Nozzle Design and Experimental Study of Abrasive Water Jets Bit

A new type of bits called abrasive water jets bit can solve the problem that the speed is slow in hard rock drilling.The analysis of working principle for abrasive water jets bits shows that the efficiency of breaking rock by abrasive water jets bit is limited by punching speed affected by the structure of nozzle.The main parameters of affecting punching speed were studied by uniform design and numerical simulation.The optimum structure parameters of nozzle and experimental parameters were determined.There are interactions between pressure,abrasive concentration with structures of nozzle.Laboratory experiments show that the drilling speed by optimized abrasive water jets bit is 1.57 times faster than original three wings bit,1.25 times larger than control group 1 and 1.18 times than control group 2,which shows significant advantages in hard rock drilling.