CRAFT Tech At The 2019 ASME Turbo Expo

CRAFT Tech will be organizing a session and presenting at the 2019 ASME Turbo Expo in Phoenix, AZ.

Dr. Kevin Brinckman will be presenting on “Numerical Simulation of Non-Equilibrium Condensation in Supercritical CO2 Compressors.” Dr. Ashvin Hosangadi will be organizing the same session: “Compressors for sCO2 Power cycles – near-critical Point considerations.” This session will be held on Wednesday, June 19th between 4:00-5:30PM.

Abstract from Dr. Brinckman’s talk:

There is increasing interest in supercritical CO2 processes, such as Carbon Capture and Storage technologies, and electric power production, which require compressors to pressurize CO2 above the critical point. For supercritical compressor operation close to the critical point there is a concern that the working fluid could cross into the subcritical regime which could lead to issues with compressor performance if condensation was to occur in regions where the fluid dropped below the saturation point. To assist designers in evaluating compressor performance, a simulation capability is presented for modeling non-equilibrium condensation in trans-critical CO2 processes. The nonequilibrium framework involves the solution of a discrete droplet phase coupled to the continuum gas phase to track droplet nucleation and growth. This framework has been implemented within the CRUNCH Computational Fluid Dynamics (CFD) code that has been extensively validated for simulation at near critical conditions with an accurate real fluid framework and preconditioned numerics that permits efficient treatment of numerical stiffness providing accurate predictions near the critical point.

Results of predictions using classical nucleation theory to model homogeneous nucleation of condensation sites in  supersaturated vapor regions are presented. A non-equilibrium phasechange model is applied to predict condensation on  the nuclei which grow in a dispersed-phase Eulerian droplet framework. Model validation is provided against experimental data for condensation of supercritical CO2 in a De Laval Nozzle including the Wilson line location. The model is then applied for prediction of condensation in the compressor of the Sandia test loop at supercritical inlet conditions and results compared to earlier equilibrium phase-change predictions to evaluate nonequilibrium effects.

 

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