Nanofibers of polypropylene were produced by a modified melt-blowing method. The manufacturing method and thermal characteristics of fabricated nonwoven-fabric nanofibers were studied. Apparent thermal conductivity was measured as an evaluation of adiabatic properties, and a prediction model was developed with computational fluid dynamics (CFD) based on a one-dimensional computer-aided engineering method. In addition, we attempted to evaluate true thermal conductivity in consideration of lateral heat dissipation during measurement by thickness. Consequently, we determined the influence of the fiber diameter and thickness of the nonwoven fabric on the thermal conductivity and demonstrated that the proposed CFD model was effective for estimating the characteristics of the thermal conductivity of the nonwoven fabric.

1. [1] E. Cuce, S. B. Riffat, and C.-H. Young, “Thermal insulation, power generation, lighting and energy saving performance of heat insulation solar glass as a curtain wall application in Taiwan: A comparative experimental study,” Energy Conversion and Management, Vol.96, No.15, pp. 31-38, 2015.
2. [2] R. Ginevičius, V. Podvezko, and S. Raslanas, “Evaluating the alternative solutions of wall insulation by multicriteria methods,” J. of Civil Engineering and Management, Vol.14, Issue 4, pp. 217-226, 2008.
3. [3] M. A. Donmez, M. H. Hahn, and J. A. Soons, “A Novel Cooling System to Reduce Thermally-Induced Errors of Machine Tools,” CIRP Annals, Vol.56, Issue 1, pp. 521-524, 2007.
4. [4] M. Weck, P. Mckeown, R. Bonse, and U. Herbst, “Reduction and Compensation of Thermal Errors in Machine Tools,” CIRP Annals, Vol.44, Issue 2, pp. 589-598, 1995.
5. [5] T. Okazaki, K. Oikawa, S. Sakatani, and T. Kurashiki, “Study on the rigidity improvement of non-woven composite aerogel insulation material according to the non-woven fabric oriented design,” Trans. of the JSME, Vol.82, No.842, p. 16-00135, 2016 (in Japanese).
6. [6] J. O. Vasseur, .B Djafari-Rouhani, L. Dobrzynski, M. S. Kushwaha, and P. Halevi, “Complete acoustic band gaps in periodic fibre reinforced composite materials: the carbon/epoxy composite and some metallic systems,” J. of Physics: Condensed Matter., Vol.6, No.42, pp. 8759-8770, 1994.
7. [7] C. J. Ellison, A. Phatak, D. W. Giles, C. W. Macosko, and F. S. Bates, “Melt blown nanofibers: Fiber diameter distributions and onset of fiber breakup,” Polymer, Vol.48, No.11, pp. 3306-3316, 2007.
8. [8] F. Zuo, D. H. Tan, Z. Wang, S. Jeung, C. W. Macosko, and F. S. Bates, “Nanofibers from melt blown fiber-in-fiber polymer blends,” ACS Macro Letters, Vol.2, No.4, pp. 301-305, 2013.
9. [9] W. Wu, E. Aoyama, T. Hirogaki, M. Ikegaya, T. Echizenya, and H. Sota, “Polishing characteristics of buff machining using non-woven nanofiber fabric,” J. of the Japan Society for Abrasive Technology, Vol.61, No.11, pp. 600-606, 2017 (in Japanese).
10. [10] W. Wu, L. Ma, E. Aoyama, T. Hirogki, M. Ikegaya, T. Echizenya, and H. Sota, “Study on production of flocculating nanofiber and its application for ultra-precision abrasive machining,” Advances in Materials and Processing Technologies, Vol.4, No.3, doi: 10.1080/2374068X.2018.1452113, 2018.
11. [11] W. Wu, E. Aoyama, T. Hirogaki, K. Urabe, and H. Sota, “Development of Nanofibre Abrasive Buffing Pad Produced with Modified Melt Blowing Mehtod,” Int. J. of Abrasive Technology, Vol.9, No.1, pp. 31-48, 2019.
12. [12] W. Wu, T. Hirogaki, E. Aoyama, M. Ikegaya, and H. Sota, “Investigation of Oil Adsorption Performance of Polypropylene Nanofiber Nonwoven Fabric,” J. of Engineering Materials and Technology, Vol.141, No.2, p. 021004-1-8, 2019.
13. [13] W. Wu, E. Aoyama, T. Hirogaki, M. Ikegaya, T. Echizenya, and H. Sota, “Investigation of production on nano fiber non-woven fabric and its base features for applications,” Trans. of the JSME, Vol.92, pp. 130-133, 2017 (in Japanese).
14. [14] T. Hatakeyama, “Standards of heat dissipation of printed circuit boards of JPCA,” J. of The Japan Institute of Electronics Packaging, Vol.21, No.2, pp. 126-129, 2018 (in Japanese).
15. [15] S. Kondoh, A.Tezuka, and H. Komoto, “Design process model for 1DCAE (1st report): A mathematical formulation of knowledge modification process through a series of consultants with multiple models,” Trans. of JSCES, Paper No.20140002, 2014 (in Japanese).
16. [16] K. Ohtomi, “KANSEI Modeling Based on 1DCAE Concept,” Proc. of 11th Int. Modelica Conf., No.118, pp. 811-815, doi: 10.3384/ecp15118811, 2015.
17. [17] R. Abdullah, V. Agranat, M. Malin, and I. Pioro, “CFD prediction of mixed-convection heat transfer in supercritical water in a bare tube,” Proc. of the Int. Conf. on Nuclear Engineering (ICONE), ICONE23-1108, 2015.
18. [18] A. Agah and F. D. Ardejani, “A CFD model for prediction of the role of biomass growth and decay on the aerobic biodegradation of BTEX fate and transport in an unconfined aquifer system,” Int. J. Environ. Res., Vol.9, No.3, pp. 933-942, 2015.
19. [19] The Japan Society of Mechanical Engineers, “JSME data book: Heat transfer,” 4th Edition, 1986 (in Japanese).
20. [20] P. W. Gibson, C. Lee, F. Ko, and D. R. Reneker, “Application of Nanofiber Technology to Nonwoven Thermal Insulation,” J. of Engineered Fibers and Fabrics, Vol.2, Issue 2, pp. 32-40, 2007.
21. [21] T. Fujimoto and M. Niwa, “Experimental study on effective thermal conductivity of fiber assembly (Part 1: Evaluation of anisotropic effective thermal conductivity and role of radiative heat transfer),” J. of Textile Engineering, Vol.42, No.2, pp. 63-71, 1989 (in Japanese).