We present experimental measurements and numerical simulations of convective heat transferperformance in the transitional rarefied regime for an isolated rectangular beam geometry. Experiments were performed using single crystalline silicon beam elements having width-to-thickness aspect ratios of 8.5 and 17.4. Devices were enclosed in a vacuum chamber and heated resistively using a DC power supply. A range of pressures corresponding to Knudsen numbers between 0.096 and 43.2 in terms of device thickness were swept, adjusting applied power to maintain a constant temperature of 50 K above the ambient temperature. Both parasiticelectrical resistance associated with the hardware and radiative exchange with the environment were removed from measured data, allowing purely convective heat flux to be extracted. Numerical simulations were carried out deterministically through solution of the Ellipsoidal Statistical Bhatnagar-Gross-Krook collision model of the Boltzmann equation. Results agree with experimental data, revealing a strong coupling between dissipated heat flux and thermal stresses within the flowfield as well as a nonlinear transition between the free-molecule and continuum regimes.


Copyright (2014) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in (A. Strongrich*, A. Alexeenko, “Experimental measurements and modeling of convective heat transfer in the transitional rarefied regime”, Proceedings of 29th International Symposium on Rarefied Gas Dynamics, Xi’an, China, July 13-19, 2014.) and may be found at http:// http://dx.doi.org/10.1063/1.4902664. The following article has been submitted to/accepted by [American Institute of Physics]. After it is published, it will be found at (http:// http://dx.doi.org/10.1063/1.4902664). Copyright (2014) A. Strongrich*, A. Alexeenko. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

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