Thermal modeling with solid/liquid phase change of the thermal energy storage experiment
A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.
Modeling Cyclic Phase Change and Energy Storage in Solar Heat Receivers
Numerical results pertaining to cyclic melting and freezing of an encapsulated phase-change material (PCM), integrated into a solar heat receiver, have been reported. The cyclic nature of the present problem is relevant to latent heat thermal energy storage systems used to power solar Brayton engines in space. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's ground test demonstration (GTD) system was developed and results compared with available experimental data. Multiconjugate effects such as the convective flow of a low Prandtl number fluid, conduction in the PCM, containment tube, and working fluid conduit were accounted for in the model. An ideal-body thermal radiation model was also included to quantify reradiative effects inside the receiver along with losses through the aperture and receiver shell. A high-temperature eutectic mixture of LiF-CaF 2 was used as the PCM and a mixture of He/Xe was used as the working fluid. A modified version of the computer code HOTTube was used to generate results for comparisons with GTD experimental data in both subcooled and two-phase regimes. While qualitative trends were in close agreement for the balanced-orbit modes, excellent quantitative agreement was observed for steady-state modes.
Application of 2μm Tm Laser on Biomedicine
Continuous wave Thulium laser emits at wavelength of 2.0 mm, which is well suited for tissue ablationand thermally stimulating cutaneous nerves due to its high absorption by water. 2 mm laser can be transmitted suffi-ciently by common quartz fibers and it is safe for eyes. A brief introduction of principle of 2 mm CW Tm Laser is giv-en, analyzing the photothermal modeling of thulium laser-tissue interaction, comparing 2 mm CW Tm Laser with tradi-tional laser.