VASCULAR STRUCTURES FOR SMART FEATURES: SELF-COOLING AND SELF-HEALING

Abstract

Here we show how smart features of self-cooling and self-healing can be gained to mechanical systems with embedded vascular structures. Vascular structures mimic the circulatory system of animals. Similar to blood distribution from heart to the animal body, vascular channels provide the distribution of coolant and/or healing agent from a point to the entire body of a mechanic system. Thus the mechanic system becomes capable of cooling itself under unpredictable heat attacks and capable of healing itself as cracks occur due to applied mechanical loads. These smart features are necessary for advanced devices, equipment and vehicles. The essential design parameter is vascularization in order to provide smart features. There are distinct configurations for vascularization such as radial, tree-shaped, grid and hybrids of these designs. In addition, several theories are available for the shape optimization of vascular structures such as fractal theory and constructal theory. Unlike fractal theory, constructal theory does not include constraints based on generic algorithms and dictated assumptions. Therefore, constructal theory approach is discussed in this paper. This paper shows how smart features can be gained to a mechanical system while its weight decreases and its mechanical strength increases simultaneously.

Keywords

• Vascular,Constructal,Smart-features,Self-cooling,Self-healing

References

1. [1] Bejan, A., Advanced engineering thermodynamics, 1997, 2nd ed., Wiley, New York.
2. [2] Bejan, A. and Lorente, S., Design with constructal theory, 2008, Wiley, Hoboken.
3. [3] Bejan, A. and Zane, J.P., Design in nature: how constructal law governs evolution in biology, physics, technology, and social organization, 2012, Doubleday, New York.
4. [4] Bejan, A., Shape and structure, from engineering to nature, 2000, Cambridge University Press, Cambridge.
5. [5] Pfeifer, P. and Avnir, D., Chemistry in noninteger dimensions between 2 and 3.1. fractal theory of heterogeneous surfaces, J. Chem. Phys., 1983, 79(7), pp. 3558–3565.
6. [6] Mandelbrot, B.B., The fractal geometry of nature, 1983, Henry Holt and Company.
7. [7] Bejan, A. and Maden, J.H., The constructal unification of biological and geophysical design, Phys. Life Rev., 2009, 6(2), pp. 85–102.
8. [8] Bejan, A. and Lorente, S., Constructal law of design and evolution: physics, biology, technology and society, J. Appl. Phys., 2013, 113, 151301.

9. [9] White, S.R., Sottos, N.R., Moore, J., Geubelle, P., Kessler, M., Brown, E., Suresh, S. and Viswanathan, S., Autonomic healing of polymer composites, Nature, 2001, 409, pp. 794–794.
10. [10] Brown, E.N., Sottos, N.R. and White, S.R., Fracture testing of a self-healing polymer composite, Experiment. Mech., 2002, 42(4), pp. 372–379.
11. [11] Toohey, K.S., Sottos, N.R., Lewis, J.A., Moore, J.S. and White, S.R., Self-healing materials with microvascular networks, Nature Mater., 2007, 6, pp. 581–585.
12. [12] Coope, T.S., Wass, D.F., Trask, R.S. and Bond, I.P., Repeated self-healing of microvascular carbonfibre reinforced polymer composites, Smart Mater. Struct., 2014, 23(11), 115002.
13. [13] White, S.R., Moore, J.S., Sottos, N.R., Krull, B.P., Santa Cruz, W.A., Gergely, R.C.R., Restoration of large damage volumes in polymers, Science, 2014, 344, pp. 620–623.
14. [14] Kang, S., Jones, A.R., Moore, J.S., White, S.R. and Sottos, N.R., Microencapsulated carbon black suspensions for restoration of electrical conductivity, Adv. Funct. Mater., 2014, 24, pp. 2947–2956.
15. [15] Odom, S.A., Tyler, T.P., Caruso, M.M., Ritchey, J.A., Schulmerich, M.V., Robinson, S.J., Bhargava, R., Sottos, N.R., White, S.R., Hersam, M.C. and Moore, J.S., Autonomic restoration of electrical conductivity using polymer-stabilized carbon nanotube and grapheme microcapsules, Appl. Phys. Lett., 2012, 101, 043106.
16. [16] Lee, J., Kim, Y., Lorente, S. and Bejan A., Constructal design of a comb-like channel network for self-healing and self-cooling, Int. J. Heat Mass Transfer, 2013, 66, pp. 898–905.
17. [17] Lorente, S. and Bejan, A., Vascularized smart materials: designed porous media for self-healing and self-cooling, J. Porous Media, 2009, 12(1), pp. 1–18.
18. [18] Therriault, D., White, S.R. and Lewis, J.A., Chaotic mixing in three-dimensional microvascular networks fabricated by direct-write assembly, Nature Mater., 2003, 2(4), pp. 265–271.
19. [19] Cetkin, E., Lorente, S. and Bejan, A., Vascularization for cooling and mechanical strength, Int. J. Heat Mass Transfer, 2011, 54, pp. 2774–2781.
20. [20] Cetkin, E., Lorente, S. and Bejan, A., Vascularization for cooling a plate heated by a randomly moving source, J. Appl. Phys., 2012, 112, 084906.
21. [21] Wang, K.-M., Lorente, S. and Bejan, A., Vascular materials cooled with grids and radial channels, Int. J. Heat Mass Transfer, 2009, 52, pp. 1230–1239.
22. [22] Cetkin, E., Lorente, S. and Bejan, A., Hybrid grid and tree structures for cooling and mechanical strength. J. Appl. Phys., 2011, 110, 064910.
23. [23] Rocha, L.A.O., Lorente, S. and Bejan, A., Tree-shaped vacular wall designs for localized intense cooling, Int. J. Heat Mass Transfer, 2009, 52, pp. 4535–4544.
24. [24] Kim, S., Lorente, S. and Bejan, A., Vascularized materials with heating from one side and coolant forced from the other side, Int. J. Heat Mass Transfer, 2007, 50, pp. 3498–3506.
25. [25] Soghrati, S., Thakre, P.R., White, S.R., Sottos, N.R. and Geubelle, P.H., Computational modelling and design of actively-cooled microvascular materials, Int. J. Heat Mass Transfer, 2012, 55, pp. 5309–5321.
26. [26] Cetkin, E., Constructal structures for self-cooling: microvascular wavy and straight channels, J. Thermal Engineering, 2015, 1, pp. 166–174.
27. [27] Wang, K.-M., Lorente, S. and Bejan, A., Vascular structures for volumetric cooling and strength, J. Appl. Phys., 2010, 107, 044901.
28. [28] Rocha, L.A.O., Lorente, S. and Bejan, A., Vascular design for reducing hot spots and stresses, J. Appl. Phys., 2014, 115, 174904.
29. [29] Cetkin, E., Lorente, S. and Bejan, A., Vascularization for cooling and reduced thermal stresses, Int. J. Heat Mass Transfer, 2015, 80, pp. 858–864.
30. [30] Bejan, A. and Lorente, S., The constructal law and evolution of the design in nature, Phys. Life Rev., 2011, 8, pp. 209–240.
31. [31] See www.comsol.com for information about Comsol Multiphysics.
32. [32] Bhattacharje, S. and Grosshandler, W.L., The formation of a wall jet near a high temperature wall under microgravity environment, ASME HTD, 1988, 96, pp. 711–716.
33. [33] Petrescu, S., Comments on the optimal spacing of parallel plates cooled by forced convection, Int. J. Heat Mass Transfer, 1994, 34, p. 1283.
34. [34] Yenigun, O. and Cetkin, E., Constructal tree-shaped designs for self-cooling, Int. J. Heat Technology, 2016, 34, pp. 173–178.
35. [35] Cetkin, E., Constructal vascular structures with high-conductivity inserts for self-cooling, J. Heat Transfer, 2015, 137, 111901.