A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can eas...A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can easily be exfoliated from the surface of the matrix due to weak holding-force with matrix, which made the surface non-smooth. Three Ф36/24 mm laboratorial bits were manufactured to conduct a laboratory drilling test on zirconiacorundum refractory brick. The laboratory drilling test indicates that the abrasive resistance of the bit work layer is proportional to the Si C concentation. The higher the concentration, the weaker the abrasive resistance of matrix. The new impregnated diamond bit was applied to a mining area drilling construction in Jiangxi province, China. Field drilling application indicates that the ROP(rate of penetration) of the new bit is approximately two to three times that of the common bits. Compared with the common bits, the surface of the new bit has typical abrasive wear characteristics,and the metabolic rate of the diamond can be well matched to the wear rate of the matrix.展开更多
This paper reports the numerical simulation of turbulent flow field in rockbits with the k-ε turbulence model and a new twenty-one point scheme for pressure correction equation, which greatly improves the synchronous...This paper reports the numerical simulation of turbulent flow field in rockbits with the k-ε turbulence model and a new twenty-one point scheme for pressure correction equation, which greatly improves the synchronous convergence ane the dependence ofcoupling between velocity and pressure on the pressure relaxation factor. It is numericallyverified that adaptive-manually technique is effective to generate more continuous, smoothand orthogonal Laplace grid system. Numerical results show that there exist vortices andlower pressure domains around the damaged zone, which strengthen the wear by solidparticle in the drilling nuid and induce the cavitation effect, finally causing the erosion anddecrease in the life of rock bit. The damage could be avoided by some modification of theinternal flow structure of rock bit.展开更多
基金Project(51074180)supported by the National Natural Science Foundation of China
文摘A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can easily be exfoliated from the surface of the matrix due to weak holding-force with matrix, which made the surface non-smooth. Three Ф36/24 mm laboratorial bits were manufactured to conduct a laboratory drilling test on zirconiacorundum refractory brick. The laboratory drilling test indicates that the abrasive resistance of the bit work layer is proportional to the Si C concentation. The higher the concentration, the weaker the abrasive resistance of matrix. The new impregnated diamond bit was applied to a mining area drilling construction in Jiangxi province, China. Field drilling application indicates that the ROP(rate of penetration) of the new bit is approximately two to three times that of the common bits. Compared with the common bits, the surface of the new bit has typical abrasive wear characteristics,and the metabolic rate of the diamond can be well matched to the wear rate of the matrix.
文摘This paper reports the numerical simulation of turbulent flow field in rockbits with the k-ε turbulence model and a new twenty-one point scheme for pressure correction equation, which greatly improves the synchronous convergence ane the dependence ofcoupling between velocity and pressure on the pressure relaxation factor. It is numericallyverified that adaptive-manually technique is effective to generate more continuous, smoothand orthogonal Laplace grid system. Numerical results show that there exist vortices andlower pressure domains around the damaged zone, which strengthen the wear by solidparticle in the drilling nuid and induce the cavitation effect, finally causing the erosion anddecrease in the life of rock bit. The damage could be avoided by some modification of theinternal flow structure of rock bit.
