BIOFUELS RESEARCH - GRC IS EMBARKING ON BIOFUEL STUDIES AS POTENTIAL REPLACEMENT FOR AVIATION FUELS. AS A PART OF THESE STUDIES WE ARE DEVELOPING A HIERARCHICAL SET OF MODELS TO ALLOW PROCESS SIMULATION AND ULTIMATELY OPTIMIZATION OF A KEY BIOFUEL PROCESS - MICROALGAE GROWTH IN OPEN RACETRACK PONDS. THE MODELS RELY ON FUNDAMENTAL BIOLOGY DESCRIPTION FOR A SINGLE MICROALGAE ON THE MICROSCOPIC SCALE, AND ON COMPLETE COMPUTATIONAL TRANSPORT MODELING OF THE ENTIRE SYSTEM ON THE MACROSCOPIC LEVEL. WE ARE SEEKING THE DEVELOPMENT OF A LARGE SCALE NUMERICALLY-BASED MODEL TO ENABLE COMPLETE DESCRIPTION OF THE ALGAE GROWTH PROCESS. THE PROJECT WILL INCORPORATE CLASSICAL TRANSPORT PHYSICS (MOMENTUM, HEAT, MASS TRANSPORT), WITH RADIATION (LIGHT) TRANSPORT MODELS, AND WITH SEPARATELY DEVELOPED MICRO-MACRO STOCHASTICALLY AVERAGED MODELS THAT TAKE INTO ACCOUNT THE ENSEMBLE DISTRIBUTION OF ALGAE CELLS. THE MODELS WILL ALSO INCORPORATE MASS DISTRIBUTIONS OF KEY NUTRIENTS, WASTE PRODUCTS, AND DISSOLVED CARBON DIOXIDE. THE MODELS WILL BE DEVELOPED AND INCORPORATED INTO LARGE SCALE MULTIPHYSICS CODES SUCH AS COMSOL OR OTHER CODES FOR THE STUDY OF PORTIONS OF THE PROBLEM SEPARATELY. IT IS ANTICIPATED THAT FINITE ELEMENT AND/OR VOLUME FORMULATIONS OF THE MODELS WILL BE USED TO DISCRETIZE THE LARGE SCALE APPARATUS TO ENABLE CORRESPONDENCE OF MODEL RESULTS WITH EXPERIMENTAL TESTBEDS AT GRC AND ELSEWHERE. THE MODELS WILL EVENTUALLY BE USED TO (1) CALIBRATE MODEL PARAMETERS FROM CAREFUL EXPERIMENTAL MEASUREMENTS; (2) OPTIMIZE LARGE SCALE ALGAE GROWTH PROCESSES FOR BIOFUEL APPLICATIONS. THE CURRENT STAGE II OF THE PROJECT WAS INITIATED DUE TO THE SUCCESSFUL ACCOMPLISHMENTS OF THE INITIAL WORK UNDER STAGE I. THE CURRENT STAGE WILL FOCUS ON DEVELOPMENT OF LARGE SCALE COMPUTATIONAL MODELS FOR MIXING DEVICES OF OPEN PONDS, INCLUDING STATIC AND DYNAMIC MIXERS, FOR OPTIMIZING TOTAL ALGAE PRODUCTION RATES. DAVID THOMPSON WILL PROVIDE US WITH A FINAL REPORT AND WITH COMPUTATIONAL MODELS AND FINITE ELEMENT MESHES FOR SELECT GEOMETRIES PER NASA S DIRECTION, AS WELL AS BE AVAILABLE FOR TECHNICAL DISCUSSIONS ON THE WORK THROUGHOUT THE DURATION OF THE PROJECT. THE WORK IS ANTICIPATED TO BE PERFORMED AT THE CONTRACTOR'S SITE AND/OR AT GRC, DEPENDING ON GOVERNMENT PREFERENCE. THE PERIOD OF PERFORMANCE IS ESTIMATED TO BE ONE YEAR.