Enabling Self-propelled Condensate Flow During Phase-change Heat Rejection Using Surface Texturing

Transcription

1 Enabling Self-propelled Condensate Flow During Phase-change Heat Rejection Using Surface Texturing Presenter: Thomas L Estrange Contributors: (OSU) Shashank Natesh, Eric Truong, Dr. Vinod Narayanan (Auburn) Dr. Sushil Bhavnani November 14 th 2014 NASA Space Technology Research Grant - NNX13AC90G

2 Background FC-72 at1g with heat input of 0.93W/cm 2 t=0.0 ms t=17.8 ms t=35.0 ms FC-72 at ~0.03g with heat input of 1.17 W/cm 2 Small Ratchet Array (1 cm x 1 cm, 9 ratchets)

3 Motivation Combination of a condenser and boiler can create a pump-less thermal management loop

4 Hypothesis 1. Initial stage of condensation, t=t 1 2. Intermediate stage of condensation, t=t 2 >t 1 3. Intermediate stage of condensation, t=t 3 >t 2 4. Steady state condensate pumping

5 Characterization Methods Experimental Film development Condensation rates Numerical modeling (Ansys Fluent) used as comparison for experimental results

6 Ratchet Size Effect r = location of film interface length of wall τ = t computational t growth Pitch of 1 mm chosen for experiments

7 Orientation Effect Right side up Up side down An inverted orientation chosen for experiments

8 Experimental Facility

9 Results 9

10 Variation of Tilt Neg 7.5º tilt Zero tilt Pos 7.5º tilt Pos 15º tilt

11 Experimental vs Numerical Experimental Numerical

12 Experiment vs Simulation

13 Conclusions Experiment Brass ratchet experiments indicate preferential growth of condensate Good agreement between experimental and simulation growth rates Experimental results show no gravitational effects of film growth in the range of tilts tested Numerical Simulations indicate preferential motion towards the steep slope, validating hypothesis Rise to steeper slope seen up to 15 degree adverse inclination

14 Future Work Experimental Quantify condensation rates Complete morphological testing Validation of computational parametric study Numerical Parametric study of angle combination and pitch of the ratchet structure Simulate morphological study

15 ACKNOWLEDGEMENTS Condensation: STRO- ESI Grant Number NNX13AC90G Project Monitor: Eugene Ungar (NASA Johnson Space Center) Boiling: Grants NNX09AJ98G & NNX09AL63G Project Monitor: David Chao (NASA Glenn Research Center) Boiling: Grants & InterPACK/I CNMM 2015

16 Questions? 16

17 References Chen, C-H., Cai, Q., Tsai, C., Chen, C-L., Xiong, G., Yu, Y., Ren, Z., 2007, Dropwise Condensation on Superhydrophobic Surfaces with Two-Tier Roughness, Applied Physics Letters, Vol. 90, Carey, V. P., 2008, Liquid-Vapor Phase-Change Phenomena, Second Edition, Taylor and Francis group, New York. Rose, J. W., 2002, Dropwise Condendation Theory and Experiment: A Review, Proceedings of the Institution of Mechanical Eng., Vol. 216, Part A: Journal of Power and Energy, pp Kim, S., and Kim, K. J., 2011, Dropwise Condensation Modeling Suitable for Superhydrophobic Surfaces, ASME Journal of Heat Transfer, Vol. 133, Quere, D., 2005, Non-sticking Drops, Reports on Progress in Physics, Vol. 68, pp Narhe, R. D., and Beysens, D. A., 2006, Water Condensation on a Superhydrophobic Spike surface, Europhysics Letters, Vol. 75(1), pp Chen, X., Wu, J., Ma, R., Hua, M., Koratkar, N., Yao, S., and Wang, Z., 2011, Nanograssed Micropyramidal Architectures for Continuous Dropwise Condensation, Advanced Functional Materials, Vol. 21, pp Deng, T., Varanasi, K., Hsu, M., Bhate, N., Keimel, C., Stein, J., Blohm, M., 2009, Nonwetting of Impinging Droplets on Textured Surfaces, Applied Physics Letters, Vol. 94, Nakajima, A., Hashimoto, K., and Watanabe, T., 2001, Recent Studies on Super- Hydrophobic Films, Monatshefte fur Chemie, Vol. 132, pp Dietz, C., Rykaczewski, K., Federov, A. G., and Joshi, Y., 2010, Visualization of Droplet Departure on a Superhydrophobic Surface and Implications to Heat Transfer Enhancement During Dropwise Condensation, Applied Physics Letters, Vol. 97, Boreyko, J. B., and Chen, C-H., 2009, Self-propelled Dropwise Condensation on Superhydrophobic Surfaces, Physical Review Letters, Vol. 103, Miljkovic, N., Enright, R., Wang, E. N., 2012, Effect of Droplet Morphology on Growth Dynamics and Heat Transfer during Condensation on Superhydrophobic Nanostructured Surfaces, ACS Nano, Vol. 6[2], pp Cassie, A. B. D., and Baxter, S., 1944, Wettability of Porous Surfaces, Transactions of Faraday Society, Vol. 40, pp Duncombe, T. A., Erdem, E. Y., Shastry, A., Baskaran, R., and Bohringer, K. F., 2012, Thiagarajan, N., Kapsenberg, F., Narayanan, V., Bhavnani, S. H., and Ellis, C. D., 2012, Development of a heat sink with periodic asymmetric structures using gray-scale lithography and deep reactive ion etching, Electron Devices Letters, EDL , doi /LED , Vol. 33(7). Kapsenberg, F., Thiagarajan, N., Narayanan, V., and Bhavnani, S. H., 2012, Lateral Motion of Bubbles From Surfaces with Mini-ratchet Topography Modifications During Pool Boiling- Experiments and Preliminary Model, Itherm- Paper# 3062, San Diego, CA, May Thiagarajan, N., Kapsenberg, F., Narayanan, V., Bhavnani, S. H., and Ellis. C., 2011, On the Lateral Motion of Bubbles Generated from Reentrant Cavities Located on Asymmetrically Structured Surfaces, Interpack , Pacific Rim Technical Conference and Exposition on Packaging and Integration of Electronic and Photonic Systems, Portland, OR, July 2011.

18 Saturation pressure variation with time

19 Condenser Surface Morphologies I. Hydrophilic surface used with highly wetting fluid (FC-72) II. Hydrophobic surface used with moderately wetting fluid (Water) III. Hydrophilic- hydrophobic surface used with moderately wetting fluid (Water)

20 Surface Morphology II Initial stage of condensation, t=t 1 Intermediate stage of condensation, t=t 2 >t 1 Intermediate stage of condensation, t=t 3 >t 2 Renewal of dry surface for condensation

21 Surface Morphology III Initial stage of condensation, t=t 1 Intermediate stage of condensation, t=t 2 >t 1 Intermediate stage of condensation, t=t 3 >t 2 Renewal of surface for condensation