Irvine, S A; Burns, R M; Nov 21, 2005; 9 pp.; In English Contract(s)/Grant(s): Proj-4847 Report No.(s): AD-A442054; AFRL-PR-ED-TP-2005-454; No Copyright; ONLINE: http://hdl.handle.net/100.2/ADA442054; Avail.: CASI: A02, Hardcopy

In recent years, Government and industry have both documented considerable interest in developing reusable, long-life, liquid hydrocarbon fueled rocket engines. However, in order to design an engine with these characteristics, a more complete understanding of the fuel's liquid-side fluid characteristics, while in engine regenerative-cooling channels, is needed. To add to this required understanding, experiments are currently being conducted at the Air Force Research Laboratory's High Heat Flux Facility (HHFF), located at Edwards AFB, CA. The HHFF is designed to explore many fuel related rocket engine design considerations (e.g., high aspect ratio cooling channels, various fuel thermal stability issues, material compatibility, heat transfer capability, effects related to dissolved oxygen or specific sulfur species contained within the fuel, etc.) Recently, the Air Force has been studying RP-2 (Ultra-Low Sulfur RP-1) in order to establish an accurate baseline for future experiments in the HHFF. These experiments were conducted using low overall heat transfer coefficients and wall temperatures. This paper will present and discuss the results of recent Air Force experiments at HHFF. DTIC

Fuels; Heat Flux; Heat Transfer; Rocket Engines; Thermal Stability

20060014797 Sandia National Labs., Albuquerque, NM USA

Guidance on Risk Analysis and Safety Implications of a Large Liquefied Natural Gas (LNG) Spill Over Water

Hightower, Mike; Gritzo, Louis; Luketa-Hanlin, Anay; Covan, John; Tieszen, Sheldon; Wellman, Gerry; Irwin, Mike; Kaneshige, Mike; Melof, Brian; Morrow, Charles; Ragland, Don; Dec 2004; 168 pp.; In English; Original contains color illustrations Report No.(s): AD-A442674; No Copyright; ONLINE: http://hdl.handle.net/100.2/ADA442674; Avail.: CASI: A08, Hardcopy

While recognized standards exist for the systematic safety analysis of potential spills or releases from LNG (Liquefied Natural Gas) storage terminals and facilities on land, no equivalent set of standards or guidance exists for the evaluation of the safety or consequences from LNG spills over water. Heightened security awareness and energy surety issues have increased industry's and the public's attention to these activities. The report reviews several existing studies of LNG spills with respect to their assumptions, inputs, models, and experimental data. Based on this review and further analysis, the report provides guidance on the appropriateness of models, assumptions, and risk management to address public safety and property relative to a potential LNG spill over water. DTIC

Environment Pollution; Hazards; Liquefied Natural Gas; Risk; Safety; Spilling; Water

20060015238 Georgia Inst. of Tech., Atlanta, GA USA

Real-Time Control for Optimal Liquid Rocket Combustor Performance

Zinn, Ben T; Lubarsky, Eugene; Neumeier, Yedidia; Dec 2005; 11 pp.; In English Contract(s)/Grant(s): F49620-03-1-0172 Report No.(s): AD-A443134; No Copyright; ONLINE: http://hdl.handle.net/100.2/ADA443134; Avail.: CASI: A03, Hardcopy

To meet the goals of this program, a 'smart' liquid fuel injector, whose spray pattern can be modified by controlling the flow rate of two coaxial, counter swirling, oxidizer (air) streams that control the characteristics of the fuel spray, was developed and tested under cold-flow conditions and in combustion experiments. The cold flow experiments have clearly shown that it's possible to drastically change the characteristics of the fuel spray by changing the relative flow rates of the two oxidizer streams. The performance of this 'smart' injector was studied in two combustors that were developed for this study. The first has one 'smart' injector at the center of its injector plate and the second seven such injectors uniformly distributed on the injector plate. Both combustors have quartz walls to allow extensive access for optical diagnostics. Open loop tests with the single injector combustor showed that the 'smart' injector can suppress longitudinal combustion instabilities by varying the split between the flow rates of the two controlling oxidizer streams (see AIAA papers 2003-4937, 2004-1034 and ASME Paper # GT2005-69138). DTIC

Combustion Chambers; Control Rockets; Fuel Injection; Liquid Fuels; Propellants; Real Time Operation

20060016364 NASA Marshall Space Flight Center, Huntsville, AL, USA, Streamline Numerics, Inc., Gainesville, FL, USA

Validation of a Pressure-Based Combustion Simulation Tool Using a Single Element Injector Test Problem

Thakur, Siddarth; Wright, Jeffrey; [2006]; 1 pp.; In English; 3rd International Workshop on Rocet Combustion Modeling, 12-15 Mar. 2006, Paris, France Contract(s)/Grant(s): NNM05AA87C; No Copyright; Avail.: Other Sources; Abstract Only

The traditional design and analysis practice for advanced propulsion systems, particularly chemical rocket engines, relies heavily on expensive full-scale prototype development and testing. Over the past decade, use of high-fidelity analysis and design tools such as CFD early in the product development cycle has been identified as one way to alleviate testing costs and to develop these devices better, faster and cheaper. Increased emphasis is being placed on developing and applying CFD models to simulate the flow field environments and performance of advanced propulsion systems. This necessitates the development of next generation computational tools which can be used effectively and reliably in a design environment by non-CFD specialists.

A computational tool, called Loci-STREAM is being developed for this purpose. It is a pressure-based, Reynolds-averaged Navier-Stokes (RANS) solver for generalized unstructured grids, which is designed to handle all-speed flows (incompressible to hypersonic) and is particularly suitable for solving multi-species flow in fixed-frame combustion devices.

Loci-STREAM integrates proven numerical methods for generalized grids and state-of-the-art physical models in a novel rule-based programming framework called Loci which allows: (a) seamless integration of multidisciplinary physics in a unified manner, and (b) automatic handling of massively parallel computing.

The objective of the ongoing work is to develop a robust simulation capability for combustion problems in rocket engines. As an initial step towards validating this capability, a model problem is investigated in the present study which involves a gaseous oxygen/gaseous hydrogen (GO2/GH2) shear coaxial single element injector, for which experimental data are available. The sensitivity of the computed solutions to grid density, grid distribution, different turbulence models, and different near-wall treatments is investigated. A refined grid, which is clustered in the vicinity of the solid walls as well as the flame, is used to obtain a steady state solution which may be considered as the best solution attainable with the steady-state RANS methodology. From a design point of view, quick turnaround times are desirable; with this in mind, coarser grids are also employed and the resulting solutions are evaluated with respect to the fine grid solution. Author

Combustion; Injectors; Simulation; Pressure; Full Scale Tests; Rocket Engine Design

Source: NASA