Simultaneous Pressure and Temperature Measurements on Helium in the High Speed Rotating Frame
As part of continuing thermodynamic and hydrodynamic studies of liquid helium in the high speed rotating frame, we have successfully measured pressures and temperatures simultaneously at the periphery of a 0.5 metre diameter rotor at tip speeds up to 65(m/s). For these measurements a Siemens KPY14 absolute pressure transducer and Southampton miniature diode thermometer have been used. This paper describes the calibration of the pressure transducer and its performance characteristics in centrifugal acceleration fields up to 2200 “g”. The change in sensitivity of the transducer after many thermal cycles, between 4.2 K and 300 K, and repeated acceleration to 65(m/s) is less than 0.5%. Pressure and temperature measurements under high speed rotation are discussed by comparing the observed variations, as a function of tip speed, with predicted values of temperature and pressure using available thermodynamic data.
KeywordsEntropy Mercury Enthalpy Helium Compressibility
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