Investigation of soot oxidation by coupling LII, SAXS and scattering measurements

Abstract

International audienc

Chemical discrimination of the particulate and gas phases of miniCAST exhausts using a two-filter collection method

“…The minimum collection efficiency, which is also referred to as the most penetrating particle size (MPPS), is obtained for the 100-300 nm size range. However, some studies showed that the MPPSs for QFF may peak around 60 nm and are possibly < 100 nm for other fibrous media (Brochot et al, 2019;Zíková et al, 2015). While these measured values are mostly influenced by both the flow velocity in the sampling line and the pressure drop at the surface of the filter, our flow conditions are close to those used in the work of Zíková et al (2015).…”

“…PM was sampled from the exhaust of a miniCAST generator (5201c) from Jing Ltd., as described previously in Yon et al (2018), for example. Briefly, the miniCAST contains a propane-nitrogen flame with operating conditions controlled by the flow rates of propane, nitrogen, oxidation air (Q air ), and dilution air.…”

“…These QFFs are typically used in soot collection, for example in studies of aircraft PM (Delhaye et al, 2017), and are also employed when deriving organic carbon to total carbon ratios (OC/TC) of deposited soot (Bescond et al, 2016;Yon et al, 2015). QFFs are chosen because they proved to be highly efficient in capturing combustion emissions and they have a stable penetration curve among other filters when a range of physical parameters are varying in the sampling line (Zíková et al, 2015). From a theoretical point of view, it is very difficult to predict the collection efficiency of QFF for particles within the nanometer size domain, as generated in our combustion conditions (e.g., 99-166 nm modal diameter; Bescond et al, 2016).…”

“…From a theoretical point of view, it is very difficult to predict the collection efficiency of QFF for particles within the nanometer size domain, as generated in our combustion conditions (e.g., 99-166 nm modal diameter; Bescond et al, 2016). Filter collection efficiency is directly related to inertial impaction, direct interception, Brownian diffusion, and electrostatic forces (Brochot et al, 2019;Lindsley, 2016;Zíková et al, 2015). The resulting component of these forces is translated into a function that displays near-100 % collection efficiency for particles smaller than 20 nm and larger than 300 nm.…”

Caracterização Experimental Da Distribuição Da Fuligem Nas Proximidades De Um Queimador Tipo Bluff-Body

“…Diferentes tipos de chamas de difusão laminares foram empregadas na análise de formação de fuligem. Em estudos feitos por (20) foi empregada a técnica de incandescência, LII, no estudo da oxidação de partículas de fuligem em uma chama laminar pré-misturada, usando uma mistura de propano/ar, num queimador do tipo McKenna. Os resultados mostraram que o diâmetro das partículas primárias de fuligem não varia significativamente durante o pulso laser.…”