Experimental and Numerical Study of Supercritical Carbon Dioxide Flow Through Valves

Abstract

The supercritical carbon dioxide (sCO2) Brayton cycle shows advantages such as high efficiency, compactness, and low capital cost. These benefits make it a competitive candidate for futuregeneration powerconversion cycles. In order to study this cycle, valve characteristics under sCO2 flow conditions must be studied. However, the traditional models for valves may not be accurate due to the real gas property of sCO2. In this study, this problem was studied both experimentally and numerically. A small valve was tested in the authors’ experiment facility first to provide validation data. For this valve, numerical predictions of mass flow rate agree with experimental data. Then, simulations were scaled up to valves in a real powercycle design. The traditional gasservice valve model fails to predict mass flow rate at lowpressure ratios. A modification was proposed to improve the current gasservice valve model by changing the chokedflow check.