Study of Different Angle Inner Nozzle Flow Field Based on Suction-Type RC Bit

In order to improve the reverse circulation(RC) pumping performance and enhance the effect of RC, the suction-type RC bit on the basis of ejection theory was designed. And with theoretical calculations, computational fluid dynamics(CFD) and experiment, pressure field and velocity field produced by different angle inner nozzles were studied. It was discussed the feasibility of suction principle in enhancing RC effect, and at the same time it was provided a theoretical basis to optimize the design of RC bit. The results show that applying ejectors to improve RC performance is absolutely feasible. Also, the pressure field and velocity field produced by the suction-type RC bit, as the injection angle increases, the pumping capacity both intersection inner nozzle and spiral inner nozzle is decreased, and the spiral inner nozzle´s changes rapidly.