CFD Modeling and Comparison With Data From the NIST Reference Spray Combustor

Abstract

Validation of computational fluid dynamics (CFD) predictions for spray combustion application has been a challenging task due to difficulties in both modeling and experimental measurements. However, validation is considered to be an essential exercise for the success of CFD tools in the development of future combustion systems. This paper describes a benchmark spray combustion database collected at National Institute of Standards and Technology (NIST) and validation of a commercial CFD code using these data. Swirl-stabilized combustion of methanol at lean operating conditions in the NIST reference spray combustor facility was selected to be the baseline case for which both measurements and predictions were made. A comparison is presented of CFD predictions with experimental data for droplet size and velocity, and spray volume flux. The agreement between the CFD calculations and the experimental data is generally good once certain adjustments were made to the measured data close to the injector tip. The adjustments were made based on extrapolation from more accurate downstream measurements. Specification of droplet initial conditions for computational modeling that accurately reflect the laboratory conditions remains a significant issue that needs further improvement.