Disc pump is widely used in difficult-pump-medium transportation such as petroleum and chemical industry. Discontinuous blade impellers play an important role in the passability and energy efficiency of disk pump. The research of design and internal flow mechanism are particularly important. Based on the structural characteristics and the internal flow mechanism of the original model, the improved design of the blade structure is carried out. Through the experimental verification and the numerical analysis of multiple working conditions, the influence law of the new composite blade on the hydraulic characteristics and internal flow mechanism of the disc pump is obtained. The results show that the error of energy efficiency characteristics of simulation and experiment under different flow conditions is within 5%, and the accuracy of simulation results meets the requirements; The hydraulic characteristics of the improved model are about 5.8% higher than that of the original model. The driving force of the new composite blade is more sufficient and the flow field is improved more obviously; The low pressure is located in the center of the impeller and gradually increases to the outlet of the impeller. There is obvious energy and mass conversion between the bladed region and bladeless region. The research results can provide a reference for the structural design of disc pump composite blade and the analysis of internal flow mechanism.

Automatic slurry mixing device, one of the core equipment of dynamic kill drilling (DKD) system, is the key to determine whether the drilling fluid system can provide precise density for bottom layer in time and effectively, and also the key equipment to control the operation risk of ultra-deep water drilling in the face of narrow pressure window. Based on the incompressible viscous flow characteristics of non-Newtonian fluid mixed with seawater and combined with the actual drilling fluid field situation of offshore drilling platform, a kind of tubular DKD mixer with dumbbell shaped nozzle as jet element is designed in this paper, which is verified by theoretical calculation and numerical simulation. Finally, “Y type reverse reflux (60°) + 90° cross jet element” was determined as the final structural design scheme. At the same time, the influences of inlet flow rate, length of eddy current section and incident Angle on mixing effect of mixer are studied, and a seriation design scheme of dynamic kill drilling (DKD) mixer is proposed, and a seriation design chart of product is completed.