Session: Poster Session

Paper Number: 158555

Experimental Investigation on Thermohydraulic Performance of Additively Manufactured Rib Turbulators 

A common method of enhancing internal heat transfer is the use of turbulence promoters to induce flow separation. Rib turbulators are the most broadly studied of these surface features, offering significant design flexibility and varied augmentation ranges. The present study experimentally investigated how additive manufacturing impacted thermohydraulic performance of cooling channels, lined with rib turbulators on two opposite walls. A myriad of test samples with ribbed channels were designed for heat exchanger applications and manufactured by Direct Metal Laser Sintering (DMLS). The rib turbulators varied by height, configuration, and cross-section with some test coupons altering channel aspect ratios. Most rib cross-sections were modified from traditional geometries to include a 45-degree downskin support surface, limiting potential for print failures. An additional coupon was produced with empty channels to serve as a control case and isolate the potential impacts of surface roughness. Pressure loss and bulk heat transfer measurements were performed on samples with flow conditions in both the transitional and the turbulent regimes. Optical profilometry revealed that the samples printed with relatively low surface roughness for additive components, and large channel hydraulic diameters relative to the roughness further reduced the impact on friction factor and heat transfer augmentation. Computed Tomography (CT) scanning data helped determine the as-manufactured hydraulic diameters and rib geometries for comparison with the intended designs. The performance of the rib turbulators followed or improved upon trends of the smooth rib geometries that served as the design basis for this study.

Presenting Author: Winfield Horning The Pennsylvania State University

Presenting Author Biography: Winfield Horning is a graduate student at The Experimental and Computational Convection
Laboratory at the Pennsylvania State University. He is researching the effects of surface
features on the thermohydraulic performance of additively manufactured heat exchangers. His
interests extend into the characterization and impacts of surface roughness from additive
manufacturing.

Authors:

Winfield Horning The Pennsylvania State University
Stephen Lynch The Pennsylvania State University
Karen Thole The Pennsylvania State University