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Standardized, Compact, and Automated Shock Tube for Fuel Characterization and Modeling

Description:

TECHNOLOGY AREA(S): Air Platform 

OBJECTIVE: The objective of this SBIR is to develop, Test and Validate a standardized, compact, automated and easy-to-use shock tube capable of state-of-art measurements of the ignition-delay-time and fuel pyrolytic and oxidation histories (optical and/or otherwise). The fuel pyrolytic and oxidation intermediate species measured are those involved in key combustion reaction pathways for AF and other DOD propulsion systems, and their measurement enables characterization of fuel combustion chemistry and supports combustion model development efforts. 

DESCRIPTION: Fuel Combustion-chemistry properties determine molecular changes from high-energy-state fuel/oxidizer molecules to low-energy-state product molecules during the energy conversion process in AF and other DOD propulsion systems. Physically accurate and computationally efficient combustion chemistry models [1-3] are a critical part of physics-based modeling and simulation (M/S) tools for developing future generations of AF and other DOD propulsion systems such as solid/liquid rockets, aviation jet engines, and hypersonic scramjets. The capability of measuring fuel combustion chemistry properties such as the ignition delay and the fuel pyrolytic and oxidation intermediate species histories following key reaction pathways is a foundational element for the development and validation of such physically accurate and computationally efficient combustion chemistry models. Presently, the ignition delay and pyrolytic/oxidation species histories are mainly measured using shock-tubes equipped with start-of-art combustion diagnostic techniques (optical or intrusive probes) in research laboratories at leading universities. There are two long-lasting challenges: (1) non-standard facility/instruments and measurement procedures; and (2) expense in time and/or funding to operate such facilities. These shock-tube facilities and related combustion diagnostic instruments have been developed largely under incremental supports from AF (AFOSR) and other DOD 6.1 sources over the past several decades. Although the underlying scientific working principle has long been understood, due to the incremental nature of past development efforts in multiple universities by multiple agencies for different emphases, these facilities/instruments are of a research nature and not standardized, such that there are large variations in facility/instrumentation attributes. Comparing results from different facilities that use somewhat different procedures is often difficult. These facilities are usually expensive to operate, requiring long training times for graduate students or post-doc researchers to become proficient in facility and diagnostics operation. However, after many years of development, the shock-tube technology and associated combustion diagnostic techniques have matured sufficiently [4] to be standardized and transitioned for more applied uses (6.2 and beyond) at governmental research laboratories, such as AFRL, USAFA, or commercial aviation and aerospace industries, to support fuel characterization and fuel combustion-chemistry modeling. Furthermore, such standardized, compact and automated shock-tubes can be developed into a field deployable tool for fueling testing and quality control at fuel depots and major airports. This topic focuses on the transition of the state-of-art research shock-tube setup along with necessary combustion diagnostic techniques to standardized, compact and easy-to-operate instrumentation tools with maximum automation for the fuel characterization and combustion chemistry model development. Proposals must include the all following aspects in an integrated fashion and will be evaluated accordingly: (1) Capable of measuring ignition delay and pyrolytic and oxidation intermediate species histories of sufficient temporal resolution with acceptable uncertainty; (2) Flow initiation process: diaphragm-less systems are highly desired/preferred. The valve opening time and the impact of valve opening process on the shock-propagating flow must be quantified to be adequate for the measurements mentioned above. For any flow initiation approaches, full impacts of the flow initiation process on the shock propagation flow must be sufficiently quantified for making proper measurements mentioned above. (3) The boundary-layer and other non-ideal flow attributes: proposed designs much be able to provide an adequate one-dimensional shock-propagating core flow of sufficient size for the above mentioned measurements. Full impacts of the boundary layer and other non-ideal flow attributes must be sufficiently quantified. (4) Modular design and sufficient optical and probe accesses; and (5) Ease-of-use with maximum automation of operation and measurement processes suitable for laboratory technicians, without requiring highly-skilled research personnel. 

PHASE I: Efforts consist of the following: (a) review state of art shock-tube technologies and associated diagnostic techniques, their capabilities, limitations and uncertainties with respect to earlier stated measurement objectives; (b) propose a creditable design and creditable quantification approaches with sufficient scientific and technical substantiations to address the above elements (1)-(5). A Phase I proposal will not be considered without clearly describing such creditable quantification approaches of sufficient details based on scientific and technical logic, especially for items (2) and (3) stated above; (c) incorporation of needed diagnostic techniques (optical, probes, etc.); (d) formulating a test/validation plan for measuring ignition delay time and key pyrolytic and oxidation species histories for small molecular foundational fuels (CH4, C2H4, C3H8 etc.) and real AF/DOD fuels/fuel blends including but not limited to JP8/Jet-A/JP5, JP10 and RP-2/its derivatives. The proper execution of Items (a)-(d) forms the foundation of the Phase II proposal. Phase I efforts consist of the following: (a) review state of art shock-tube technologies and associated diagnostic techniques, their capabilities, limitations and uncertainties with respect to earlier stated measurement objectives; (b) propose a creditable design and creditable quantification approaches with sufficient scientific and technical substantiations to address the above elements (1)-(5). A Phase I proposal will not be considered without clearly describing such creditable quantification approaches of sufficient details based on scientific and technical logic, especially for items (2) and (3) stated above; (c) incorporation of needed diagnostic techniques (optical, probes, etc.); (d) formulating a test/validation plan for measuring ignition delay time and key pyrolytic and oxidation species histories for small molecular foundational fuels (CH4, C2H4, C3H8 etc.) and real AF/DOD fuels/fuel blends including but not limited to JP8/Jet-A/JP5, JP10 and RP-2/its derivatives. The proper execution of Items (a)-(d) forms the foundation of the Phase II proposal. 

PHASE II: Efforts focus on development and construction of prototype shock-tube system with the required diagnostic tools based on the Phase I design, and the execution of the test and validation plan developed in Phase I. Prototype systems will be delivered to DOD and/or other federal government laboratories and Institutions for testing usage. 

PHASE III: Based on the inputs from the testing usage defined in Phase II, further improve the system capability and develop the system into field deployable systems for fueling testing and quality control at fuel depots and major airports. 

REFERENCES: 

1. Sayak Banerjee, Rei Tangko, David A. Sheen, Hai Wang, C. Tom Bowman, An experimental and kinetic modeling study of n-dodecane pyrolysis and oxidation, Combustion and Flame (2015) 1-19.; 2. Wang, H., Xu, R., Wang, K., Bowman, C. T., Hanson, R. K., Davidson, D. F., Brezinsky, K., Egolfopoulos, F. N. “A Physics-based approach to modeling real-fuel combustion chemistry. I. Evidence from experiments, and thermodynamic, chemical kinetic and statistical considerations,” Combustion and Flame 193, 502-519 (2018). DOI: 10.1016/j.combustflame.2018.03.019.; 3. Xu, R., Wang, K., Banerjee, S., Shao, J., Parise, T., Zhu, Y., Wang, S., Zhao, R., Lee, D. J., Movaghar, A., Han, X., Gao, Y., Lu, T., Brezinsky, K., Egolfopoulos, F. N., Davidson, D. F., Hanson, R. K., Bowman, C. T., Wang, H., A Physics-based approach to modeling real fuel combustion chemistry. II. Reaction models of jet and rocket fuels. Combustion and Flame 193, 520-537 (2018). DOI: 10.1016/j.combustflame.2018.03.021.; 4. Ronald Hanson and David Davidson, Recent advances in laser absorption and shock tube methods for studies of combustion chemistry, Progress in Energy and Combustion Science (2014) 44-1

KEYWORDS: Combustion Chemistry, Pyrolysis, Shock-tube, Ignition Delay, Pyrolytic Pathways, Aerospace Propulsion Systems 

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