58763 - Comparison of Compressor Performance Map Predictions to Test Data for a Supercritical Carbon Dioxide Brayton Power Cycle 

Supercritical carbon dioxide (sCO2) Brayton power cycles are typically designed to operate with compressor inlet conditions near the critical point to take advantage of the high density of the fluid at these conditions.  While designing the cycle to operate here improves cycle efficiency, it also creates challenges for designing the compressor and predicting off-design compressor perofrmance due to real gas fluid properties near the critical point.  Multiple compressor performance map evaluation methodologies which incorporate real gas corrections have been proposed in literature with only limited evaluation of the accuracy of these methods compared to operational data from compressors designed for sCO₂ power cycles.  This paper evaluates compressor performance from the 100 kWe Integrated Sytem Test (IST), which was operated at the Naval Nuclear Laboratory, over a range of compressor inlet conditions and rotational speeds relative to one real gas performance map correction methodology and assesses the impact of more complex real gas correction factors proposed in literature in improving the accuracy of off-design performance predictions.  The use of simple real gas correction factors to adjust the compressor performance map results in good agreement with compressor test data.  THe addition of more complex real gas correction factors proposed in literature does not show a strong correlation with improving the accuracy of predicted comrpessor off-design performance.