Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/6687
Title: Compound effect of EHD and surface roughness in pool boiling and CHF with R-123
Authors: Ahmad, SW
Karayiannis, TG
Kenning, DBR
Luke, A
Keywords: Pool boiling;Surface roughness;Critical heat flux;Electrohydrodynamic enhancement
Issue Date: 2011
Publisher: Elsevier
Citation: Applied Thermal Engineering, 31(11-12): 1994 - 2003, Aug 2011
Abstract: Saturated pool boiling of R-123 at 1 bar, including the critical heat flux (CHF), was enhanced by modifying the surface characteristics and applying a high intensity electrostatic field, the latter termed electrohydrodynamic (and abbreviated EHD) enhancement. The heat flux was varied from very low values in the natural convection regime up to CHF. Experiments were performed with increasing and decreasing heat flux to study boiling hysteresis without and with EHD. Boiling occurred on the sand blasted surface of a cylindrical copper block with embedded electrical heating elements, with standardized surface parameter Pa = 3.5 µm. The electric field was generated by a potential of 5 kV to 25 kV, applied through a 40 mm diameter circular electrode of ss-304 wire mesh, aperture size 5.1 mm, located at distances of 5 - 60 mm from the surface, with most of the data obtained for 20 mm. The data for the rough surface were compared with earlier data for a smooth surface and indicated a significant increase in the heat transfer rates. EHD produced a further increase in the heat transfer rates, particularly at low heat flux values and near the CHF. Boiling hysteresis was reduced progressively by EHD and eliminated at high field strength.
Description: Copyright @ 2011 Elsevier
URI: http://www.sciencedirect.com/science/article/pii/S1359431111001372
http://bura.brunel.ac.uk/handle/2438/6687
DOI: http://dx.doi.org/10.1016/j.applthermaleng.2011.03.005
ISSN: 1359-4311
Appears in Collections:Publications
Mechanical and Aerospace Engineering
Dept of Mechanical Aerospace and Civil Engineering Research Papers

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