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Heat Pipe Science and Technology, An International Journal

ISSN Печать: 2151-7975
ISSN Онлайн: 2151-7991

Archives: Volume 1, 2010 to Volume 8, 2017

Heat Pipe Science and Technology, An International Journal

DOI: 10.1615/HeatPipeScieTech.2013006512
pages 187-201

EVAPORATION FROM MICROPOROUS SURFACES IN A MECHANICALLY PUMPED TWO-PHASE LOOP

Matthias Winter
Institute for Technical Thermodynamics, Center of Smart Interfaces, Technische Universitat Darmstadt, Petersenstrasse 17, 64287 Darmstadt, Germany
Peter Stephan
Institute for Technical Thermodynamics, Technische Universität Darmstadt, Alarich-Weiss-Str. 10, 64287 Darmstadt, Germany

Краткое описание

The increasing application of high-power-density electronic components, for example, in space applications or data processing centers, causes the need of heat-transfer devices that can handle the high heat fluxes dissipated by these components. A prototype of a mechanically pumped two-phase loop has been developed at the Institute for Technical Thermodynamics in cooperation with OHB System AG and ESA/ESTEC. The loop incorporates miniature evaporators that can be mounted directly on the heat-dissipating device, minimizing temperature differences between the heat-dissipating part and the cooling device. Three evaporators are arranged in parallel to investigate the performance of the loop during multievaporator operation at different heat loads at the evaporators. In this study the heat-transfer coefficients of the new sintered surface could be increased up to 20 W/(cm2 K). The fouling of the surface slows down due to a higher porosity (bigger grain size, here 60 µm). The critical heat flux of the porous surfaces measured is limited to approx. 90 W/cm2 and does not increase with the volume flux (above 30 mL/min) as it happens with the smooth reference and a new microstructured surface. The microstructured surface reaches a critical heat flux of 152.6 W/cm2 and a heat-transfer coefficient of 6.5 W/(cm2 K) which is the best overall performance of all tested structures inside this evaporator type until now. System tests with three evaporators at different heat loads show stable system behavior. The saturation pressure inside the evaporators depends on the system heat load.

ЛИТЕРАТУРА

  1. Kandlikar, S.G. , Fundamental issues related to flow boiling mini channels and microchannels.

  2. Kim, Y., Choi, C., Lee, K., and Han, D. , Experimental study of spray cooling performance on micro-porous coated surfaces.

  3. Schweizer, N., Stephan, P., and Schlitt, R. , A concept for a miniature, mechanically pumped two-phase cooling loop.

  4. Thome, J.R., Dupont, V., and Jacobi, A.M. , Heat transfer model for evaporation in microchannels, Part I. Presentation of the model.

  5. Winter, M., Schweizer, N., Stephan, P., and Schlitt, R. , Mechanically pumped two-phase loop for space application.


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