Development of the Compact Jet Engine Simulator From Concept to Useful Test Rig

NASA had a goal to develop a set of modeling tools for designing next generation civil transport aircraft with reduced noise, emissions and increased fuel efficiency by 2016. To verify the models, a database of aerodynamic and acoustic data was needed for an unconventional flying wing design that was predicted to meet the goals. A Compact Jet Engine Simulator (CJES) was needed as the jet source for the 5.8% scale model. Ultra-Compact Combustor Technology from the Air Force Research Laboratory was used to reduce the conventional burner acoustic test rigs down to the required scale size. The Air Force design had to be modified for compactness and safety standards for testing in a wind tunnel. The combustor liner, plug-vane and flow conditioner components were built in-house at the NASA Langley Research Center. The CJES units were built and integrated incorporating a control system for operation in the NASA Langley Low Speed Aeroacoustic Wind Tunnel. The operational envelope of the combustor was mapped, and improvements were developed to moderate combustor instability tones and rig flow noise. The final concept was unchanged, but the internal hardware evolved throughout the process. The Compact Jet Engine Simulator as a standalone unit demonstrated acceptable acoustic rig performance compared to the Boeing Low Speed Acoustic Facility rig. An integrated aerodynamic and acoustic test using the Compact Jet Engine Simulators was performed in the 14- by 22- Foot Subsonic Tunnel in 2012/13, and the results proved the goals were met with a score of 96%. The Compact Jet Engine Simulator is modular and can be used to test subsonic engine nozzles in the bypass ratio range from 5 to 10. The CJES units can be used for acoustic testing or studying the integration of the engine propulsion flow with an aircraft. This thesis focuses on the design and hardware development of the CJES units for which the author was primarily responsible

Flame Holder System

A flame holder system includes a modified torch body and a ceramic flame holder. Catch pin(s) are coupled to and extend radially out from the torch body. The ceramic flame holder has groove(s) formed in its inner wall that correspond in number and positioning to the catch pin(s). Each groove starts at one end of the flame holder and is can be shaped to define at least two 90 degree elbows. Each groove is sized to receive one catch pin therein when the flame holder is fitted over the end of the torch body. The flame holder is then manipulated until the catch pin(s) butt up against the end of the groove(s)

Investigation of Flow Conditioners for Compact Jet Engine Simulator Rig Noise Reduction

The design requirements for two new Compact Jet Engine Simulator (CJES) units for upcoming wind tunnel testing lead to the distinct possibility of rig noise contamination. The acoustic and aerodynamic properties of several flow conditioner devices are investigated over a range of operating conditions relevant to the CJES units to mitigate the risk of rig noise. An impinging jet broadband noise source is placed in the upstream plenum of the test facility permitting measurements of not only flow conditioner self-noise, but also noise attenuation characteristics. Several perforated plate and honeycomb samples of high porosity show minimal self-noise but also minimal attenuation capability. Conversely, low porosity perforated plate and sintered wire mesh conditioners exhibit noticeable attenuation but also unacceptable self-noise. One fine wire mesh sample (DP450661) shows minimal selfnoise and reasonable attenuation, particularly when combined in series with a 15.6 percent open area (POA) perforated plate upstream. This configuration is the preferred flow conditioner system for the CJES, providing up to 20 dB of broadband attenuation capability with minimal self-noise

Aerodynamic Performance and Acoustic Measurements of a High-Lift Propeller in an Isolated Configuration

A series of aerodynamic performance and acoustic measurements has been made on a high-lift propeller intended for utilization on a distributed electric propulsion (DEP) aircraft. Tests were performed in the NASA Langley Low Speed Aeroacoustic Wind Tunnel (LSAWT), which has recently undergone a capability enhancement for the testing of small propellers/rotors and small unmanned aircraft system (UAS) platforms. The objectives of this testing campaign are two-fold: first to demonstrate the facility capabilities for performing small propeller aeroacoustic testing, and second to compare experimental measurements with computational fluid dynamic (CFD) predictions and CFD-based acoustic predictions of the tested propeller configurations for tool development and validation purposes

Acoustic Characterization of Compact Jet Engine Simulator Units

Two dual-stream, heated jet, Compact Jet Engine Simulator (CJES) units are designed for wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. The newly fabricated CJES units are characterized with a series of acoustic and flowfield investigations to ensure successful operation with minimal rig noise. To limit simulator size, consistent with a 5.8% HWB model, the CJES units adapt Ultra Compact Combustor (UCC) technology developed at the Air Force Research Laboratory. Stable and controllable operation of the combustor is demonstrated using passive swirl air injection and backpressuring of the combustion chamber. Combustion instability tones are eliminated using nonuniform flow conditioners in conjunction with upstream screens. Through proper flow conditioning, rig noise is reduced by more than 20 dB over a broad spectral range, but it is not completely eliminated at high frequencies. The low-noise chevron nozzle concept designed for the HWB test shows expected acoustic benefits when installed on the CJES unit, and consistency between CJES units is shown to be within 0.5 dB OASPL

Hybrid Wing Body Aircraft Acoustic Test Preparations and Facility Upgrades

NASA is investigating the potential of acoustic shielding as a means to reduce the noise footprint at airport communities. A subsonic transport aircraft and Langley's 14- by 22-foot Subsonic Wind Tunnel were chosen to test the proposed "low noise" technology. The present experiment studies the basic components of propulsion-airframe shielding in a representative flow regime. To this end, a 5.8-percent scale hybrid wing body model was built with dual state-of-the-art engine noise simulators. The results will provide benchmark shielding data and key hybrid wing body aircraft noise data. The test matrix for the experiment contains both aerodynamic and acoustic test configurations, broadband turbomachinery and hot jet engine noise simulators, and various airframe configurations which include landing gear, cruise and drooped wing leading edges, trailing edge elevons and vertical tail options. To aid in this study, two major facility upgrades have occurred. First, a propane delivery system has been installed to provide the acoustic characteristics with realistic temperature conditions for a hot gas engine; and second, a traversing microphone array and side towers have been added to gain full spectral and directivity noise characteristics

Journal of the Military Service Institution of the United States.

No more published.Vol. 24 has supplement: Proceedings of the twentieth anniversary of the Military service institution of the United States MDCCCXCIX (19 p.).Editors: 1890. T.F. Rodenbough and J.C. Bush -- 1891-93, W.L. Haskin and J.C. Bush -- 1894-Mar. 1899, J.C. Bush -- July 1899-May 1901, W.H. Powell -- July 1901-Feb. 1913, T.F. Rodenbough -- Mar. 1913-Dec. 1917, J.N. Allison.Quarterly, 1879-88 (forming 1 vol. annually); bi-monthly, 1859-1917 (forming 1 vol. annually up to and including 1894; 2 vols. annually beginning with 1895).Vols. 3, 11-61, 1882, 1890-1917, have imprint: Governor's Island.Vol 1, no. 1, issued 1879.Mode of access: Internet.Vol. 3 (1882) and vols. 11-61 (1890-1917) have imprint: Governor's Island.General Index for v. 35-49.Index for v. 1-34 in v. 34