Research On Ultrasonic Sensor For Two Phase Flow Measurement

As a novel sensor technology, the ultrasonic has special advantages in medical detection and flow measurement.When the ultrasound spreads in the fluid,there is no influence on the flow field and no pressure loss.At the same time,when the sensor is installed outside of the pipeline,the direct contact can be avoided.The ultrasonic technology applied in the two phase flow measurement involves in many aspects, so the article just makes a research on the ultrasonic sensors.The research includes the design of the excited signal and the deal with the received one.The article applies the LFM to the system, meanwhile, makes the pulse compression technology to deal with the received signal.The LFM has a considerable time-bandwith product, which can improve the energy of the transmit singal and coordinate with the pulse compression, improving the system discrimination and the SNR. The research is separated into three parts as followed:1 The article makes a research on the speciality of the LFM and the pulse compression by simulation, choosing a suitable LFM and pulse compression method.2 The hardware system is designed based on FPGA. The whole system consists of the launch module, receiving module and data acquisition and processing module.3 The static experiment is done to verify the performances of the sensor with round rods and fits out the relation between the diameter of the round rods and the loss of the voltage.The result shows that there is an obvious advantage over the measurment of the two phase flow with coordination of the LFM, the pulse compression and the sensor. At the same time, many factors such as the attenuation of the ultrasound, diffraction, twice reflection, the matching of the excited signal and the sensor will have influences on the preference of the system.