EFFECTS OF POST-PROCESSING ON PRESSURE DROP AND HEAT TRANSFER CHARACTERISTICS OF ADDITIVELY MANUFACTURED COOLING CHANNELS

Open Access
Author:
Orth, Carolyn Ann
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr. Karen Thole, Thesis Supervisor
  • Dr. Hosam Fathy, Honors Advisor
Keywords:
  • additive manufacturing
  • heat transfer
  • pressure drop
  • cooling channels
  • surface roughness
Abstract:
Additive manufacturing (AM) techniques such as laser powder bed fusion (L-PBF) are increasingly being used in various industries due to their numerous advantages. However, the use of AM is limited by the defects introduced by the process, such as surface roughness. Surface roughness negatively affects the pressure loss and heat transfer of internal cooling channels in gas turbine engine components. There are several post-processing methods discussed in the literature to reduce the surface roughness of AM components. However, these methods are usually applied to external surfaces and are ineffective for internal channels. In this study, L-PBF Inconel 718 samples and an L-PBF test coupon with internal cooling channels of material similar to Inconel 939 were post-processed using various heat treatment and/or hipping parameters to examine the impact on surface finish. While the Inconel 718 samples experienced no measurable surface roughness reduction, the heat treatment and hipping processes significantly improved the surface finish of the Inconel 939 test coupon channels. Additionally, the surface roughness reduction of the coupon channels resulted in a decrease in pressure loss across the channels for the same heat transfer augmentation, compared to the as-manufactured channels.