NASA Scientific and Technical Aerospace Reports

implantation of analog-to-digital conversions taking place at the antenna. RF amplifiers will, however, remain analog for the
foreseeable future.
Derived from text
Avionics; Radio Frequencies; Analog to Digital Converters; Civil Aviation; Computer Programs; Signal Processing;
Intermediate Frequencies
20060002324 Aviation Management Associates, Inc., Springfield, VA, USA
Role of Multi-Mode Multi-Function Digital Avionics in the Future NAS
Harrison, Mike; Wargo, Chris; Proceedings of the Fifth Integrated Communications, Navigation, and Surveillance (ICNS)
Conference and Workshop; November 2005; 8 pp.; In English; See also 20060002231; Original contains color illustrations;
No Copyright; Avail.: CASI: A02, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document
Current avionics are generally: not interoperable across CNS modes and national standards; expensive to upgrade and
certify; not easily reconfigurable for new functions and/or modes; and not able to provide user-selected integration of C, N,
S and management functions. The number of waveforms (both new and legacy) is beginning to overwhelm ability to fit aircraft
with new capabilities. A new, cost-effective methodology to certify avionics is needed (both initial and subsequent for added
waveforms). The objective is to develop an architecture and prototype for multi-function multi-mode digital avionics
(MMDA) that demonstrate: interoperability with international standards and operational modes; low life-cycle cost to
equip/modify; compliance with existing and next generation airground and air-air CNS requirements & functions; and
compliance with redundancy, certification, security and safety standards.
Derived from text
Avionics; National Aviation System; Pulse Communication
07
AIRCRAFT PROPULSION AND POWER
Includes primary propulsion systems and related systems and components, e.g., gas turbine engines, compressors, and fuel systems;
and onboard auxiliary power plants for aircraft. For related information see also 20 Spacecraft Propulsion and Power; 28 Propellants
and Fuels; and 44 Energy Production and Conversion.
20060001862 CFD Research Corp., Huntsville, AL USA
Combustion LES Software for Improved Emissions Predictions of High Performance Gas Turbine Combustors
Black, David Lee; Meredith, Karl V.; Khosla, Sachin; Rani, Sarma L.; Smith, Clifford E.; Sep. 1, 2005; 125 pp.; In English;
Original contains color illustrations
Contract(s)/Grant(s): N00421-04-C-0002; Proj-CFDRC-8503/8
Report No.(s): AD-A440401; No Copyright; Avail.: CASI: A06, Hardcopy
Low emissions of CO, NOx, and unburned hydrocarbons (UHC) are a difficult challenge in the design of new military
gas turbine combustors. Simulation tools that can predict emissions are needed to reduce the cost of producing improved, low
emissions combustor designs. In this SBIR, CFD) Research Corporation (CFDRC) continued to develop combustion Large
Eddy Simulation (LES) techniques to create a high fidelity tool for predicting emissions. The LES code was improved by the
development and implementation of a new multi-step assumed PDF method that accounts for more detailed kinetics with
turbulent chemistry interactions. This new method enables efficient turbulent combustion CFD) calculations for both steady
state Reynolds Averaged Navier Stokes (RANS) and LES with multi-step global mechanisms. Tabulation methods were
implemented and tested for improved computational efficiency. Improvements to the existing combustion models and inlet
boundary conditions for LES were also performed. In addition to the new turbulent combustion models, the capability to
generate the necessary global mechanisms from detailed reaction mechanisms was developed. The final code was validated
against benchmark experimental data, and applied to the Rolls-Royce JSF combustor. Validation cases included both premixed
and diffusion flames covering a broad range of flame conditions. Although much progress was made in this Phase II effort,
continued work is needed to make the new multi-step assumed PDF model robust and practical. In particular, a new solver
for the species transport equations needs to be implemented to reduce run times by a factor of two or more.
DTIC
Combustion; Combustion Chambers; Gas Turbines; Hydrocarbons
26