Off- Design Performance Prediction For Cryogenic Small Scale Axial Turbine Using CFD Simulation
The Cryogen based Energy Storage (CES) technology which uses liquid air/nitrogen as an energy carrier has attracted lots of attention recently due to its higher energy density compared to other thermal energy storage technologies. This stored liquid can then be expanded through a Rankine cycle to convert the stored energy to work. Although higher ideal cycle efficiencies can be achieved with this configuration, the effect of the real turbine efficiency can be significant on the overall cycle efficiency. Therefore, it is important to predict the performance of the turbine at cycle operating conditions different from the turbine design operating point. In this work the Mean line method and ANSYS CFD were used to develop a small scale cryogen turbine and predict its performance at different operating conditions using Nitrogen as the working fluid. Results showed that the inlet pressure has the highest impact on the turbine performance as it shifts from the design operating point.
Keywords- Nitrogen ,Cryogenic Axial Turbo-Expander, mean line , CDF Analysis