Novel partial admission radial compressor for CO2 applications

• A novel partial admission radial turbo-compressor is proposed.
• The concept aims at reduction of non-stage losses through reduction of shaft speeds.
• Optimistic CFD predictions of around 80% base stage efficiency are presented.
• For reasonable stage efficiency of the compressor proper design of the diffuser will be critical.
• Commercial CO2 applications at close to critical pressures are favorable for the concept.

A novel partial admission turbo compressor concept is proposed as an alternative to a conventional radial oil-free CO2 compressor. The concept aims at the improvement of the overall performance through the reduction of the non-stage windage and cooling losses enabled by compression at significantly reduced shaft speeds. Transient CFD analysis gives fairly optimistic prediction of more than 80% of base stage efficiency at around 1.4 total pressure ratio. The study shows potential for efficiency improvement by optimization of the shape and number of blades. The conceptual compressor may be an interesting alternative for commercial CO2 applications operating at close to critical pressures, provided that the deceleration of the gas in the diffuser is efficient.