Investigation On Rotameter For Raising The Precision In Measurement Of Fluid

Rotameter is a type of trad itional f loat var iable area f low m eter. It has the advantage of simple structure,cheap price,highly stabilization, small pressure loss and the cap acity in m easuring the low flow rate fluid. So it is wid ely applied in petroleum , light industry , coal ,metallurgy, food sanitation ,m editation and other industry fields. There are m any factors that affect ro tameter measuring accuracy, in order to im prove the precision and expand its application field, this paper doe s research on several as pects su ch as improving sensor m athematical m odel and mechanical structure, in stalling con ditioner to im prove the installation conditions, correcting a ngle pos ition detec tion m odel, developing th e intelligen t inf ormation processing systems.The works undertaken in the paper are as following:A design method of flowmeter porous conditioner based on velocity distribution law was proposed. The proportion of targ et velocity w as acquired by m eans of computing regional velocity distribution of fully developed flow field. CFD numerical simulation was modeled to get the velocity distribution inside each area of disto rted flow field, which can modify the flow field by specifying flow area. Test this design under the lim it installation c onditions such as horizontal rotameter and ultra short front straight section. The results demonstrate that the new design of flow conditioner can be used to correct current bias caused by elbow pipes and reduce the unbalance of float force. It can b e concluded that th is design is a signifi cant referenc e for improving the measurement accuracy of flowmeter.Influenced by the electric field edge e ffect and the accuracy of manufacture, the measurement accuracy of current ratio capacitance angular displacement sensor is low. The paper designed a precision angle calib ration device based on grating technique which can nonlinearly correct the output an gle by intelligent m ethods and raise an intelligent ratio mathematical model. It approved that the novel calibration device can improve the measurement accuracy of su ch capacitance angle from 2.5 to 1.5 grade level.A method of partition leas t-square nonlinear correction which was suitable for flow output perform ance of float flow meter was proposed as well. During the verification of float flowm eter, it de vides calibration nu mbers acco rding to th e statistical regularity, then makes a second-order nonlinear correction in the interval by the least sq uare fitting. It not only im proves the speed of lower com puter but also avoids Longe phenomenon. The residual error can be minimized and the measurement accuracy is improved obviously as well.Analyzed the existing problem s in deducing the m athematical equation for rotameter . Directing at the past f low m odel for rotam eter, used fluid m echanics formula in consideration of energy loss caused by fluid viscous drag to model orifice plate Rotameter f low se nsor, com pared the the oretical sim ulation resu lts with the calculated results of traditional cone tube Rotameter by experiments.