The double-sensor conductivity probe is one widely used technique for measuring local time-averaged parameters in two-phase flows. Although a number of studies have been carried out in the past, a good understanding of the uncertainty of this technique is still lacking. This paper aims to address this gap by performing a systematic and comprehensive study on the measurement uncertainty of the probe. Three types of uncertainties are analyzed: that of measurands, of the model input parameters, and of the mathematical models. A Monte Carlo uncertainty evaluation framework simulating the measuring process is developed to link various uncertainty sources to the time-averaged two-phase flow quantities output by the probe. Various sensitivity studies on model uncertainties, model input uncertainties and their propagations are performed. The uncertainties in primitive time measurement are studied by specially designed tests. Results show that there are random errors and systematic delays in the interfacial time measured by the probe. These errors are correlated by bubble velocity, DAQ frequency and signal processing threshold. The analysis shows that a large uncertainty could exist in the velocity measurement for high-velocity-low-frequency conditions. The errors in primitive length measurements are quantified by both experiments and analysis. It shows that the flow-induced deflection and vibration are unnoticeable in the test section for a superficial liquid velocity up to 4 m/s. Another test is performed using a high speed camera to study the flow disturbance caused by a double-sensor probe. Test results show that the probe has minimal disturbance to the upstream region of the measuring location, though bubbles have been diverted by the probe downstream.

双传感器电导率探针是一种广泛使用的技术，用于测量两相流中的局部时间平均参数。尽管过去已经进行了许多研究，但是仍然缺乏对该技术不确定性的充分理解。本文旨在通过对探头的测量不确定度进行系统而全面的研究来解决这一差距。分析了三种类型的不确定性：被测量的不确定性，模型输入参数的不确定性和数学模型的不确定性。建立了模拟测量过程的蒙特卡洛不确定性评估框架，以将各种不确定性源与探头输出的时间平均两相流量相联系。对模型不确定性，模型输入不确定性及其传播进行了各种敏感性研究。通过专门设计的测试来研究原始时间测量中的不确定性。结果表明，探针测量的界面时间存在随机误差和系统性延迟。这些误差与气泡速度，DAQ频率和信号处理阈值相关。分析表明，在高速低频条件下，速度测量可能存在较大的不确定性。通过实验和分析来量化原始长度测量中的误差。结果表明，在表层液体速度高达4 m / s的情况下，在测试段中没有注意到由流动引起的偏转和振动。使用高速相机执行另一项测试，以研究由双传感器探头引起的流量扰动。