To accurately predict the flow field of compressor cascades involving adverse pressure gradients and corner separation flows, an improved Spalart-Allmaras (S-A) turbulence model was developed. Based on the actual structural characteristics of the cascade corner region, the wall distance in the turbulence model was redefined. Correction terms for helicity and adverse pressure gradient were introduced into the transport equation of turbulent eddy viscosity, along with adjustments to model coefficients and inlet parameters. The enhanced turbulence model was applied to NACA 65-009 cascades, and the Ensemble Kalman Filter (EnKF) data assimilation method was employed to calibrate correction coefficients and inlet boundary conditions using experimental static pressure coefficient data at 50% and 5.4% span. Results demonstrate that the modified S-A model significantly improves prediction accuracy for corner separation flows in compressor cascades. Compared with the original S-A model, the overall change rate of the prediction deviation at the 50% and 5.4% span sections exceeds 80%. The improved model also shows substantially smaller discrepancies when validated against independent experimental data excluded from calibration. Validation under multiple operating conditions confirms the enhanced generalization capability of the modified S-A turbulence model across different operating conditions.

Battery safety problems in abnormal thermal situations such as operation in cold/hot environment, thermal management defunction and thermal runaway attract addressing attentions. Here from the battery safety perspective, a coupled thermal-electrochemical-mechanical phase-field model is developed for crack propagation and lithium dendrite growth, thus to illustrate the underlying mechanisms of interfacial failure and dendrite evolution in lithium metal all-solid-state batteries (ASSBs) under abnormal thermal situations. The effects of inter-cell temperature distribution direction and magnitude, stacking pressure, and interfacial roughness at on crack propagation and dendrite growth are systematically investigated. Originating from augmented strain energy density by thermal expansion, crack propagation is much accelerated at negative temperature differences (NTD), which provide more space for dendritic growth as well as inducing stronger longitudinal evolution directionality. The fastest dendrite distance at NTD increases much faster than that under positive temperature difference (PTD) for significantly enhanced electrochemical driving force. Under isothermal or PTD conditions, an applied stacking pressure below than 30 MPa can inhibit the crack propagation and fastest dendrite evolution. However, at NTD, any applied stacking pressure contributes to crack propagation and lithium dendrite growth. More initial defects increase the crack region area, meanwhile the crack propagation depth is shortened due to weakened von Mises stress and strain energy density. Considering both crack propagation and fastest dendrite evolution, applying a suitable stacking pressure below 10 MPa to improve the Li/solid electrolyte (SE) interface is desired, thus to reduce the interfacial failure and possibility of short circle. The findings offer an alternative comprehensive perspective to evaluate the battery safety under abnormal thermal conditions, and could provide rational guidance for design and development highly reliable ASSBs.