Measurement and Modeling of Surface Coking in Fuel-Film Cooled Liquid Rocket Engines

ABSTRACT: Designing an efficient and effective film cooling system to protect critical components of modern rocket engines requires a significant number of challenges to be addressed. Complicating the already difficult hydrodynamic challenges, thermal cracking of hydrocarbon fuels is always accompanied by coke formation. The coke deposits on the combustor and nozzle walls reduces heat fluxes and can have complicated effect on regenerative heating of the fuel flowing through the outer channels. The overall goals of this SBIR project are 1) to develop new in-situ measurement techniques for surface coking and 2) develop accurate validated models for surface coking. Both these goals are required to provide appropriate inputs for thermal management systems on modern rocket engines which could operate at pressures upwards of 200 bars. In Phase I, CFDRC will team up with Purdue University to systematically develop an integrated approach of combining experiments with model development for soot deposition on walls. New approaches for developing in-situ measurement of surface soot deposition will be investigated. In Phase II, in-situ measurement techniques will be implemented and demonstrated and additional validation will be carried out for the soot deposition models.; BENEFIT: The capability of accurately modeling soot deposition on combustor walls and their effects on heat-transfer and thermal management of the rocket engine/combustors will have a wide appeal to gas-turbine manufacturers, rocket-engine manufacturers as well as those companies involved in further development of scramjet technology and industrial applications such as internal combustion engines, and chemical process industries where fouling due to surface coking is often a significant maintenance issue. Companies such as General Electric, Pratt & Whitney, Allied Signal, Solar Turbines, and Williams will be interested in this technology to address surface fouling issues inside combustion chambers. Launch and hypersonic vehicles primes such as Lockheed Martin and Boeing, and Rocket engine manufactures such as Aerojet Rocketdyne would also need the next-generation technologies for accurately measuring and modeling surface fouling coke deposition and its effect on heat transfer inside the combustion chamber and nozzle.