Experimental investigation and data-driven modeling of nanofluid pool boiling under rotational hypergravity
摘要
The coupling effects of rotational hypergravity (1–3.16 g) and nanoparticle concentration (0–0.015 wt.%) on the nucleate pool boiling heat transfer of Al₂O₃–water nanofluids were experimentally investigated using a custom-built centrifugal platform. Three machine-learning algorithms (RF, SVM, XGBoost) were further employed to develop high-fidelity predictive models. Contrary to the monotonic deterioration reported in previous literature for pure fluids, this study identifies a distinct non-monotonic enhancement–deterioration trend in the heat transfer coefficient (HTC). The HTC peaks at approximately 1.41 g (buoyancy-assisted bubble detachment dominating) but deteriorates by up to 25.5% at 3.16 g due to hypergravity-induced sedimentation that overrides Brownian diffusion and forms a compact thermal resistance layer. Nanoparticle concentration exhibits a complex non-linear impact: intermediate concentrations (0.0025–0.0075 wt.%) cause surface clogging and performance decline, whereas the optimal concentration of 0.015 wt.% yields maximum HTC enhancement (> 60 kW/m2 K) which is hypothesized to reconstruct the heating surface with strong capillary wicking. Among the ML models, XGBoost demonstrated exceptional predictive fidelity with R2 = 0.998, RMSE = 1.2%, and MAE = 0.8%, far outperforming classical semi-empirical correlations. These findings provide robust mechanistic insights and a reliable predictive tool for aerospace thermal management systems under variable gravity conditions.