Dynamic characteristics of flow meters for fuel consumption measurement in ships

Abstract

The dynamic characteristics of various flow meters for fuel consumption measurement aboard shipswere evaluated. The flow rate was measured using the Korea Research Institute of Standards and Science (KRISS) oil flow standard system using K-oil(density : 0.804 g/cm3, viscosity : 3.679 cSt), which has similar fluid properties as diesel oil. The flow meters were tested in a test bed that simulated the vibration conditions in ships. The vibration conditions were established in accordance to vibration standard IEC 60068-2-6 as follows: a±0.7g acceleration and 30 Hz frequency. The K-factors (mL/pulse) of various flow meters (PD meter, turbine flow meter, Coriolis flow meter, and ultrasonic flow meter) were obtained for various flow rates (60 L/h ~ 300 L/h). The PD meter, Coriolis flow meter, and ultrasonic flow meter were found to have almost constant Kfactors according to the flow rates. However, the K-factor of the turbine flow meter was reduced at a low flow rate owing to bearing friction in the turbine blade. The flow rate errors of the PD meter, Coriolis flow meter, and ultrasonic flow meter were found to be under ±0.5 % with and without vibration. However, the flow rate error of the turbine flow meter was approximately -4.3 % at a low flow rate (60 L/h) owing to the friction effect. The Coriolis flow meter had the lowest flow rate error (< 0.1%) according to the flow rate. The vibration influenced the flow rate error of the Coriolis flow meter at high flow rates owing to its measuring principle. However, the difference in flow rate errors was a negligible value (0.05 %) with and without vibration. Therefore, we confirmed that the PD meter, turbine meter, Coriolis flow meter and ultrasonic flow meter could be used for measuring flow rates in ships with a ±0.5 % flow rate error.