Experimental assessment of a new salt aerosol generator for measuring efficiency of automotive air filters

Abstract

Generation of polydisperse KCl aerosol with a new salt aerosol generator was investigated. Special attention was paid on particles with diameters between 3 and 10 μm. The main improvement consists of the different routes of KCl solution droplets. In traditional generators, the solution droplets travel through one cylinder; while in the case analyzed here, after spray atomization, the droplets travel through two cylinders in series. The first cylinder was fed with warm air and the second one with cold air. In such way, the complete evaporation of the water from the droplets can be ensured. The influencing factors of the generated aerosol size distribution were investigated. The data measured show that the concentration of generated aerosol becomes higher both increasing the flow rate of the KCl solution injected in the first cylinder and increasing the concentration in the solution. The temperature of solution influences mainly the generation of smaller KCl particles (0.3–3 μm). The amount of hot air used in the generation process increases the concentration of larger KCl particles (>3 μm) while cold air does not have the same effect. The aerosol generator is able to generate KCl aerosol stably. This instrument can be used effectively for testing air filters for automotive.

Keywords

aerosol generation / potassium chloride aerosol / droplet-to-particle conversion / air filter testing

References

[1] TronvilleP., RiversR.. International standards: Filters for vehicular applications [J]. Filtration & Separation, 2005, 42(9): 24-27

[2] ISO/TS 19713-1:2010. Road vehicles-inlet air cleaning equipment for internal combustion engines and compressors-Part 1: Fractional efficiency testing with fine particles (0.3 μm to 5 μm optical diameter) [S]. 2010.

[3] BaronP. A., WillekeK.Aerosol measurement: Principles, techniques, and applications, 20052nd EditionNew York, John Wiley & Sons: 936-938

[4] KollarL. E., FarzanehM.. Modeling the evolution of droplet size distribution in two-phase flows [J]. International Journal of Multiphase Flow, 2007, 33(11): 1255-1270

[5] HandscombC. S., KraftM., BaylyA. E.. A new model for the drying of droplets containing suspended solids [J]. Chemical Engineering Science, 2009, 64(2): 628-637

[6] LeongK. H.. Morphology of aerosol particles generated from the evaporation of solution drops [J]. Journal of Aerosol Science, 1981, 12(5): 417-435

[7] OkuyamaK.. Preparation of micro-controlled particles using aerosol process [J]. Journal of Aerosol Science, 1991, 22(S1): S7-S10

[8] EslamianM., AhmedM., AshgrizN.. Modeling of solution droplet evaporation and particle evolution in droplet-to-particle spray methods [J]. Drying Technology: An International Journal, 2009, 27(1): 3-13

[9] MaedaK., ToharaA., AsakumaY., FukuiK.. Formation of fine crystals of potassium chloride dissolved in aqueous ethanol solution by spray evaporation [J]. Chemical Engineering Science, 2009, 48(7): 1270-1273

[10] VehringR., FossW. R., Lechuga-BallesterosD.. Particle formation in spray drying [J]. Journal of Aerosol Science, 2007, 38(7): 728-746

[11] LimE. W. C., KohS. H., LimL. K., OreS., TayB. K., MaY.-f., WangC. H.. Experimental and computational studies of liquid aerosol evaporation [J]. Journal of Aerosol Science, 2008, 39(7): 618-634

[12] GB/T 646-1993. Chemical reagent-potassium chloride [S]. 1993.

[13] YamadaM., FukusakiS., KawanamiT., SawadaI., HoribeA.. Surface tension of aqueous binary solutions [J]. International Journal of Thermophysics, 1997, 18(6): 1483-1493

[14] MastersK.Spray drying handbook, 19854th EditionLondon, George Godwin Limited: 185

[15] ANSI/ASHRAE Standard 52.2-2007. Method of testing general ventilation air-cleaning devices for removal efficiency by particle size [S]. 2007.