Abstract
In order to clarify the possibility of measuring an oil circulation ratio (OCR), the speed of sound in a mixture of refrigerant/PAG oil has been measured in an HF01234yf refrigeration cycle. As the result, it is found that the speed of sound of the mixture depends on the value of OCR, although it is also affected by temperature and pressure. We think that it is possible for measuring OCR by means of measuring the speed of sound by taking into account the effected of temperature and pressure. In the case of immiscible oil, on the other hand, the measured value of the speed of sound changes significantly when oil drops pass through the sound velocity sensor. By using a mixing chamber, the variation of the speed of sound becomes small.
