Model Sensitivity Analysis of Lifetime Predictions for Generation 3 Particle-sCO2 Heat Exchangers

Abstract

A sensitivity analysis is performed to determine which variables play a first order role in determining the lifetime of particle-sCO₂ heat exchangers. A symmetric half-plate geometry based on a hypothetical 16.7 MW commercial scale particle-sCO₂ diffusion bonded IN617 heat exchanger is studied. A reduced-order modelling approach is presented and the steady-state and transient thermal and mechanical performances under nominal Generation 3 concentrated solar power operating conditions are compared against the fully featured model. The defeatured model shows the ability to accurately predict the thermal performance and mechanical lifetime at a fraction of the computational cost, making it a viable option for analysing commercial scale systems. Seven of the model input variables are then parameterized using a Latin Hypercube Sampling method and up to 128 different realizations are simulated. The transient stress results are linearized along stress classification lines in the header ports and used to predict the number of cycles to failure due to fatigue and creep. Sobol indices are generated to relate the cycles to failure to the independent variables studied. The results show that the uncertainty in the creep cycles to rupture data dominates the variation in lifetime predictions.