Electrohydrodynamics Laboratory Control of Liquid and LiquidVapor Flow

Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- - Control of Liquid and Liquid/Vapor Flow Distributions With EHD Conduction Pumping Y. Feng and J. Yagoobi Heat Transfer Enhancement and Two-Phase Flow Laboratory Mechanical, Materials, and Aerospace Engr. Dept. Illinois Institute of Technology Chicago, USA

Motivation Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- - n thermal management of parallel evaporators and condensers n correct liquid distribution required among parallel lines n local hot areas and dry-outs due to maldistribution n EHD pumping as an active control method n conduction pumping, a right choice

EHD Conduction Pump Electrode Design Schematic Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Electrode Picture Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Working Fluid, R-123 + +++ + ++ Electrohydrodynamics Laboratory e/e 0 se K (S/m) (m 2/V. s) 4. 8 2. 7 E-8 4. 8 E-8 m r (Pa. s) (kg/m 3) hfg (k. J/kg) 417. 6 E-6 1464 171. 4 -- - - - -- -

Pressure Generation in the Absence of a Net Flow Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

EHD Conduction Pump with Three Electrode Pairs Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Flow Distribution Control Apparatus Utilizing EHD Conduction Pump Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- - Experimental Results – Liquid Phase (mass flux = 100 kg/m 2 s, T = 25 C)

Flow Distribution, e = 10 k. V Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Current Consumption, e = 10 k. V Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Flow Distribution, e = 15 k. V Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Current Consumption, e = 15 k. V Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- - Experimental Results – Liquid/Vapor Phases (mass flux = 50 kg/m 2 s, Tsat = 25 C)

Pressure Drop Along EHD Conduction Pump and Branch Tube, Vapor Quality = 6% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Pressure Drop Along the Other Branch Tube, Vapor Quality = 6% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Pressure Drop Along EHD Conduction Pump and Branch Tube, Vapor Quality = 20% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Pressure Drop Along the Other Branch Tube, Vapor Quality = 20% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Pressure Drop Along EHD Conduction Pump and Branch Tube, Vapor Quality = 26% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Pressure Drop Along the Other Branch Tube, Vapor Quality = 26% Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- -

Conclusions Electrohydrodynamics Laboratory + +++ + ++ -- - - - -- - Electrically driven flow generated by the EHD conduction pump successfully controlled the flow distribution between two parallel branch lines.

Acknowledgement Electrohydrodynamics Laboratory + +++ + ++ American Society of Heating, Refrigerating and Air Conditioning Engineers. -- - - - -- -