Research ArticlePHYSICS

Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

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Science Advances  23 Feb 2018:
Vol. 4, no. 2, e1701571
DOI: 10.1126/sciadv.1701571
  • Fig. 1 Pool boiling experiments.

    (A) Test sections [field emission scanning electron microscopy (SEM)/3D profiler images]. (B) Experimental apparatus.

  • Fig. 2 Wetting characteristics depending on the environment.

    (A) Static contact angle (SCA) on the test sections, (B) comparison between the measured and estimated SCA on the test sections, and (C) wicking phenomena underneath the nucleate bubbles.

  • Fig. 3 Visualization of the liquid film underneath a nucleate bubble on a flat surface.
  • Fig. 4 Visualization of the liquid film underneath a nucleate bubble on microtextured surfaces.

    (A) X-ray images and (B) schematic diagram of the high roughness ratio (f = 1.62) surface; (C) x-ray images and (D) schematic diagram of the low roughness ratio (f = 1.08) surface.

  • Fig. 5 Visualization of the liquid film underneath massive bubbles on flat and microtextured surfaces.

    (A) Flat surface, (B) d40-g40 case (f = 1.62), (C) d80-g80 case (f = 1.31), (D) d40-g120 case (f = 1.15), and (E) d80-g240 case (f = 1.08).

  • Fig. 6 Comparison of the average liquid supply underneath a nucleate bubble and CHF enhancement on the test sections.

    (A) Specific process for calculating the average liquid flow rate underneath a nucleate bubble, (B) pool boiling curve, and (C) comparison between the CHF enhancement ratio and average liquid flow rate.

  • Table 1 Specific geometric features of the micropillar arrays.
    Casesd (μm)g (μm)p (μm)h (μm)f
    Flat1
    d40g40404080201.62
    d40g12040120160201.15
    d80g808080160201.31
    d80g24080240320201.08

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/2/e1701571/DC1

    section S1. Specific processes for the preparation of the test sections

    section S2. Synchrotron x-ray images

    section S3. Movies with x-ray images

    movie S1. Single bubble growing on flat surfaces.

    movie S2. Single bubble growing on a high roughness ratio surface.

    movie S3. Single bubble growing on a low roughness ratio surface.

    movie S4. Behavior of liquid-vapor interfaces on a flat surface (near CHF).

    movie S5. Behavior of liquid-vapor interfaces on a high roughness ratio surface (near CHF).

    fig. S1. The method used to fabricate the test sections.

    table. S1. Detailed information on the x-ray source.

    table. S2. Calculated average liquid flow rate underneath a nucleate bubble.

    Reference (46)

  • Supplementary Materials

    This PDF file includes:

    • section S1. Specific processes for the preparation of the test sections
    • section S2. Synchrotron x-ray images
    • section S3. Movies with x-ray images
    • Legends for movies S1 to S5
    • fig. S1. The method used to fabricate the test sections.
    • table S1. Detailed information on the x-ray source.
    • table S2. Calculated average liquid flow rate underneath a nucleate bubble.
    • Reference (46)

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    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.avi format). Single bubble growing on flat surfaces.
    • movie S2 (.avi format). Single bubble growing on a high roughness ratio surface.
    • movie S3 (.avi format). Single bubble growing on a low roughness ratio surface.
    • movie S4 (.avi format). Behavior of liquid-vapor interfaces on a flat surface (near CHF).
    • movie S5 (.avi format). Behavior of liquid-vapor interfaces on a high roughness ratio surface (near CHF).

    Files in this Data Supplement:

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