Modeling three reacting flow systems with modern computational fluid dynamics.

摘要

Computational fluid dynamics (CFD) modeling and analysis were used in three projects: solar CO2 conversion modeling, improved coal combustion modeling using STAR-CD, and premixed combustion modeling. Each project is described below.; The solar CO2 conversion modeling project involved CFD simulations of a prototype solar CO2 converter that uses sunlight to dissociate CO2 into CO and O2. Modeling was used to predict the performance of this prototype converter using three CFD software packages, and involved predicting the flow, heat transfer, and chemical kinetics. Accuracy was determined by comparison of model predictions and experimental data. Parametric modeling studies were performed in order to better understand converter performance and limitations. Modeling analysis led to proposed operational and design changes meant to improve converter performance. Modeling was performed to quantify the effects of proposed design modifications and operational adjustments. Modeling was also used to study the effects of pressure, some geometric design changes, and changing from pure CO2 to a CO2/He mixture. The insights gained from these modeling studies have played a key role in improving the performance of this process.; The second project involved the implementation of advanced coal models into STAR-CD, a commercial CFD program. These coal models were originally developed for PCGC-3, a code developed at Brigham Young University. This project involved modifying modern PCGC-3 coal combustion and gasification models so that they could be incorporated into STAR-CD. Models implemented included a coal set-up subroutine, and coal reactions models for devolatilization, char oxidation, and vaporization. Each implemented model was tested to verify its accuracy by comparison of model predictions with experimental data. All implemented coal submodels were validated by comparison between overall modeling predictions and experimental data. These implemented coal models increased the capability of STAR-CD to model coal combustion and gasification systems.; The third project was to assemble previously obtained experimental data on lean, premixed natural gas combustion. Velocity, temperature, and species concentration measurements were previously taken throughout a laboratory-scale gas turbine combustor using advanced laser diagnostics. However, these data were taken by different investigators at BYU over the course of 10 years, and the data were scattered through several publications, theses, and dissertations. This third project was to compile these data into a central location for analysis and distribution. This data set is excellent for validation of any comprehensive combustion model, and is now accessible to the public.