Enhanced Heat Rejection of Microscale Geometries in Convective Flow Boiling Evaporators

13th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications

物理学;能源学

Smith, L. M. Safford^1 ; Connacher, W.J.^1,2 ; Cheng, J.C.^1,3 ; Pisano, A.P.^4

Department of Mechanical Engineering, University of California, Berkeley, 5101 Etchevery Hall, Berkeley, CA, 94720-1774, United States^1

Department of Physics, University of California, Berkeley, United States^2

Department of Electrical Engineering, University of California, Berkeley, United States^3

Department of Engineering, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093-0403, United States^4

关键词: Constant flow rates;    Constant pressures;    Convective flow boiling;    Different pressures;    Limited devices;    Open-loop configuration;    Temperature data;    Wall temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/476/1/012029/pdf
DOI  :  10.1088/1742-6596/476/1/012029

来源: IOP

【 摘 要 】

Four surfaces have been designed, fabricated and tested under convective flow boiling (CFB) conditions in an open loop configuration. They contain features in the 10 micron range and were tested with flow velocities under 3 mm/s. To accomplish these flow rates, this work utilizes a constant pressure potential driving flow, instead of the constant flow rate imposed with a syringe pump. This limited device flooding. The evaporation surfaces were tested to the point of dry-out at three different pressure potentials: 150, 650, and 1150 Pa, across a range of powers from 25 W/cm2to 50 W/cm2. Temperature data was collected from an IR Camera and showed that fluctuations in the wall temperatures exceed 5 °C in more than 50% of the tests and reached differences as high as 23 °C. The wall temperature instabilities in CFB indicate that one temperature may be inaccurate and that by including time as a variable a better understanding of the behaviour at this scale may be revealed.