과도액정기법을 이용한 열전달 측정 및 수치해석

Heat Transfer Measurement Using a Transient Liquid Crystal Technique and Numerical Anlysis

  • 홍철현 (부산대학교 기계설계전산화인력양성센터) ;
  • 이기백 (부산대학교 기계공학과, 기계기술연구소) ;
  • 양장식 (부산대학교 기계기술연구소)
  • 발행 : 2005.01.01

초록

A transient liquid crystal technique has become one of the most effective ways in measuring the local heat transfer coefficients on the entire surface. The key Point of this technique is to convert the inlet flow temperature into an exponential temperature profile using a mesh heater. In order to verify the validity of this technique. the heat transfer characteristics on the wall surface by a pair of longitudinal vortices is investigated experimently and numerically. A standard ${\kappa}-{\varepsilon}$ is used for the numerical analysis of turbulent flow field. It is found from experiment and numerical analysis that two peak values exist over the whole domain. as the longitudinal vortices move to the farther downstream. these peak values decrease and the dimensionless averaged Nusselt number with the lapse of time is maintained nearly at constant values. The experiment results obtained from the present experiment in terms of the transient liquid crystal technique are in good agreement with the numerical results. Therefore, the transient liquid crystal technique developed for the measurement of heat transfer coefficient is proved to be a valid method.

키워드

참고문헌

  1. Baughn, J. W., 'Liquid Crystal Methods for Studying Turbulent Fig. 14 Streamwise distributions of the spanwise averaged Nusselt number Heat Transfer'. International Journal of Heat and Fluid Flow, Vol. 16, No.5, pp. 364-375, 1995
  2. Chyu, M. K., Ding, H., Downs, J. P. and Soechting. F. O., 'Determination of Local Heat Transfer Coefficient Based on Bulk Mean Temperature Using a Transient Liquid Crystals Technique,' Experimental Thermal and Fluid Science, Vol. 18, pp. 142-149, 1998 https://doi.org/10.1016/S0894-1777(98)10016-X
  3. Ireland, P. T., Neely, A. J., Gillespie, D. R. H. and Robertson, A. J., 'Turbulent Heat Transfer Measurements Using Liquid Crystals,' International Journal of Heat and Fluid Flow, Vol. 20, pp. 355-367, 1999 https://doi.org/10.1016/S0142-727X(99)00030-2
  4. Gillespie, D. R. H., 'Intricate Internal Cooling Systems for Gas Turbine Blading,' Doctor of Philosophy Thesis, University of Oxford, 1996
  5. Moffat, R. J., 'Contributions to the Theory of Single-Sample Uncertainty Analysis,' Journal of Fluids Engineering, Vol. 104, June, pp. 250-260, 1982 https://doi.org/10.1115/1.3241818
  6. FLUENT users guide, version 5.6, 2001
  7. Hong, C. H., Yang, J. S., and Lee, K. B., 'An Experimental Study on the Effects of the Boundary Layer and Heat Transfer by Vortex Interactions (I),' Journal of KSME(B) , Vol. 24, No.2, pp. 288-297, 2000
  8. Kwon, S. I., Yang, J. S. and Lee, B. K., 'The Experimental Study of the Interaction Between the Flow and Temperature Field and a Boundary Layer Due to a Variety of the Height of a Vortex Generator.' Journal of KSME(B), Vol. 26, No. 1, pp. 82-93, 2002
  9. Yang, J. S., Lee, K. B., 'A Numerical Simulation of Longitudinal Vortex in Turbulent Boundary Layers,' Journal of KSME(B), Vol. 24, No.6, pp. 802-813, 2000
  10. Han, D. J., An experimental Study on the Interaction and Flow Characteristics of Longitudinal Vortex Pairs, Master of Science Thesis, Pusan National University, 1999
  11. Weshphal, R. V., Pauley, W. R. and Eaton, J. K., 'Interaction Between a Vortex and a Turbulent Boundary Layer-Part I: Mean Flow Evolution and Turbulence Properties,' NASA TM88361, 1987