Two temperatures can be detected in a hot gas laden with water droplets. The lower one is the temperature read by a sensor immersed in the flow. This measurement is affected by significant evaporative cooling resulting in readings much below the real gas temperature. The higher one is the temperature of the gas. The difference between these two temperatures is proportional to the water volumetric fraction in the flow. On this basis, a new technique for the measurement of the water volumetric fraction is proposed. The results are compared with a conventional measurement technique based on optical methods. A novel approach to the gas temperature measurement is also introduced. The sensing device is kept at temperatures exceeding the Leidenfrost transition and therefore it is insensitive to the presence of the water droplets. Independent measurement techniques developed at the Evaporative Cooling Sensor Accuracy Test (ECSAT) facility provide the data to validate the measurements obtained with the Above Leidenfrost Temperature and Evaporative Cooling (ALTEC) sensor.

Issue Section:
Bubbles, Particles, and Droplets
Keywords:
two-phase flow, drops, cooling, evaporation, temperature distribution, flow visualisation, Droplet, Evaporation, Flow, Heat Transfer, Measurement Techniques
Topics:
Drops, Sensors, Temperature, Water, Flow (Dynamics), Evaporation, Evaporative cooling
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