In this paper, the results of an experimental study of the time-resolved structure of a thermal boundary layer in a pulsating channel flow are presented. The developing laminar regime is investigated. Two techniques were used for time-resolved temperature measurements: a nonintrusive, pure-rotational CARS method and cold-wire anemometry. Results are presented for differing degrees of flow reversal, and the data show that the primary impact of reversed flow is an increase in the instantaneous thermal boundary-layer thickness and a period of decreased instantaneous Nusselt number. For the developing laminar parameter space spanned by the experiments, time-averaged heat-transfer enhancements as high as a factor of two relative to steady flow are observed for nonreversing and partially reversed pulsating flows. It is concluded that reversal is not necessarily a requirement for enhancement.
Time-Resolved Thermal Boundary-Layer Structure in a Pulsatile Reversing Channel Flow
Contributed by the Heat Transfer Division for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received by the Heat Transfer Division April 21, 2000; revision received February 5, 2001. Associate Editor: M. Hunt.
Kearney, S. P., Jacobi, A. M., and Lucht, R. P. (February 5, 2001). "Time-Resolved Thermal Boundary-Layer Structure in a Pulsatile Reversing Channel Flow ." ASME. J. Heat Transfer. August 2001; 123(4): 655–664. https://doi.org/10.1115/1.1372317
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