Research On The Design Theory And Key Technologies Of Large Power Valve-Control Hydrodynamic Coupling

As the link between working machine and driving machine, valve-control hydrodynamic coupling, which using pure water as working medium, is one of the most effective soft-start equipments for large power AFC (Armoured Face Conveyor) in the mining face. Valve-control coupling is suitable for the frequency start with heavy load and has the function of overload protection and speed control, so it has been the leading soft-start equipment for AFC installed more than 800kW capacity motor for single drive. As it is a complicated system which integrates mechanism, electronic, hydraulic and hydrodynamic, so there is no valve-control coupling product in domestic now,and the related studies are also rare. It has been a bottle-neck of the development of large AFC.The working chamber formed by pump wheel and turbine wheel is the core technique of a coupling, and a serial of problems such as structure strength and heat exchange become outstanding with the increasing of power. Aiming at the soft starting of AFC behind supports(2×1000kW) and focusing on the key technologies,research work such as flow field analysis of working chamber, laws of liquid distribution, structural mechanics of working pump and develop of control valve block were done. The main research work of this dissertation includes:According to the resistance calculation formula and the working mode of AFC behind supports, it was pointed out that the wildly load varying even overload were the main features influenced by the coal drop. Then the parameters matching relationships among coupling, electric motor and AFC were established. In order to get the perfect"long wall characteristic curve", the peach shaped chamber were chosen as the original chamber to be further analyzed after comparing the existing loop circles.The 3-D flow field calculation method was established by analyzing the basic CFD models. The full-filled steady flow field of standard peach shaped chamber was simulated using realizable k-εturbulence model and polyhedron meshes. The difference between predicated torque coefficient and the one from literature was very small,so the validity of calculation model was verified according to similarity theory. The simulation result shows that the overload coefficient is too large to satisfy the demand of AFC, then the working chamber was adjusted from thickness and blade shapes, retainer height, and the new chambers were analyzed by CFD again. Predicated torques show that the structure"height low internal blades+retainer"has high efficient and can satisfy the torque limiting demand.The quasi-transient flow of air-water two phase flow in the optimized charmer was studied utilizing VOF model. The liquid distribution comparisons between simulation and test results from GAMMA tomography method and array sensor method proved that the VOF model was suitable for tracking the moving interface between air and water. The distribution and flow laws were further studied and the torques of different filled rates were predicated, which can be taken as the theoretical reference for speed regulation.One-way FSI method was introduced and the structure mechanics was analyzed using CFD and FEA softwares. The pump wheel at the driving end of a dual-chamber bears the harshest loading condition, so the strength of which was analyzed using CFD result, and the weak places were strengthened. While improving calculation accuracy of strength,new phenomenon which cannot appear in common FEA was found by FSI analyzing that the blades bear alternating load, so fatigue failure is easier to happen. The static frequency and dynamic frequency at different loads were got by modal analysis based on FSI, and more overall dynamic characteristics of the pump wheel were mastered.The pilot operated solenoid valve block was designed following the half-opened circuit, and the performance demand of which was low pressure, large flow and owing anti-blocking ability. The serial hydraulic resistances model of the pilot operated valve was built, according to which the pressure and structure conditions were obtained. In order to simulate the relationship between nozzle and piloted valve, the water pressure test platform was built and the characteristics of different nozzles were tested on it. The influences of spring and nozzle on the static and dynamic characteristics were investigated by AMESim software and the optimized parameters of valve block were established.The opening pressure, pressure at steady flow, response time and pressure varying at the cycle inlet of solenoid valve block were tested on an simple test system. Then the combined experiment of valve block and the coupling were carried on the 2000kW test stand. The torque coefficients of full-filled were obtained which meet well with CFD simulate one and conform to the"long wall characteristic curve". The good consistency between simulation and testing results provides a very important tool for the modern design of valve-control coupling.At last, The valve-control coupling was developed taking key technologies such as chamber type, wheel structure and control valve block main line, using CFD,FSI and AMESim ect. aided approach and it can ensure the soft-start of a large power AFC. The modern design theory and method of valve-control coupling is preliminary established which can improve the quality it and reduce the R & D period and cost.There are 122 figures, 16 tables and 160 references in the dissertation.