Mapping Liquid Mass Fractions in Optically Dense Rocket Combustion Chambers

ABSTRACT: This Small Business Innovation Research Phase 1 project will evaluate the feasibility of utilizing X-Ray tomography to map liquid mass fractions in optically dense sprays. High fuel flow rate nozzles are ubiquitous in rocket propulsion, power generation, and transportation. In these high flow rate nozzles, the local mass fraction of fuel is directly proportional to the local heat release rate, and therefore it impacts both the combustion stability and engine efficiency. However, it is not currently possible to fully elucidate the structure of these dense sprays, particularly in a reacting environment, where conventional optical diagnostics is impossible. During Phase I, En"Urga Inc. will demonstrate the feasibility of utilizing X-Ray tomography for obtaining the structure of fuel sprays in a non-reacting environment. During Phase II, a prototype system will be developed and evaluated in hot fire condition. There are two issues of intellectual merit that will be addressed during the Phase I work. The first issue is the development of an X-Ray tomography system to measure path-integrated extinction from high mass flow rate sprays. The second is the development of an advanced algorithm that will provide local mass concentrations from the path integrated measurements. These two novel features enable an accurate characterization of liquid mass fractions in optically dense sprays. BENEFIT: There are two primary commercial applications for the proposed spray diagnostic. The first is in the characterizing the near injector structure of dense sprays prevalent in the automotive and aerospace industries. Characterization of near injector structure is extremely important for the development and evaluation of newer fuel injectors, which provide greater efficiency and lower pollution. Typical customers in this area include aircraft engine manufactures such as Rolls-Royce, GE, and Pratt and Whitney, as well as automotive manufacturers and their suppliers such as GM, Eaton, Ford, Bosch, Cummins, Chrysler, Detroit Diesel, Caterpillar, John Deere, etc. The second commercial application for the proposed diagnostics is in industrial burners. There are several high flow industrial burner nozzles using fuels ranging from coal slurry to furnace oil. These nozzles cannot be currently evaluated due to the fact that they produce sprays that are very dense. The proposed system will make the fuel flow pattern from such nozzles amenable to investigation for the first time.