Study Of Viscosity Effect On Rotameter

In flow industry, the fluid is almost all low Reynolds number fluid, so Ratometer, which is used to measure low Reynolds number fluid, is extensive used. Ratometer is a kind of variable area flow meter, and has such features as simple structure, low cost, convenient operation and installation, stable operating characteristics a. Especially the metal tube rotameter , because of the strong material, which can be used to measure the high pressure and temperature , corrosive fluid, is one of the most important flow meters in process control field. The effect of variable viscosity can not be ignored. Many experts and scholars have been concerned on searching for the viscosity influence law of rotameter and correction curves. This paper had been studied rotameter as well, based on CFD method.The fluid is turbine oil, which belongs to newtonian fluid. The experiments of orifice rotameter on variable temperature oil calibration apparatus were done. Based on viscous fluid theory of the boundary layer and flow resistance, the experiment data was analyzed to study the feature of viscosity effect of DN80 orifice rotameter. The experiment data of DN80 orifice rotameter was compared to DN25 orifice rotameter, to analyze the otherness of viscosity effect between two kinds.Based on viscous fluid theory of the boundary layer and fluid flow, studied the effect of meshing, viscous model and wall function on computed result, the two dimensional axisymmetric model of orifice rotameter and design conditions were obtained. Based on this computation model, using the CFD method, simulated and researched the effect of viscosity on measurement of orifice rotameter. Through the flow field analysis, researched the regular pattern and principle of viscosity effect on measurement of orifice rotameter.Compared the simulation result and flow field of DN80 orifice rotameter to DN25, researched the similarity and otherness of the flow field variation between the two kinds of rorameter, and studied the reason of variation.These methods applied in viscosity experiment and and studying viscosity effect presented in this paper can be extended to the design and application of other type flow meter.