Analytical Simulation of the Champagne Effect in CAES Power Plants

The champagne effect is a two-phase flow instability that could occur in a hydraulically compensated compressed air energy storage (CAES) power plant. This effect is a direct result of the solubility of high-pressure air in water. The buoyancy effect resulting from air bubbles in the compensating water shaft could lead to a pressure imbalance which causes the water to accelerate. A thorough understanding of the dynamics of this effect and control measures for avoiding deleterious consequences is necessary if commercial CAES power plants are to be successfully built and operated. The governing physical mechanisms of the champagne effect have been incorporated into a computer simulation model. The model is based on a one-dimensional, drift flux representation of the two-phase flow in the water compensating shaft. The model includes a comprehensive simulation for the rate of release of air from solution during the flow transient. Preliminary results of the analysis suggest that by proper design of the system, including a U-bend and flow restriction, the champagne effect should not be a major deterent to the commercialization of this type of CAES power plant.