Investigation On The Property Of Rotameter Sensor And Structure Optimization

Rotameter is a kind of traditional float type variable area flow meter, which has many advantages such as simple structure, working credibly, low pressure loss and stabilization. Besides, it can measure low flow rate. Therefore, it is widely applied in measuring the medium in high temperature, high pressure or corrosive flow. But there are lots of unsettled problems on rotameter. For example, the output of the rotameter sensor is nonlinear, the simulation platform is not perfect, the float of horizontal rotameter vibrates in high flow rate and the rotameter sensor is affected by viscosity of the medium, all of which are important to precision of the rotameter. As a result, it is significant to study its characteristics and optimize its structure.Firstly,through studying the measuring equation of the rotameter, it is pointed out that there is a nonlinear relationship between displacement of the float and the flow rate in the popular rotameter with short pipes ;And through further study on the measuring principle of the rotameter sensor, it is found that the float journey(tapered angle) in short pipes plays an important role on the linearity between displacement of the float and the flow rate ;Through studying internal rule and the relationship, a new method could be presented to solve the nonlinearity of rotameter sensor.Secondly, the software FLUENT of Computational Fluid Dynamics (CFD) that is used in business and the User-Defined Functions (UDF) are introduced simply. Based on the simulation on two-dimension and three-dimension flow field of the vertical rotameter sensor, the factors effect on simulation are analyzed, which includes the inlet condition, the rotation of the float and whether the model has a straight pipe or not. The simulation platform is perfected.Then, the three-dimension flow field of horizontal rotameter sensor is simulated. Through analysis on the simulation results, several optimizing structure of horizontal metal rotameter sensor are proposed and the problem of float vibrating in high flow rate of the horizontal rotameter is solved, the foundation on study and design of horizontal rotameter sensor is settled.Finally, the equipment and project for viscosity experiment are introduced. Three new floats are designed, and three kinds of methylcellulose liquor with viscosity of 31mPa.s, 65mPa.s, 85mPa.s are confected as experimental medium. Through experiments on ten rotameter sensors with different material including widely used CF,...