Rebound characteristics for 50-mum particles impacting a powdery deposit

M.C. Beek, van, C.C.M. Rindt, J.G. Wijers, A.A. Steenhoven, van

    Research output: Contribution to journalArticleAcademicpeer-review

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    Abstract

    The formation of powdery deposits on the tubes in a waste heat boiler reduces the heat transfer coefficient by about 25%. Because of these fouling layers, the efficiency with which energy can be recovered from flue gases is reduced. The growth of the layers by the deposition of fly ash particles onto the tubes is strongly dependent on the interaction of the incident particle with the bed of particles. In this study the interaction is modelled as the outcome of a 2-body collision between an incident fly-ash particle and a second particle that represents a developing fouling layer. The mass of this second particle is dependent on the characteristics of the layer. The present paper focuses on the applicability of the 2-body collision model to predict the rebound characteristics of 50-ƒÝm particles impacting a powdery deposit. This is studied by impaction experiments of glass particles on different types of glass layers (powdery vs. glued), under various impaction angles (ranging from 00 to 300) and with different incident velocities (ranging from 0.5 m/s to 1 m/s). The experiments are carried out in a vacuumed column and, using a digital camera system, individual impacts are recorded. With this set-up the normal coefficient of restitution, the Coulomb friction coefficient and the proportionality factor are determined for particles in the 50-micrometer range. Besides, a 2-body collision model is developed to simulate the rebound characteristics. From a comparison between the experimental results and the model, it is shown that the 2-body approach to model the rebound characteristics of particles impacting a powdery layer is valid and that the proportionality factor is dependent on the binding between the particles in the layer and the relative particle size of the particles in the layer compared to the size of the incident particles.
    Original languageEnglish
    Pages (from-to)53-64
    JournalPowder Technology
    Volume165
    Issue number2
    DOIs
    Publication statusPublished - 2006

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    Deposits
    Coal Ash
    Fouling
    Fly ash
    Glass
    Waste heat
    Digital cameras
    Flue gases
    Heat transfer coefficients
    Boilers
    Experiments
    Particle size
    Friction

    Cite this

    @article{f4064800171a4b2d9ec0ec2f6b99d687,
    title = "Rebound characteristics for 50-mum particles impacting a powdery deposit",
    abstract = "The formation of powdery deposits on the tubes in a waste heat boiler reduces the heat transfer coefficient by about 25{\%}. Because of these fouling layers, the efficiency with which energy can be recovered from flue gases is reduced. The growth of the layers by the deposition of fly ash particles onto the tubes is strongly dependent on the interaction of the incident particle with the bed of particles. In this study the interaction is modelled as the outcome of a 2-body collision between an incident fly-ash particle and a second particle that represents a developing fouling layer. The mass of this second particle is dependent on the characteristics of the layer. The present paper focuses on the applicability of the 2-body collision model to predict the rebound characteristics of 50-ƒ{\'Y}m particles impacting a powdery deposit. This is studied by impaction experiments of glass particles on different types of glass layers (powdery vs. glued), under various impaction angles (ranging from 00 to 300) and with different incident velocities (ranging from 0.5 m/s to 1 m/s). The experiments are carried out in a vacuumed column and, using a digital camera system, individual impacts are recorded. With this set-up the normal coefficient of restitution, the Coulomb friction coefficient and the proportionality factor are determined for particles in the 50-micrometer range. Besides, a 2-body collision model is developed to simulate the rebound characteristics. From a comparison between the experimental results and the model, it is shown that the 2-body approach to model the rebound characteristics of particles impacting a powdery layer is valid and that the proportionality factor is dependent on the binding between the particles in the layer and the relative particle size of the particles in the layer compared to the size of the incident particles.",
    author = "{Beek, van}, M.C. and C.C.M. Rindt and J.G. Wijers and {Steenhoven, van}, A.A.",
    year = "2006",
    doi = "10.1016/j.powtec.2006.03.008",
    language = "English",
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    pages = "53--64",
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    Rebound characteristics for 50-mum particles impacting a powdery deposit. / Beek, van, M.C.; Rindt, C.C.M.; Wijers, J.G.; Steenhoven, van, A.A.

    In: Powder Technology, Vol. 165, No. 2, 2006, p. 53-64.

    Research output: Contribution to journalArticleAcademicpeer-review

    TY - JOUR

    T1 - Rebound characteristics for 50-mum particles impacting a powdery deposit

    AU - Beek, van, M.C.

    AU - Rindt, C.C.M.

    AU - Wijers, J.G.

    AU - Steenhoven, van, A.A.

    PY - 2006

    Y1 - 2006

    N2 - The formation of powdery deposits on the tubes in a waste heat boiler reduces the heat transfer coefficient by about 25%. Because of these fouling layers, the efficiency with which energy can be recovered from flue gases is reduced. The growth of the layers by the deposition of fly ash particles onto the tubes is strongly dependent on the interaction of the incident particle with the bed of particles. In this study the interaction is modelled as the outcome of a 2-body collision between an incident fly-ash particle and a second particle that represents a developing fouling layer. The mass of this second particle is dependent on the characteristics of the layer. The present paper focuses on the applicability of the 2-body collision model to predict the rebound characteristics of 50-ƒÝm particles impacting a powdery deposit. This is studied by impaction experiments of glass particles on different types of glass layers (powdery vs. glued), under various impaction angles (ranging from 00 to 300) and with different incident velocities (ranging from 0.5 m/s to 1 m/s). The experiments are carried out in a vacuumed column and, using a digital camera system, individual impacts are recorded. With this set-up the normal coefficient of restitution, the Coulomb friction coefficient and the proportionality factor are determined for particles in the 50-micrometer range. Besides, a 2-body collision model is developed to simulate the rebound characteristics. From a comparison between the experimental results and the model, it is shown that the 2-body approach to model the rebound characteristics of particles impacting a powdery layer is valid and that the proportionality factor is dependent on the binding between the particles in the layer and the relative particle size of the particles in the layer compared to the size of the incident particles.

    AB - The formation of powdery deposits on the tubes in a waste heat boiler reduces the heat transfer coefficient by about 25%. Because of these fouling layers, the efficiency with which energy can be recovered from flue gases is reduced. The growth of the layers by the deposition of fly ash particles onto the tubes is strongly dependent on the interaction of the incident particle with the bed of particles. In this study the interaction is modelled as the outcome of a 2-body collision between an incident fly-ash particle and a second particle that represents a developing fouling layer. The mass of this second particle is dependent on the characteristics of the layer. The present paper focuses on the applicability of the 2-body collision model to predict the rebound characteristics of 50-ƒÝm particles impacting a powdery deposit. This is studied by impaction experiments of glass particles on different types of glass layers (powdery vs. glued), under various impaction angles (ranging from 00 to 300) and with different incident velocities (ranging from 0.5 m/s to 1 m/s). The experiments are carried out in a vacuumed column and, using a digital camera system, individual impacts are recorded. With this set-up the normal coefficient of restitution, the Coulomb friction coefficient and the proportionality factor are determined for particles in the 50-micrometer range. Besides, a 2-body collision model is developed to simulate the rebound characteristics. From a comparison between the experimental results and the model, it is shown that the 2-body approach to model the rebound characteristics of particles impacting a powdery layer is valid and that the proportionality factor is dependent on the binding between the particles in the layer and the relative particle size of the particles in the layer compared to the size of the incident particles.

    U2 - 10.1016/j.powtec.2006.03.008

    DO - 10.1016/j.powtec.2006.03.008

    M3 - Article

    VL - 165

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    EP - 64

    JO - Powder Technology

    JF - Powder Technology

    SN - 0032-5910

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    ER -