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Description
The liquid PbLi and PbBi alloys have been selected as one of the most promising coolant materials in fusion blanket and accelerator driven subcritical (ADS) reactor, respectively. The velocity distribution in the flow channel of blanket will greatly affect the efficiency of heat transfer and materials corrosion, so it’s necessary to carry out relevant researches to obtain the detailed flow field. Ultrasonic Doppler velocimetry (UDV) is considered as one of the best methods measuring opacity fluid.
In the process of UDV measurement, the measuring accuracy is one of the most important problems and large bias is observed in measuring results. The reason for the bias is that there are three factors, intersection between measuring volume and wall, refraction of the ultrasonic, ringing effects of piezoelectric element, which mainly influence the measuring accuracy. However, it’s well known that the ultrasonic is a kind of mechanical wave, which will lead to vibration of the medium in the process of propagation. The vibration of medium will cause disturbance to flow field and then lead to measuring bias, so it should be also considered as a key factor in flow field measurement. However, the influence of vibration is usually ignored and no researches were performed on it. Hence, it’s necessary to research about it.
In this paper, ANSYS analysis is adopted to investigate the effect of vibration of medium. The vibration of medium leads to the acoustic pressure variation of fluid which can deduce the vibration velocity. The acoustic pressure in flowing fluid is calculated through numerical simulation and the two factors, excitation voltages and backing layer, are analyzed. The results show that a large disturbance velocity up to 10mm/s is generated in heavy liquid metal and it’s proportional to excitation voltages. The disturbance is slowly growing up with the thickness of backing layer increasing from 2mm to 6mm, but no obvious variation is obtained when the thickness of backing layer is larger than 6mm. So, it’s very meaningful for bias analysis in flow field measurement based on the results. Besides, it can support the design of UDV sensor and conduct the parameters setting in experiments.
| Eligible for student paper award? | Yes |
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