The efficiency of electrokinetic pumping at a condition of maximum.

Journal Article · Sun Aug 01 04:00:00 EDT 2004 · Proposed for publication in Electrophoresis.

OSTI ID:951727

Griffiths, Stewart K; Nilson, Robert H

Numerical methods are employed to examine the work, electric power input, and efficiency of electrokinetic pumps at a condition corresponding to maximum pump work. These analyses employ the full Poisson-Boltzmann equations and account for both convective and conductive electric currents, including surface conductance. We find that efficiencies at this condition of maximum work depend on three dimensionless parameters, the normalized zeta potential, normalized Debye layer thickness, and a fluid property termed the Levine number indicating the nominal ratio of convective to conductive electric currents. Efficiencies at maximum work exhibit a maximum for an optimum Debye layer thickness when the zeta potential and Levine number are fixed. This maximum efficiency increases with the square of the zeta potential when the zeta potential is small, but reaches a plateau as the zeta potential becomes large. The maximum efficiency in this latter regime is thus independent of the zeta potential and depends only on the Levine number. Simple analytical expressions describing this maximum efficiency in terms of the Levine number are provided. Geometries of a circular tube and planar channel are examined.

• Research Organization: Sandia National Laboratories
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 951727
• Report Number(s): SAND2004-4373J
• Journal Information: Proposed for publication in Electrophoresis., Journal Name: Proposed for publication in Electrophoresis.
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
COMPUTERIZED SIMULATION
EFFICIENCY
ELECTRIC CURRENTS
ELECTRODYNAMICS
ELECTROPHORESIS
PUMPING
SURFACE POTENTIAL