Experimental Study of Two-Phase Critical Flow for Supercritical CO₂ application

The major benefits are relatively higher efficiency under moderate turbine inlet temperature which significantly reduced materials and maintenance related issues, and simple layout and physically compact power plant size due to small turbo-machinery and heat exchangers. Predicting the leak flow rate is imperative to maintain the high performance of S-CO₂ power cycle. Thus, experiment of two-phase critical flow was conducted to obtain the validation data for transient simulation model while special attention is given to the turbo-machinery seal design. The experiment results identified that the temperature at nozzle exit sharply decreases under - 10ºC due to the Joule-Thomson effect after expansion through the nozzle. Therefore, a care is needed when using a labyrinth seal for the S-CO₂ turbomachinery. To identify the icing phenomenon inside of labyrinth seal geometry, further experiments with labyrinth seal geometry nozzle under various conditions will be conducted.