Electroosmotic pump
Encyclopedia
An electroosmotic pump or EO pump, is used for generating flow or pressure by use of an electric field. One application of this is removing liquid flooding water
from channels and gas diffusion
layers and direct hydration
of the proton exchange membrane
in the membrane electrode assembly
(MEA) of the proton exchange membrane fuel cell
s.
nanospheres or hydrophilic porous glass
, the pump
ing mechanism is generated by an external electric field
applied on an electric double layer (EDL), generates high pressures (more than 340 atm
(34 MPa) at 12 kV applied potentials) and high flow rates (e.g., 40 ml
/min at 100 V
in a pumping structure less than 1 cm³ in volume). EO pumps are compact, have no moving parts, and scale favorably with fuel cell design. The EO pump might drop the parasitic load of water management in fuel cells from 20% to 0.5% of the fuel cell power.
s.
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
from channels and gas diffusion
Diffusion
Molecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
layers and direct hydration
Hydration
Hydration may refer to:* Hydration reaction, a chemical addition reaction where a hydroxyl group and proton are added to a compound* Mineral hydration, an inorganic chemical reaction where water is added to the crystal structure of a mineral...
of the proton exchange membrane
Proton exchange membrane
A proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...
in the membrane electrode assembly
Membrane electrode assembly
A membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:...
(MEA) of the proton exchange membrane fuel cell
Proton exchange membrane fuel cell
Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
s.
Principle
Electroosmotic pumps are fabricated from silicaSilicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
nanospheres or hydrophilic porous glass
Porous glass
Porous glass is glass that includes pores, usually in the nm- or µm-range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses , followed by liquid extraction of one of the formed phases; through the sol-gel process; or simply by...
, the pump
Pump
A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...
ing mechanism is generated by an external electric field
Electric field
In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...
applied on an electric double layer (EDL), generates high pressures (more than 340 atm
Atmosphere (unit)
The standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of pressure. For practical purposes it has been replaced by the bar which is 105 Pa...
(34 MPa) at 12 kV applied potentials) and high flow rates (e.g., 40 ml
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
/min at 100 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
in a pumping structure less than 1 cm³ in volume). EO pumps are compact, have no moving parts, and scale favorably with fuel cell design. The EO pump might drop the parasitic load of water management in fuel cells from 20% to 0.5% of the fuel cell power.
Cascaded electroosmotic pumps
High pressures or high flow rates are obtained by positioning several regular electroosmotic pumps in series or parallel respectively.Planar shallow electroosmotic pump
Planar shallow electroosmotic pumps are made of parallel shallow microchannelMicrochannel
Microchannel can refer to* Basic structure used in microtechnology, see Microchannel .* Micro Channel architecture in computing...
s.
See also
- Electroosmotic flow
- Capillary electrophoresisCapillary electrophoresisCapillary electrophoresis , also known as capillary zone electrophoresis , can be used to separate ionic species by their charge and frictional forces and hydrodynamic radius. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the influence of an...
- MicrofluidicsMicrofluidicsMicrofluidics deals with the behavior, precise control and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter, scale.Typically, micro means one of the following features:* small volumes...
- MicropumpMicropumpAlthough any kind of small pump is often referred to as micropump, a more accurate and up-to-date definition restricts this term to pumps with functional dimensions in the micrometre range. Such pumps are of special interest in microfluidic research, and have become available for industrial product...
- Sol-gel
- Glossary of fuel cell termsGlossary of fuel cell termsThe Glossary of fuel cell terms lists the definitions of many terms used within the fuel cell industry. The terms in this fuel cell glossary may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but a few. –...