The application of cryogenic refrigeration in various applications of superconductivity such as HTS cables, HTS motors, SMES and so on, requires a controlled flow of the cryogens to the superconducting mass. The flow control of the cryogens necessitates the use of a pre-calibrated flow meter to monitor the flow rates and hence maintaining the necessary refrigeration. This paper describes a method to calibrate a Cryogenic Turbine based Volumetric Flow Meter (CTVFM) using sub-cooled liquid nitrogen. The experimental setup along with the procedure has been explained. The paper also discusses the practical issues faced during experiments and remedies adopted to overcome them. Further, the data acquisition (DAQ) system used during the experiment for precise logging of values is discussed. The numerical analysis of the calibration data is carried out and a suitable curve fit along with an equation is obtained to calculate the flow rate from output current of the flow meter transmitter.

中文翻译：

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基于超冷液氮的基于涡轮机的低温体积流量计（CTVFM）的标定及其实际问题的解决方案

在超导性的各种应用（例如HTS电缆，HTS电机，SMES等）中应用低温制冷，需要控制制冷剂向超导物质的流动。制冷剂的流量控制需要使用预先校准的流量计来监控流量，从而保持必要的制冷。本文介绍了一种使用过冷的液氮校准基于低温涡轮的体积流量计（CTVFM）的方法。实验设置以及该过程已得到说明。本文还讨论了实验过程中面临的实际问题以及为克服这些问题而采取的补救措施。此外，讨论了在实验过程中用于精确记录值的数据采集（DAQ）系统。