An Experimental Study on the Characteristics of Oval Gear Flowmeters
Ki Won Lim
Abstract:
An experimental investigation was conducted into the characteristics of an oval gear flowmeter (OGF) using various fluids with different viscosities such as liquid butane (0.17 cP), gasoline (0.40 cP), spindle oil (12.0 cP), etc. Three OGFs were adopted that have a 50 mm inner diameter and ± 0.2 % repeatability in the range of 3 and 17 m³/h . The top and side clearances were measured to see their effects on its overall characteristics. The leakage flow through the clearance between its rotor and casing body was determined by liquid viscosity and the size of the clearance. The amount of the leakage flow has been both measured experimentally and estimated theoretically with the calculated velocity profile in the clearance. In the experiment, the piston prover, the gravimetric, and the volumetric calibrators have been employed. Then, the uncertainty of each calibrator was evaluated as being within ± 0.1 % in flow quantity determination using an evaluation procedure that follows ISO recommendation. It was found that the characteristics of OGFs depend on the viscosity of fluid and the magnitude of clearance. Also, the characteristics, when measured with other liquids than water, can be predicted based on the water measurement results. As the results of this study, a correction equation of ( δQ = 0.272 In µ – 0.0113 is proposed to predict the flow measurements of other liquids by utilizing a correction method developed in this study.
