Effects of Metal Surface Temperature on Deposition-Induced Flow Blockage in a Vane Leading Edge Cooling Geometry

In this study, the effect of the external metal temperature on flow blockage development in a simplified vane leading edge with impingement was assessed. Nominal 0–10 μm Arizona Road Dust particulate was fed into an 866K flow leading to the test article. An electric kiln was used to vary the external surface temperature of the article from 920K to 1262K. The time history of flow blockage development at a constant pressure ratio of 1.031 was recorded for each test. Mass-normalized blockage values at the end of the tests indicate a linear relationship with the external surface temperature, with values at 1262K more than double those at 920K. External surface temperatures were recorded throughout the test period via a surface mounted thermocouple and infrared thermography, indicating an increase in surface temperature proportional to the reduction in mass flow through the part. Localized flow temperature increases highlight areas where internal deposition is most aggressive during the dust injection process. Images of the deposit formations within the test article indicate regions where deposition has the strongest influence on flow blockage development, namely in and around the impingement holes. An analysis of the experiment was also performed using a computational simulation of the flow within the test article. Conjugate heat transfer simulations allow the internal flow and surface temperatures to be assessed for the various test conditions which, along with predicted particle rebound and deposit locations, lend insight into the mechanisms behind the deposition trends observed in the experiments.