Numerical optimization, characterization, and experimental investigation of additively manufactured communicating microchannels

Kathryn L. Kirsch, Karen Ann Thole

    Research output: Contribution to journalArticle

    Abstract

    The degree of complexity in internal cooling designs is tied to the capabilities of the manufacturing process. Additive manufacturing (AM) grants designers increased freedom while offering adequate reproducibility of microsized, unconventional features that can be used to cool the skin of gas turbine components. One such desirable feature can be sourced from nature; a common characteristic of natural transport systems is a network of communicating channels. In an effort to create an engineered design that utilizes the benefits of those natural systems, the current study presents wavy microchannels that were connected using branches. Two different wavelength baseline configurations were designed; then each was numerically optimized using a commercial adjoint-based method. Three objective functions were posed to (1) minimize pressure loss, (2) maximize heat transfer, and (3) maximize the ratio of heat transfer to pressure loss. All baseline and optimized microchannels were manufactured using laser powder bed fusion (L-PBF) for experimental investigation; pressure loss and heat transfer data were collected over a range of Reynolds numbers. The AM process reproduced the desired optimized geometries faithfully. Surface roughness, however, strongly influenced the experimental results; successful replication of the intended flow and heat transfer performance was tied to the optimized design intent. Even still, certain test coupons yielded performances that correlated well with the simulation results.

    Original languageEnglish (US)
    Article number111003
    JournalJournal of Turbomachinery
    Volume140
    Issue number11
    DOIs
    StatePublished - Nov 1 2018

    Fingerprint

    Microchannels
    3D printers
    Heat transfer
    Turbine components
    Gas turbines
    Skin
    Reynolds number
    Fusion reactions
    Surface roughness
    Cooling
    Powders
    Wavelength
    Geometry
    Lasers

    All Science Journal Classification (ASJC) codes

    • Mechanical Engineering

    Cite this

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    abstract = "The degree of complexity in internal cooling designs is tied to the capabilities of the manufacturing process. Additive manufacturing (AM) grants designers increased freedom while offering adequate reproducibility of microsized, unconventional features that can be used to cool the skin of gas turbine components. One such desirable feature can be sourced from nature; a common characteristic of natural transport systems is a network of communicating channels. In an effort to create an engineered design that utilizes the benefits of those natural systems, the current study presents wavy microchannels that were connected using branches. Two different wavelength baseline configurations were designed; then each was numerically optimized using a commercial adjoint-based method. Three objective functions were posed to (1) minimize pressure loss, (2) maximize heat transfer, and (3) maximize the ratio of heat transfer to pressure loss. All baseline and optimized microchannels were manufactured using laser powder bed fusion (L-PBF) for experimental investigation; pressure loss and heat transfer data were collected over a range of Reynolds numbers. The AM process reproduced the desired optimized geometries faithfully. Surface roughness, however, strongly influenced the experimental results; successful replication of the intended flow and heat transfer performance was tied to the optimized design intent. Even still, certain test coupons yielded performances that correlated well with the simulation results.",
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    Numerical optimization, characterization, and experimental investigation of additively manufactured communicating microchannels. / Kirsch, Kathryn L.; Thole, Karen Ann.

    In: Journal of Turbomachinery, Vol. 140, No. 11, 111003, 01.11.2018.

    Research output: Contribution to journalArticle

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