Fuel Cell Porometer
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Description
The PMI Fuel Cell Porometer provides fully automated through-pore analysis including pore-throat diameter, pore size distribution, mean flow pore diameter, and liquid & gas permeability. The porometer's versatility allows the user to simulate operating conditions. The instrument has special features to measure the effects of compressive stress on a sample, test temperature, sample orientation, and layered structure on pore structure characteristics. The fully automated, user-friendly Fuel Cell Porometer is an asset in quality control and R&D environments.
Principles of Porometry
The flow rate of an inert gas through the dry sample is measured with increasing differential pressure. The sample is brought in contact with a wetting liquid, the liquid spontaneously fills the pores in the sample, and the flow through the wet sample is measured with increasing differential pressure. Pore structure characteristics are computed from measured differential pressure and flow rate.
Where:
- D = Pore Diameter
- γ = surface tension of the wetting liquid
- θ = contact angle of the wetting liquid
- p = differential gas pressure
Applications
The performance of many fuel cell components is determined primarily by the characteristics of the pore structure. Flow of reactants and products is determined by the pore size and pore distribution of electrodes, wide range of gas humidity found in many applications can change the pore structure, components subjected to compressive stress during operation can considerably modify the pore size, pore structure of each layer of multilayer composites often used as fuel cell components can determine the performance of the fuel cell, and reaction rate of reactants is governed by the surface area of through pores. The Fuel Cell Porometer is designed to measure all such relevant pore structure characteristics of fuel cell components.
For more information about the applications please see our other technical papers.
Measurable Pore Structure Characteristics
Measured flow rates through dry and wet samples with increasing differential pressure are used to compute many characteristics.
- Pore throat diameters
- The largest pore throat diameter
- Mean flow pore diameter
- Pore distribution
- Gas permeability
- Through pore surface area (Envelope Surface Area)
Unique Measurable Characteristics
- Characteristics measurable using gas with 0 to 100 % humidity
- Test temperatures can be 200°C and in special situations 800°C
- Pore size measured in samples under compressive stress of up to 1000 psi
- Pore structure of each layer of a multilayer composite
- Pore diameters down to about 0.013 µm
For more information see our Capillary Flow Porometer Brochure, Advanced Capillary Flow Porometer brochure, Porometers Brochure, and Characterization of Pore Structure Brochure.
