FPGA-Based System for In-Line Measurement of Velocity Profiles of Fluids in Industrial Pipe Flow

Abstract

The rheology of a fluid flowing in an industrial process pipe can be calculated by combining the pressure drop and the velocity profile that the fluid develops across the tube diameter. The profile is obtained non-invasively through an ultrasound Doppler investigation. Unfortunately, at present, no system capable of real-time velocity profile assessment is available for in-line industrial rheological measurements, and tests are operated by manually moving fluid specimens to specialized laboratories. In this work we present an embedded system capable of in-line and realtime measurement of velocity profile and pressure drop, which enables the automatic rheological characterization of non-Newtonian fluids in process pipes. The system includes all the electronics for the ultrasound front-end, as well as the digital devices for the real-time calculation of the velocity profile. The proposed system is high programmable, low-noise and specifically targeted for industrial use. It is shown capable of producing, for example, 512-point velocity profiles at 45 Hz rate. An application is presented where a sludge fluid, flowing at 600 L/min in a 48 mm diameter high-grade stainless steel pipe, is characterized in real-time with a ±5% accuracy.

FPGA-Based Doppler Frequency Estimator for Real-Time Velocimetry

“…General details of the data processing employed in Pulse-Wave ultrasound can be found in several papers and books, for example References [3,[10][11][12]. Here a brief resume is reported to help readers with the subject, and to highlight the parts most relevant for the comprehension of the proposed algorithm.…”

“…In this work, an improved frequency Doppler estimator is presented. The estimator is implemented in the field programmable gate array (FPGA) included in a real-time ultrasound board [10]. The proposed algorithm takes advantage of the characteristics of both the full centroid and the peak estimators: it features the low calculation effort typical of the peak estimator and the reduced variability typical of the centroid estimator.…”

“…The hardware implementation of the estimator is described and evaluated by experiments. A Newtonian fluid flowing in a pipe is investigated through the Doppler board [10], where peak, full centroid, and the proposed estimator are implemented. The throughput of the three estimators is measured and the quality of the implementation is evaluated by comparing the Doppler frequency estimates calculated in hardware to the corresponding estimates obtained in Matlab.…”

Novel Annular Flow Electromagnetic Measurement System for Drilling Engineering

“…In fact, the current does not exist in the flowpath of the electromagnetic flowmeter, and thus this current is called "virtual current". The distribution of virtual current density is dependent on the flowpath's shape, flow conductivities and the size and position of measuring electrodes [17][18][19][20][21][22]. To simplify the boundary conditions, we suppose that the electronic conductivity of the outer surface of the annular flowpath is much smaller than the flow.…”

“…The loop system working process was as follows [20][21][22]: firstly, the annular flow electromagnetic measurement system was installed at the annular device interface of the loop system; then, the valve was opened and the flow was pumped ,the pressure of the flow was stabilized by passing through the surge tank; then, the flow was followed by flow rate measurement through a standard EMF, whose precision reached 0.5%; finally, the flow flowed through the laboratory annular flow electromagnetic measurement system and returned back to the fluid reservoir. During the experimental process, a personal computer with a data acquisition board named PCIE-8735 was used to measure the signals from the laboratory annular flow electromagnetic measurement system, sensors and transmitters.…”