AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
An Aerosol Gas Exchange System (AGES) for Engine Exhaust Conditioning
MARKUS BAINSCHAB, Sampsa Martikainen, Panu Karjalainen, Jorma Keskinen, Alexander Bergmann, Graz University of Technology
Abstract Number: 429 Working Group: Instrumentation and Methods
Abstract The current European Particle Number (PN) emission standard regulates the emission of non-volatile particles larger than 23 nm in diameter. In order to assess this quantity correctly, a sampling system has to remove condensable semivolatile compounds and inhibit growth of sub-cut size particles. State-of-the-art technologies tackle this task by diluting the sampled exhaust with hot air and subsequently providing residence time to the sample for evaporation (evaporation tube), oxidation (catalytic stripper) or adsorption (thermal denuder) of volatile compounds.
We present an Aerosol Gas Exchange System (AGES), which can be used as an alternative to for engine exhaust conditioning for particle number measurements. The system’s core element is a counter flow denuder, which has previously been shown to provide effective removal of gaseous species from an aerosol while exhibiting limited particle losses. Diffusional transport through a porous membrane allows the exchange of gaseous compounds in the aerosol with a freely selectable purge gas. By integrating this device into a system comprising heaters, temperature measurement, flow control and pressure regulation, we provide an aerosol conditioning system that is applicable for a variety of sources at changing pressure and temperature conditions.
We performed laboratory-based experiments to test the AGES’ capabilities in removing a variety of gaseous species that are abundant in engine exhaust. We altered the sample temperature and the flow rate to evaluate the impact of these parameters on the exchange performance of the system and fractional particle penetration. Additionally, we provide a detailed mathematical model and multiphysical simulations, which enable the prediction of the exchange efficiencies of untested substances.
The presented results demonstrate the potential of the AGES for engine exhaust conditioning amongst many other possible applications like atmospheric studies and aerosol mass spectrometry.