Research On Flow Fieldanalysis And Parameter Matching Of Hydraulic Dynamometer

Dynamometers are used to measure power of combustion engines, turbines andother power machines. Power is the main parameter that assesses the quality of powermachines. It evaluates the operational capability, economy, reliability and otherparameters of the power machines by measuring the power. hydraulic dynamometer,electric eddy-current dynamometer, electrical dynamometer are common. Hydraulicdynamometer is used widely by which has a simple structure, easy operation, goodregulating performance and smooth feature. However, the current research onhydraulic dynamometer focused on intelligent and precise control system as well asexperimental platforms. The research of the hydraulic dynamometer structure and itsinternal flow field is also less. Therefore, understanding its internal flow field and therelationship between the parameters is a matter of concern.In recent years, large-scale application of computer technology solvesengineering problems, but also makes the numerical simulation of fluid machinerypossible. The method greatly improves the efficiency of the design, but also theinternal flow of the dynamometer can be intuitively understood.Considering its physical structures is not feasible, this paper use the simulationmethods to simulate the flow field conditions of hydraulic dynamometer. First, theflow turbulence state and theoretical model are analyzed. Then stator and rotor modelsare established with UG and imported into Fluent software to analyze the flow field.By extracting parameters and using regression analysis to find out the relationshipbetween various parameters, those provide the basis for the design of hydraulicdynamometers. The main contents of this paper are those.Firstly, the three-dimensional models are built according to the product, and thenit is imported into Fluent software for numerical simulation. The simulation iscompleted though selecting the appropriate parameters and calculation methodaccording to turbulence characteristics.Secondly, the blade angle of rotor and stator is changed from30°-90°, Then itsinternal flow between rotor and stator is simulated. According to the simulation resultreasonable adjustment are used to rebuild and re-simulate. The flow field simulationresults and values of power absorption of the different blade angle are gained. Ensurethat each blade angle is constant, the new values are gained by changing watertemperature that flow into the hydraulic dynamometer. The temperature is298K, 310K,320K. Further another twenty-seven set of data are obtained by re-simulation.Thirdly, the regression analysis of numerical results is explained. this paper isabout internal flow field distribution of hydraulic dynamometer. All kinds of cloud ofvelocity gradient, pressure, and the value of torque are gained. Through analysis andcomparison of multiple groups, the relationship among the torque, blade angle andwater temperature are obtained by linear regression and curve fitting of regression.The better parameters are blade angle55°and water temperature310K. Thereasonable result of the regression is verified by using simulation methods.