Transient Thermo-Structural Analysis of a Throttle Valve Operated With sCO2

This paper presents thermo-structural analyzes performed on a throttle valve operated with CO2 at supercritical conditions. In more detail, the study started with the thermal characterization of the steady-state behavior under different load conditions. During this phase, a numerical methodology for the evaluation of thermal maps was defined based on a loosely coupled Conjugate Heat Transfer approach that exploits a flow network and a 3D finite element thermal solver. A decoupled CFD analysis helped defining the thermal loads on the sealing system around the stem. The following step was dedicated to the analysis of a typical start-up ramp. The start-up sequence was built by linearly increasing the sCO2 flow from zero to the design value and then holding it constant until the metal temperature reaches the steady state. The performed thermo-structural analysis allowed the calculation of the relative displacements between the stem and the valve casing along the entire transient process.