Flow measurement of fluids with viscosity above 100 cP requires special attention from designers, operators and engineers. In most cases, in order to decrease viscosity, the fluid is heated and the measurement must be reliable under these adverse operating conditions.
Over the past 15 years, ultrasonic meters have become the emerging technology for measuring liquids, including those with high viscosity. However, in these cases, there are challenges in applying the technology, such as:
1) Acoustic transmission capacity of the ultrasonic pulse between the sensors, through fluids with high viscosity and, therefore, high signal absorption;
2) Ability to integrate the different speeds measured by the instrument in each of the acoustic paths, in any flow regime.
The energy absorption of ultrasonic pulses is greater in more viscous fluids than in less viscous fluids, ie it is much more difficult to obtain a suitable signal for measurement in high viscosity fluids. To solve this problem, the proper selection of ultrasonic sensors is essential. Daniel 3804 ultrasonic meters have sensors capable of operating with fluids with a viscosity greater than 1,000 cP. Another aspect to be considered is the flow regime of the fluid to be measured. When a fluid flows through a pipe, it does not have the same flow velocity along the cross section of the pipe. There is influence of the friction of the tube wall on the flow, and therefore, close to the wall, the flow velocity is lower. Farther away from this effect, the central region of the pipe corresponds to the area with the highest flow velocity. With that, a speed profile is formed. The influencing factors are: fluid viscosity and density, average flow velocity, pipe inner diameter, piping arrangement upstream and downstream of the measurement point, and piping internal roughness. Daniel uses in its 3804 ultrasonic meters algorithms from computational, analytical and empirical simulations to characterize the effects of the flow regime, in order to properly calculate the flow.
Daniel meters have excellent performance in measuring the flow of high viscosity fluids. Daniel has carried out intensive research in recent years for the correct characterization of viscous fluid flows and the effect of high viscosity on measurement. Flow measurement is accurate despite the high absorption of ultrasonic pulses and the velocity profile in any flow regime. Fluxo is a representative of Daniel's products for the entire national market.