatings 

Compliance towards future emissions legislations requires internal combustion engines to utilize highly efficient combustion system (i.e. Miller cycle). Such combustion systems often come along with an increased boost pressure requirement leading towards increased mechanical stress on turbocharger components. This is especially the case for compressor wheels due to an increased speed and temperature loading. To offer cost competitive products turbocharger manufacturers must further exploit the limits of conventional state-of-the-art materials used in automotive turbochargers and refine development processes of their components. Knowing the exact boundary conditions under which turbocharger components are working is essential whereby a high uncertainty is the actual material temperature components experience under real operating conditions.

Temperature measurements are usually conducted during turbomachinery durability tests to validate thermodynamic models and assess components’ lifetime. Temperature measurement techniques typically include thermocouples, thermal paints and optical sensors. However, the former methods are limited mostly to non-moving components and can only provide point measurements, and the latter can only offer low resolution data for short durations and involves highly toxic materials. Thermal History Paint & Coating technology developed by Sensor Coating Systems (SCS) offers a unique solution for thermal mapping in harsh environments. The technology is based on a phosphor material which is applied as a paint or coating on the surface of the components to be measured. The components are then exposed to high temperatures during pre-defined tests. The luminescent properties of the coating material are changing permanently depending on the maximum exposure temperature during the test. Then, after the process the maximum temperature can be calculated using a calibration method. The THP/C luminescent properties are then measured in multiple locations using a laser-based instrumentation system and a robotic arm. High-resolution thermal maps directly on the 3D CAD models of the component can then be provided.

For this application the THP material has been applied for first time on the surface of three turbocharger compressor wheels that were tested under different cooling conditions. The duration of the test was about 15 minutes in steady state condition conducted in a hot gas stand environment. The THP material showed excellent durability during the test at high circumferential speeds above 580 m/s. More than 2,000 temperature measurements were obtained on pre-selected locations on the surface of three wheels, digitised and plotted on the 3D CAD model of the components for visual comparison. The obtained temperature profiles were in good agreement with expectations and relative temperatures matched respective cooling regimes. The test indicates that THP can be used on components with complex geometries such as turbocharger compressor wheels and temperatures as low as 120 °C have been resolved for the first time. The information obtained in this work can be used to improve the interpretation of the durability test and hence accelerate new product release.

Presenting Author: Silvia Araguas Sensor Coating Systems

Presenting Author Biography: N/A

Authors:

Solon Karagiannopoulos Sensor Coating Systems
Martin Rode IHI Charging Systems International GmbH
David Peral Sensor Coating Systems
Daniel Castillo Sensor Coating Systems
Silvia Araguas Sensor Coating Systems
Kieron Rai Sensor Coating Systems
Ryosuke Inomata IHI Charging Systems International GmbH
Georgios Iosifidis IHI Charging Systems International GmbH
Jörg Feist Sensor Coating Systems