Keywords

pin fin, supercritical carbon dioxide, high turbine inlet temperature, heat transfer, internal cooling, turbines

Abstract

To push the thermal efficiency of turbomachinery, the turbine inlet temperature must be raised, eventually reaching and surpassing the blade material thermal limits. Internal geometry, such as pin fin arrays, has been the go-to solution for higher thermal environments to remove heat from blades and vanes to prevent material failure. The industry standard for turbomachinery in energy generation uses the steam Rankine or the Brayton cycle. Classically, these cycles have used air as the operating fluid environment. Over the past decade, novel solutions have begun changing how we design cycles, with one promising solution emerging: the supercritical carbon dioxide (sCO2) power cycle. Promising higher cycle efficiency with a smaller footprint has quickly become an attractive alternative for power generation. Although thorough research of pin fin arrays as turbulators in the trailing edge of turbine blade internal design has been a focus of research for the past several decades, in the sCO2 novel working environment, the need to re-visit the heat transfer characterization of internal cooling is necessary. This study was executed two-fold, first numerically and then experimentally. The first objective of this paper is to explore the heat transfer characteristics of sCO2 as the cooling environment in a staggered pin fin array, defined within the supercritical phase, using steady RANS conjugate heat transfer. An adapted correlation for the Nusselt number was derived, dependent on the Reynolds number, to provide a stronger correlation than existing air data-derived correlations in the literature. Taking this numerically derived correlation, the second objective of this paper is to design and run a matching experimental geometry fabricated for testing at target operating conditions of 400 Celsius and 200 bar. This data was then processed in tandem with the numerical and available derived data in the literature for direct comparison.

Completion Date

2023

Semester

Fall

Committee Chair

Kapat, Jayanta

Degree

Master of Science (M.S.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

application/pdf

Identifier

DP0028099

URL

https://purls.library.ucf.edu/go/DP0028099

Language

English

Release Date

December 2026

Length of Campus-only Access

3 years

Access Status

Masters Thesis (Campus-only Access)

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Restricted to the UCF community until December 2026; it will then be open access.

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