Combustion Modeling for Direct Fired Supercritical CO2 Power Cycles

The supercritical CO2 (sCO2) Brayton cycle is gaining interest across a variety of power generation applications due to its potential for providing higher efficiencies. The range of industrial applications include: industrial waste and heat recovery, coal and nuclear power plants, and renewable energy sources such as solar thermal and fuel cells. Direct fired sCO2 cycle loops require combustors that operate beyond the critical point of CO2 in a flow regime that is not well understood. Development of efficient combustor designs at these conditions presents many challenges due to the lack of design and simulation tools that properly account for the reaction kinetics, turbulent mixing and real fluid property variations. Our proposed work here addresses these deficiencies. Statement of How this Problem or Situation is Being Addressed: The design of combustors for sCO2 power cycles presents many challenges since the physics of the reaction kinetics, turbulent flame interactions and real fluid properties in this flow regime are not well understood. Under this project an advanced turbulent combustion model was developed to address complex reacting flow environments under real fluid conditions. Accurate kinetic modeling under these conditions was also be addressed in partnership with the Georgia Institute of Technology. Under the Phase I effort the framework of the new modeling approach was developed and demonstrated. This project will extended an advanced modeling formulation for application to real fluids and multi-stream mixing environments. The model was then be demonstrated for a current SCO2 power cycle combustor geometry. Under the Phase II program with new modeling formulation will be rigorously validated with respect experimental data for multiple experimental configurations and cases. Commercial Applications and Other Benefits:The sCO2 Brayton cycle is gaining interest across a variety of power generation applications including nuclear, fossil fuel, waste heat as well as solar thermal and fuel cells due to its potential for providing efficiencies up to 5% points higher than a steam Rankine cycle. However, the design of efficient combustors for direct fired systems is complex. Our work here provides a high-fidelity design tool that permits accurate performance predictions in this thermodynamic regime and enables the commercialization of optimal combustor designs for these more efficient power generation systems.