| A simple method is proposed and tested to measure the flow quality in a closed two-phase loop based on the use of a relatively large diameter horizontal tube to stratify the two-phase flow. If the total mass flow rate is known, the flow quality can be reliably determined by measuring the gas phase velocity with a hot-wire anemometer and the void fraction in the horizontal tube. On the other hand, if the total mass flow rate is not known, simplified one-dimensional momentum equations can be solved using the measured void fraction and gas velocity to obtain both the total flow rate and flow quality. This measurement principle was tested using nitrogen gas/water flow loop and good agreement was obtained between the measured and actual flow qualities. Tests were also performed using a compressor-driven refrigerant loop, where the presence of a lubricant oil was determined to have a detrimental effect on the determination of thermodynamic quality based on a heat balance. |
