Session: 12-08: Film Cooling Under Engine Like Conditions

Paper Number: 152999

The Relative Effects of Internal Reynolds Number and Advective Capacity Ratio on the Coolant Warming Factor 

Conjugate heat transfer experiments to predict turbine component temperatures involve matching the Biot number of the experimental condition to that of the engine condition. Done properly, such an experiment could yield an overall effectiveness distribution that is relevant to the engine condition. However, the underlying theory suggests that the coolant warming factor, χ, must also be matched to achieve the desired effect, and the requirements to do so have been neglected in the literature. Additionally, very little success has been achieved in determining the theoretical requirements to match χ. In this work, we develop these theoretical requirements, apply them for when coolant flow is scaled by the Reynolds number ratio and advective capacity ratio, and test them by comparing computational results against prior experimental data. The findings from this study indicate a strong influence of the thermal conductivity of the coolant. Interestingly, a thermal conductivity inappropriately large will have opposite effects on the coolant warming factor depending on which coolant flow rate parameter is used to characterize the coolant flow. Knowledge of the subtle requirements to properly replicate the coolant warming factor in an experiment will allow turbine designers to achieve more accurate surface temperature predictions through properly designed experiments.

Presenting Author: John Di Lella Air Force Institute of Technology

Presenting Author Biography: John Di Lella is a developmental engineer in the US Air Force and recently earned his masters degree at the Air Force Institute of Technology.

Authors:

John Di Lella Air Force Institute of Technology
Connor Wiese Air Force Institute of Technology
James L. Rutledge Air Force Institute of Technology