Experimental Study of Wall Bounded Harbor Seal Whisker Inspired Pin Geometries

• Published in: AIAA SCITECH 2022 Forum
• Main Authors: Prasad, Anish, Ricklick, Mark
• Other Authors: 2368747
• Format: Text
• Language: unknown
• Published: Scholarly Commons 2022
• Subjects: convection cooling systems; heat transfer; Pin Geometries; Aerodynamics and Fluid Mechanics; Combustion; harbor seal
• Online Access: https://commons.erau.edu/publication/1778; https://doi.org/10.2514/6.2022-2225; https://commons.erau.edu/context/publication/article/2844/viewcontent/Scitech_Manuscript_2022.pdf

Conventional cylindrical/elliptical pins are one of the most widely used geometries in convection cooling systems and are used in the internal cooling of gas turbine blades and other applications, as they promote better heat transfer at the expense of large pressure losses and unsteadiness in the flow. The need to reduce pressure drop and maintain the heat transfer rates are a pressing requirement for a variety of industries to improve their cooling efficiency. One such prominent field of research is conducted in optimizing the design of pin geometries. In this study, a harbor seal whisker inspired geometry is being studied for their unsteady behavior in an internal cooling channel. The seal whisker geometry consists of streamwise and spanwise undulations which reduce the size of the wake and coherent structures shed from the body as a result of an added component of stream-wise vorticity along the pin surface. Also, the vortex shedding frequency becomes less pronounced, leading to significantly reduced lateral loading on the modified cylinder. Previous computational studies have shown that the bio-mimicked pin geometries break down the wake structure and there is a reduction in development of turbulent intensity downstream of the channel leading to a lower pressure loss. In this experimental study the thermal performance of the bio pins is compared against a conventional elliptical pin for a range of Reynolds numbers. From the results it is found that the bio pins in comparison to the elliptical pin performs on average 13% better in pressure drop at the cost of 4.5% in heat transfer. These findings are important to the gas turbine community as reduced penalties associated with cooling flows directly translate to improved efficiencies.