Heat transfer and bubble formation in pool boiling: Effect of basic surface modifications for heat transfer enhancement

Design and realization of micro structured surfaces for thermodynamic applications

“…A lot of researches have been carried out in the last years to describe the heat transfer phenomena and possibilities to enhance the heat transfer efficiency of heating surfaces (Bergles 1997;Kandlikar 2002;Gorenflo et al 2004;Kotthoff et al 2006;Kim and Kim 2009). Especially for electronic cooling convection and nucleate boiling processes are in focus of interest (Honda and Wei 2003;Honda and Wei 2004;Muzychka 2005;Ndao et al 2009).…”

Preparation, measurement and analysis of the microstructure of evaporator surfaces

“…Some of the heating elements used in literature show a surface structure resulting from the industrial manufacturing processes: drawn wires [16] or tubes [17], rolled tubes with enhanced surfaces [11,18], milled thin plates [19]. Procedures to prepare a uniform structure of various heater geometries with different dimensions have been developed recently to achieve equally distributed potential nucleation sites independent of form and size of the heating element, e.g.…”

“…Different materials, forms and sizes of the heating surfaces are used: copper, CuNi and stainless steel tubes (D = 15 mm [3,4], D = 24.0-25.4 mm [5,6]), copper plates (15 × 200 mm [7]), and tubes coated galvanically by gold [8], and plates sputtered with layers of different material [9]. Macro cavities have been prepared by a rolling process similar to the industrial processes [10,11]. Changes of the surface microstructure by fouling or destruction effects can be correlated with changes of the boiling processes [10,12,13].…”

Circumferential temperature distribution during nucleate pool boiling outside smooth and modified horizontal tubes

“…The difference between the maximum and the minimum temperature value in circumference was about 4 K. Bier et al [3] have conducted research on refrigerant R11. The maximum temperature difference was about 0.07 K. Gorenflo and co-workers [4][5][6][7][8] carried out a systematic study regarding bubble formation on tubes with defined roughness or on surfaces modified by macrostructures for enhancement of heat transfer. Experiments with different organic fluids were performed in order to obtain results over wide range of reduced pressure.…”