Designing a micro-electro-mechanical system (MEMS) that operates on too small a scale to measure The preconcentrator needs to collect as much analyte as possible and release most or all of it in a very short period of time
Sandia Corporation, a Lockheed Martin Company, has developed a hand-held chemical analysis system designed to be used by first responders for the detection of toxic agents. The first stage of the ChemLab system is the preconcentrator which samples and collects analytes from an inlet gas stream and ejects them on command into the separation stage. Due to difficulties associated with measuring flow on a micro scale, designing the preconcentrator was challenging. Sandia engineers worked with consultants at ESI Group to simulate fluid flow and chemical reactions through the preconcentrator with ESI’s CFD-ACE+ computational fluid dynamics (CFD) software. The simulation results showed that in the initial concept design flow rushes along the sides of the preconcentrator with poor wetting of the adsorbent pillars resulting in inefficient adsorption of analyte. Sandia and ESI engineers modified the design by rearranging the pillars to improve wetting and optimize the adsorption and desorption phases.
Sandia substantially improved the preconcentrator design Simulation reduces the number of prototypes that were needed.