The good reverse circulation effect is the key to the reverse circulation drilling of the hollow-through DTH (Down-the-hole) hammer. For this reason, our research group has developed and designed two kinds of new type of reverse circulation bits. Hydrodynamic software is used to comparatively analyze the flow fields of the two kinds of bits. The simulation experiment shows that the slit-type inner nozzle structure has better pumping effect and the speed cloud chart shows that the wall effect of the slit structure is the best, and its flow field is evenly distributed, which greatly reduces the interference effect of the fluid. In Yuanjia Village Iron Mine in Lanxian County of Taiyuan Iron and Steel Group, a field test is conducted on the slit-type inner nozzle reverse circulation bit, indicating an accumulative footage of 43.2m, and drilling efficiency of 12.8m/h or more per hour. The field test shows that the newly developed slit-type reverse circulation bit has good reverse circulation effect, and realizes the highly efficient and fast drilling of hollow-through DTH hammer reverse circulation bit, which has greatly improved utilization performance
reverse circulation bit, hollow-through dth hammer reverse circulation bit, slit-type inner nozzle structure, the double-row inner nozzle structure
Bo K., Yin K., Peng J. M. (2011). Reverse circulation DTH hammer drilling technique. Global Geology, Vol. 14, No. 4, pp. 259-264. https://doi.org/10.3969/j.issn.1673-9736.2011.04.08
Bonnington S. T., King A. L. (1976). Jet pumps and ejectors: A state of the art review and bibliography (2nd edition), British Hydromechanics Research Association Fluid Engineering. Cranfield, Bedford, UK.
Bu C. G., Qu Y. G., Cheng Z. Q., Liu B. L. (2009). Numerical simulation of impact on pneumatic DTH hammer percussive drilling. Journal of Earth Science, Vol. 20, No. 5, pp. 868-878. https://doi.org/10.1007/s12583-009-0073-5
Causon D. M., Ingra D. M., Mingham C. G. (2000). Calculation of shallow water flows using a Cartesian cut cell approach. Advances in Water Resources, Vol. 23, No. 5, pp. 545-562. https://doi.org/10.1016/S0309-1708(99)00036-6
Chiang L. E., Elias D. A. (2000). Modeling impact in down-the-hole rock drilling. International Journal of Rock Mechanics and Mining Sciences, Vol. 37, pp. 599-613. https://doi.org/10.1016/S1365-1609(99)00124-0
Geng R. L. (1995). Air drilling with multiple-technique. Geological Publishing House, Beijing, China.
Hao S. Q., Yin K., Huang H. W. (2008). Improvement and optimized design on the structure of pneumatic down-the-hole hammer reverse circulation drilling bit. Exploration Engineering (Rock & Soil Drilling and Tunneling), Vol. 10, pp. 18-22. https://doi.org/10.1021/jf1012506
Hartmann D., Meinke M., Schr D. W. (2011). A strictly conservative Cartesian cut-cell method for compressible viscous flows on adaptive grids. Computer Methods in Applied Mechanics and Engineering, Vol. 200, No. 9-12, pp. 1038-1052. https://doi.org/10.1016/j.cma.2010.05.015
Ingram D. M., Causon D. M., Mingham C. G. (2003). Developments in Cartesian cut cell methods. Mathematics and Computers in Simulation, Vol. 61, No. 3-6, pp. 561-572. https://doi.org/10.1016/s0378-4754(02)00107-6
Keenan J. H., Neumann E. P. (1950). An investigation of ejector design by analysis and experiment. Journal of Applied Mechanics, Vol. 72, pp. 299-309.
Tucker P. G., Pan Z. A. (2000). Cartesian cut cell method for incompressible viscous flow. Applied Mathematical Modelling, Vol. 24, No. 8-9, pp. 591-606. https://doi.org/10.1016/S0307-904X(00)00005-6
Wang M. S., Yin, K., Chen, B. Y., Jia, L. (2005). Application of hollow-through DTH to completed strata and improvement of reverse. Circulation Drilling Bit, Vol. 33, No. 5. Retrieved from https://doi.org/10.1016/j.taap.2011.05.013
Yin K., Wang, M. S., Peng J.M., and Wang R. S. (2010). Percussive-rotary drilling. Geological Publishing House, Beijing, China.
Zhang Z. P., Yin K., Jiang R. Q., Sun Y. H. (2007). The new technology of rock and soil drilling engineering. Geological Publishing House, Beijing, China.
Zhu L. H., Yin K., Wang R. H., Liu J. L., Ren H. (2012). Angle research on inner orifice for suction type reverse circulation drill bit. Construction Machinery and Equipment, Vol. 43, No. 1, pp. 23-27