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  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Analiza numeryczna skuteczności zastosowania wstecznych otworów w świdrach udarowo-obrotowych
    (2007) Knez, Dariusz; Bednarz, Stanisław
    The percussion-rotary bits used for drilling blast holes in mining is still justifiable from the economical point of view. Cogged-bits are more frequently applied than the cross-blade bits. The drilling rate and footage are to some extent limited by the quality of washing the wellbore bottom. The disturbed process of cuttings removal from the well with air mud in the zone where the bit is connected with the downhole hammer. Attempts at using the reverse holes in the bit body were made. The analytical description of the effect is hindered by the complex shape of the space in which the mud is flowing. Therefore, the use of numerical methods enables detailed description of drilling mud flow in view of the analyzed problem. The paper presents the results of computer simulations in the form of maps of pressure and flow rate in the zone of the bit and downhole hammer.