Nozzle performance evaluation considering non-equilibrium condensation under complex weather conditions for guiding compressed air energy storage system optimization

Compressed air energy storage enhances grid resilience by integrating intermittent renewable energy. During compression, humid air containing droplets and particles is prone to condensation due to temperature–pressure imbalances between compressor blades under natural climate variations (foggy, rainy, and hazy), which induces phase change and degrades compressor performance. The objective of this study is to systematically compare the effects of homogeneous and heterogeneous condensation on compressor performance, with particular emphasis on the role of heterogeneous condensation nuclei. A one-dimensional Laval nozzle model is employed to simulate non-equilibrium condensation under different heterogeneous particle numbers. First, the validation of the blend droplet growth model is verified by comparing the experimental data and numerical results. Second, the varied weather conditions are converted into distinct inlet boundary conditions, with key parameters focusing on particulate matter types, and concentrations. Finally, nozzle performance is evaluated. The results indicate that heterogeneous condensation produces a higher droplet mass fraction than homogeneous condensation, leading to intensified phase change processes and increased latent heat release. As a consequence, the kinetics loss coefficients increase markedly, accompanied by enhanced irreversible losses and a reduction in thermal efficiency. Moreover, increasing the number of condensation nuclei strengthens heat and mass transfer associated with non-equilibrium condensation, further amplifying kinetic energy losses and deteriorating thermal efficiency. These findings provide important insights into the mechanisms by which non-equilibrium condensation degrades compressor performance and offer guidance for improving compressor efficiency and reliability through effective control of heterogeneous condensation.