Design of Parallel Electrical Resistance Tomography System for Measuring Multiphase Flow

ERT (electrical resistance tomography) is effective method for visualization of multiphase flows, offering some advantages of rapid response and low cost, so as to explore the transient hydrodynamics. Aiming at this target, a fully programmable and reconfigurable FPGA (field programmable gate array)-based Compact PCI (peripheral component interconnect) bus linked sixteen-channel ERT system has been presented. The data acquisition system is carefully designed with function modules of signal generator module; Compact PCI transmission module and data processing module (including data sampling, filtering and demodulating). The processing module incorporates a powerful FPGA with Compact PCI bus for communication, and the measurement process management is conducted in FPGA. Image reconstruction algorithms with different speed and accuracy are also coded for this system. The system has been demonstrated in real time (1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%. Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution. The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.