Doctoral Dissertations

Keywords and Phrases

Heat Transfer Enhancement; Helium Cooling; Nuclear Fusion; Optimization


"Heat transfer enhancement by means of internally modified geometries in tubes and channels is an important mechanism to improve the survivability of components in extreme high-heat flux environments. Various features such as ribs and fins are studied using computational fluid dynamics in both uniform and one-sided heating in tubes and rectangular channels respectively to determine the most effective geometries across a variety of different flow and heating conditions. This work examines heat transfer enhancement and rib geometry optimization to support experimental research for nuclear fusion applications. The project begins by designing and analyzing test sections supporting a helium flow loop assembled at Oak Ridge National Laboratory to analyze heat transfer enhancement for systems such as blanket and divertor components. This initial phase uses STAR-CCM+ to study a base set of literature-supported helium-cooled ribbed and fin geometries in tubes to examine their thermal and pressure drop performance relative to one another. The scope then broadens to using the STAR-CCM+ Design Manager tool to build a Pareto frontier of competing surface average Nusselt number and Fanning friction factor objectives. This study explores a variety of rib shapes and orientations in a rectangular air-cooled channel for optimal heat transfer performance and friction to determine the relationships between the different shapes, orientations, flow phenomena, and thermal performance due to the enhancements. Finally, this project concludes by using optimization techniques to perform single objective optimization of overall heat transfer enhancement on ribs in helium-cooled tubes for the helium flow loop conditions to improve knowledge surrounding geometry enhancement for fusion blanket research"--Abstract, p. iv


Schlegel, Joshua P.

Committee Member(s)

Castano, Carlos C.
Frimpong, Samuel P.
Lumsdaine, Arnold
Mueller, Gary E.
Youchison, Dennis L.


Nuclear Engineering and Radiation Science

Degree Name

Ph. D. in Nuclear Engineering


Missouri University of Science and Technology

Publication Date

Fall 2022


xviii, 144 pages

Note about bibliography

Includes_bibliographical_references_(pages 139-143)


© 2022 Monica Lynn Gehrig, All Rights Reserved

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 12192