[Deepu*et al., 5(7): July, 2016] ISSN: 2277-9655 IC™ Value: 3.00 Impact Factor: 4.116 http: // www.ijesrt.com© International Journal of Engineering Sciences & Research Technology [549] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY DESIGN ANALYSIS FOR A ROTAMETER USING CFD Deepu C N * , Yogesh Kumar K J ,Dr V Seshadri * M.Tech Student, Thermal Power Engineering, Maharaja Institute of Technology, Mysore Assistant Professor, Department of Mechanical Engineering, Maharaja Institute of Technology, Mysore Professor (Emeritus), Department of Mechanical Engineering, Maharaja Institute of Technology, Mysore DOI: 10.5281/zenodo.57043 ABSTRACT Rotameter is a variable area type of flow meter used to measure the flow rate of liquids and gases .In the present study design and analysis of Rotameter performance is done using ANSYS FLUENT 14 software. Validation of CFD methodology is done by using flow through pipe in a turbulent flow. K-ω-SST model was found to be best suited for this class of flows. In the design of Rotameter assuming CD as 2.4 and maximum flow rate of 100 lpm, preliminary design of a Rotameter has been done for the flow of water. After simulation using CFD flow rate obtained from CFD is not same as that from the preliminary designed values .Hence it is concluded that coefficient of drag is also dependent on diameter ratio. Improved design methodology of Rotameter is presented by considering effect d/D on coefficient of drag, by using a correlation derived on the basis of CFD computations. The effect of upstream disturbance (like valves) at various locations on the performance of Rotameter is analyzed using validated CFD methodology. It is concluded that has as long as the locations of disturbance is more than 5Din upstream of the inlet , the error in the measurement will be less than 2% . The validated CFD methodology is used to analyse the effect of density and viscosity of fluid on the accuracy of metering by a Rotameter .A need for the development of correlation for viscosity correction factors are highlighted. The analysis also demonstrated that a Rotameter designed and calibrated for water flow can be used for measurement of air flow at different pressures as long as correction factor are applied. The maximum error of in such cases will be order of 5%. The study has demonstrated that a validated CFD methodology can be used to accurately predict the performance of Rotameter even under non -standard conditions KEYWORDS:Rotameter, Coefficient of Drag, Drag Force.flow rate. INTRODUCTION Flow meter is a device which measures the flow rate of any liquid in a closed or open conduit. Flow metering is the one of the features in most of the industrial process. A wide variety of flow meters are used for different applications. Some of these devices meters are Obstruction type flow meters like orifice meter, venturi meter and flow nozzles etc.as well as special meters like turbine flow meter, ultrasonic flow meter and electro-magnetic flow meter etc. Specific design like Coroilis meter, Doppler velocity meter etc.Rotameter is one kind of flow meter which is a variable area type of flow meter .It consists of vertically placed glass tapered tube and metallic float free to move up and down within the tube .The metering tube placed vertically along with fluid stream with a larger diameter at the top, fluid enters at the bottom of the tube and passes over the float and leaves at the top. The maximum diameter of float is approximately same as the inlet diameter of the tube, when fluid enters at the bottom of tube float start rises in the tube. When there is no flow in the tube float is settled at the bottom of metering tube, fluid enters at the bottom of the tube the buoyant effect will act on the float but float density higher than the fluid, position of float still in the bottom of tube. Increasing the flow rate of fluid until buoyant effect of fluid greater than weight of float and then float starts to rise in the tube, it can be move up to top end of tapered tube. When buoyant force and drag force of the fluid on the float is same as that of weight of float, then the float is in dynamic