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Improved theoretical modeling of a cyclone separator as a diesel soot particulate emission arrester

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Abstract

Particulate matter is considered to be the most harmful pollutant emitted into air from diesel engine exhaust, and its reduction is one of the most challenging problems in modern society. Several after-treatment retrofit programs have been proposed to control such emission, but to date, they suffer from high engineering complexity, high cost, thermal cracking, and increased back pressure, which in turn deteriorates diesel engine combustion performance. This paper proposes a solution for controlling diesel soot particulate emissions by an improved theoretical model for calculating the overall collection efficiency of a cyclone. The model considers the combined effect of collection efficiencies of both outer and inner vortices by introducing a particle distribution function to account for the non-uniform distribution of soot particles across the turbulent vortex section and by including the Cunningham correction factor for molecular slip of the particles. The cut size diameter model has also been modified and proposed by introducing the Cunningham correction factor for molecular slip of the separated soot particles under investigation. The results show good agreements with the existing theoretical and experimental studies of cyclones and diesel particulate filter flow characteristics of other applications.

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Abbreviations

A :

inlet cross sectional area of cyclone flow [m2]

H :

inlet height of the cyclone [m]

B :

inlet width of the cyclone [m]

D 1 :

outer diameter of the cyclone [m]

D 2 :

diameter of the vortex finder [m]

D d :

diameter of the dust exit [m]

D p50 :

cut size diameter of the particle [µm]

D p50m :

modified cut size diameter of the particle [µm]

d p :

diameter of soot particle [µm]

F C :

centrifugal force [N]

F D :

drag force acting on the particle [N]

L 1 :

length of the cylindrical portion of the cyclone [m]

L 2 :

length of the conical portion of the cyclone [m]

L i :

inner vortex length [m]

L o :

outer vortex length [m]

V θ :

tangential velocity of the exhaust gas and particle [m]

\( V_{\theta _2 } \) :

tangential velocity of the gas at outer vortex [m/sec]

\( V_{r_2 } \) :

radial velocity of the particles at outer vortex [m/sec]

n :

vortex exponent

T :

exhaust gas temperature in K

N θ :

number of particles remain in the outer vortex at an angle of turn θ

N 0 :

number of particles at the inlet of cyclone, at θ=0

P ref :

reference pressure [pa]

ΔP :

pressure drop across cyclone [pa]

Q :

volume flow rate [m3/sec]

r 1 :

vortex finder or Inner radius of cyclone flow [m]

r 2 :

outer radius of cyclone flow [m]

t :

temperature of the exhaust gas [°C]

ρ c :

density of the exhaust gas [kg/m3]

ρ p :

density of the particle [kg/ m3]

η o :

collection efficiency of outer vortex

η i :

collection efficiency of inner vortex

η overall :

overall collection efficiency of the cyclone

μ :

dynamic viscosity of the gas [kg/m-sec]

θ :

angle of turn in traversing the cyclone [rad]

θ i :

angle of turn of the inner vortex [rad]

θ o :

angle of turn of the outer vortex [rad]

R gas :

characteristic gas constant of the exhaust gas [N-m/kg/°k]

R u :

universal gas constant, in N-m/kmolk

C p :

concentration of the particles per unit area

C p (r1,θ):

concentration of particles at inner radius r 1 & at an angular position θ

C p (r2,θ):

concentration of particles at outer radius r 2 & at an angular position θ

\( \overline {C_p (\theta )_0 } \) :

mean value of particle concentration at outer vortex

\( \overline {C_p (\theta )_i } \) :

mean value of particle concentration at inner vortex

C*:

cunningham correction factor

λ :

mean free path of the gas molecules [µm]

\( \bar u \) :

mean molecular velocity

M :

molecular weight [kg/kmol]

m :

mass of the soot particles

T in :

inlet temperature [K]

References

  • Alexander, R. M. (1949). Fundamentals of cyclone design and operation. Proc. Aust. Inst. Min. Metall., 152/3, 202–228.

    Google Scholar 

  • Bloom, R. (1995). The development of fiber wound diesel particulate filter cartridges. SAE Paper No. 950152, 373–382.

  • Bohnet, M. (1995). Influence of the gas temperature on the separation efficiency of aero-cyclones. Chemical Engineering and Precessing, 34, 151–156.

    Article  Google Scholar 

  • Caplan, K. J. (1968). Source Control by Centrifugal Force and Gravity. A. C. Stern, Edn., Air Pollution, 3, Academic Press. New York. 366–377.

    Google Scholar 

  • Crane, R. I. and Wisby, P. (2000). Light-duty diesel exhaust after-treatment by a multicyclone particulate separator with an oxidation catalyst. Proc. Instn. Mech. Engrs., ProQuest Science J. 214,7, 741.

    Article  Google Scholar 

  • Crawford, M. (1976). Air Pollution Control Theory. McGraw Hill. New York. 259–286.

    Google Scholar 

  • Cortes, C. and Gil, A. (2007). Modeling the gas and particle flow inside cyclone separators. Progress in Energy and Combustion Science.

  • Cutler, W. A. and Merkel, G. A. (2000). A new high temperature ceramic material for diesel particulate filter applications. SAE Paper No. 2000-01-2844, 2508–2518.

  • Davis, M. L. and Cornwell, D. A. (1998). Introduction to Environmental Engineering. McGraw Hill. Singapore. 527–528.

    Google Scholar 

  • Dementhon, J. B. and Martin, B. (1997). Influence of various traps on particulate size distribution. SAE Paper No. 972999, 1604–1622.

  • Dietz, P. W. (1981). Collection efficiency of cyclone separators. AIChE J. 27,6, 888.

    Article  Google Scholar 

  • First, M. W. (1950). Fundamental Factors in the Design of Cyclone Dust Collectors. Ph.D. Dissertation. Harvard University. Cambridge. MA.

    Google Scholar 

  • Horiuchi, M., Saito, K. and Ichihara, S. (1990). The effects of flow — through type oxidation catalysts on the particulate reduction of 1990’s diesel engines. SAE Paper No. 900600, 1268–1278.

  • Kittelson, D. B. (1998). Engines and Nano-particles, A Review. J. Aerosol Sci. 29,5/6, 575–588.

    Article  Google Scholar 

  • Lapple, C. E. (1951). Processes use many collection types. Chemical Engineer 58,5, 144–151.

    Google Scholar 

  • Leith, D. and Metha, D. (1973). Cyclone performance and design. Atmospheric Environment, 7, 527–549.

    Article  Google Scholar 

  • Leith, D. and Licht, W. (1972). The collection efficiency of cylone type particle collectors — A new theoretical approach. AIChE Symp. 68,126, 196.

    Google Scholar 

  • Luders, H., Stommel, P. and Geckler, S. (1999). Diesel exhaust treatment — New approaches to ultra low emission diesel vehicles. SAE Paper No. 1999-01-0108, 18–26.

  • Mayer, A., Egli, H., Burtscher, H., Czerwinski, J. and Gehrig, D. (1995). Particle size distribution downstream traps of different design. SAE Paper No. 950373, 732–742.

  • Mothes, H. and Loffler, F. (1988). Prediction of particle removal in cyclone separators. Int. Chem. Eng. 28,2, 231–240.

    Google Scholar 

  • Mukhopadhya, N., Bose, P. K. and Chakroborty, R. K., (2006). New theoretical approach of designing cyclone separator for controlling diesel soot particulate emission. SAE Paper No. 2006-01-1978.

  • Muntean, G. (1999). A theoretical model for the correlation of smoke number to dry particulate concentration in diesel exhaust. SAE Paper No. 1999-01-0515, 316–322.

  • Khalil, N. and Levendis, Y. A. (1992). Development of a new diesel particulate control system with wall flow filters and reverse cleaning regeneration. SAE Paper No. 920567, 985–999.

  • Oh, S. K., Baik, D. S. and Han, Y. C. (2002). Performance and exhaust gas characteristics on diesel particulate filter trap. Int. J. Automotive Technology 3,3, 111–115.

    Google Scholar 

  • Shepherd, C. B. and Lapple, C. E. (1939). Flow pattern and pressure drop in cyclone dust collectors. Ind. and Eng. Chemistry 31,8, 972–984.

    Article  Google Scholar 

  • Stairmand, C. J. (1951). The design and performance of cyclone separators. Trans. Inst. Chem. Eng., 29, 356.

    Google Scholar 

  • Strauss, W. (1975). Industrial Gas Cleaning. Pergamon Press. 2nd Edn. New York.

  • Suresh, A., Khan, A. and Johnson, J. H. (2000). An experimental and modeling study of cordierite traps — pressure drop and permeability of clean and particulate loaded traps. SAE Paper No. 2000-01-0476, 245–264.

  • Ter Linden, A. J. (1949). Investigations into cyclone dust collectors. Proc. Inst. Mech. Eng., 160, 233–240.

    Article  Google Scholar 

  • Wheeldon, J. L. and Burnard, G. K. (1987). Performance of cyclones in the off-Gas path of a pressurised fluidized bed combustor. Filtration & Separation 24,3, 178–187.

    Google Scholar 

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Bose, P.K., Roy, K., Mukhopadhya, N. et al. Improved theoretical modeling of a cyclone separator as a diesel soot particulate emission arrester. Int.J Automot. Technol. 11, 1–10 (2010). https://doi.org/10.1007/s12239-010-0001-9

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  • DOI: https://doi.org/10.1007/s12239-010-0001-9

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