Research On Torque Coefficient Of Variable Speed High-power Hydraulic Coupling

Variable speed hydraulic coupling uses the method to achieve the purpose ofregulating the output speed by changing the filling volume of the flow channel underthe same input speed. Variable speed hydraulic coupling has a good energy savingeffect used in speed control of vane fluid machine just as pumps, fans, etc., whichhas the advantages of starting with a light load, overload, slow shock and isolationof torsional vibration.It is widely used similar design method by enlarging or reducing fluidcoupling’s loop diameter for drawing to design hydraulic coupling for series inengineering through the existing hydraulic coupling model. The design which basedon the pump wheel torque coefficient of the actual fluid coupling is equal to the basetype has sufficient accuracy and meets the design requirements when there is nosignificant difference between the two coupling’s diameters or the pump speed. Infact, the pump wheel torque coefficient changes with increase of the diameter orspeed.With the rapid development of machinery industry and the continuousexpansion of equipment capacity, variable speed and high-power products usingmechanical governor has become an inevitable trend. Hydraulic coupling hasconventional small size and low speed and has times of difference with the actualdesign hydraulic coupling.It must be corrected the pump wheel torque coefficientwhen using the similar design that the pump wheel torque coefficient unchanged hasbeen unable to meet the requirements.This article uses the CFD numerical simulation method to research and analysisfor fluid coupling and provides theoretical support for designing high-powerhigh-speed couplings.This article uses UG software for three-dimensional modeling of fluid couplingand it establishs a single blade cyclic symmetry runner model of cyclic symmetry.Itdevides into hexahedral meshes applicated GAMBIT software and simulates thesingle blade cyclic symmetry runner model of cyclic symmetry under the inputspeed of2000r/min. Finally, it has a analysis on the causes of the velocity field andpressure field in the pressure side and the suction side.In this paper, it calculates the torque and moment coefficients in the threepercent of slip of80%filling rate and full-filling under the rated operatingconditions that the input speed of the pump wheel is1000r/min~5000r/min andthe are300mm,400mm,450mm,550mm. Draw variation graphs between the pumpwheel torque coefficient with Loop circle diameters or rotational speed. The results showed that: the change graphs of the pump wheel torque coefficient of partiallyfilled and full filling are basically the same that the trend has lower when the inputspeed increases. The pump wheel torque coefficient of partially filled is under thewhole filled. Under constant speed, the diameter size of pump is smaller, the torquecoefficient is larger. Calculates that increasing each diameter of100mm, the pumpwheel torque coefficient decreases in the range of about2%.