Investigation On Rotameter For Weakening The Viscous Effect In Measurement Of Viscous Fluid

Rotameter is a kind of traditional float type variable area flow meter with the advantages of stabilization, low pressure loss and the ability of measuring the low flow rate. Therefore it is widely used in chemical industry, petroleum, metallurgy, light industry, food industry and other flow industry. The effect of variable viscosity can not be ignored in the factors that impact the flow measurement of rotameter. Therefore, it is significant for improving the measurement accuracy and extending the application fields to weaken the effect of variable viscosity on the measured results.In this paper, the viscous effect on rotameter for the flow measurement of viscous fluid is studied comprehensively. Based on the viscous fluid mathematical model for rotameter, the mechanism reducing the effect of viscous fluid are attempted to investigate. The visbreaking feature structures of rotameter optimized obtain the significant visbreaking function.The main works of this thesis are as following:The present statuses of the research on the mathematical model for rotameter are analyzed. Against the existing problem of the past flow equation for rotameter, the conventional flow equation for rotameter is corrected. Based on the profound study of the working principle of rotameter, the two viscous fluid mathematical models for rotameter based on the viscous friction coefficient of flat and the theory of boundary layer respectively are founded. The computed results of models are verified in consistency with the results obtained from the viscous fluid experiments. Two means for optimizing the geometric parameters of rotameter are put forward on the base of the viscous fluid mathematical models for rotameter.In order to find the more effective mechanism of reducing the viscous effect of fluid on rotameter for the flow measurement, the dynamic simulation platform for rotameter is programmed with the utilization of UDF interface and dynamic mesh technology on the base of computation fluid mechanics,which has the same working principle with the rotameter in reality.Flow field of rotameter is simulated with the dynamic simulation platform of rotameter. After the analysis of distributions of velocity field and pressure field inside rotameter, the phenomenon of vortex field is found at the lower reaches of...