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

XX. Ocular Manifestations in Nasal and Aural Diseases which Probably, Indicate Involvement of the Sympathetic Nervous System

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Electrolysis of simulated lunar melts

Electrolysis of molten lunar soil or rock is examined as an attractive means of wresting useful raw materials from lunar rocks. It requires only hat to melt the soil or rock and electricity to electrolyze it, and both can be developed from solar power. The conductivities of the simple silicate diopside, Mg CaSi2O6 were measured. Iron oxide was added to determine the effect on conductivity. The iron brought about substantial electronic conduction. The conductivities of simulated lunar lavas were measured. The simulated basalt had an AC conductivity nearly a fctor of two higher than that of diopside, reflecting the basalt's slightly higher total concentration of the 2+ ions Ca, Mg, and Fe that are the dominant charge carriers. Electrolysis was shown to be about 30% efficient for the basalt composition

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

Electrolytic smelting of lunar rock for oxygen, iron, and silicon

Preliminary studies of the electrochemical properties of silicate melts such as those available from heating of lunar mare soils indicate that conductivities are high enough for design of a practical electrolytic cell. The nature and kinetics of the electrode reactions, which involve reduction of Fe(++) and Si(IV) and oxidation of silicate anions as the primary, product-forming reactions, are also satisfactory. A survey of the efficiencies for production (amount of product for a given current) of O2, Fe(sup 0), and Si(sup 0) as functions of potential and of electrolyte composition indicate that conditions can be chosen to yield high production efficiencies. We also conclude that electronic conductivity does not occur to a significant extent. Based on these data, a cell with electrodes of 30 sq m in area operating between 1 and 5V with a current between 1.6 and 3.5(10)(exp 5) A for a mean power requirement of 0.54 MW and total energy use of approximately 13 MWhr per 24-hr day would produce 1 ton of O2, 0.81 ton of Fe(sup 0), 0.65 ton of Si(sup 0) (as Fe(sup 0)-Si(sup 0) alloy), and about 3.5 tons of silicate melt of altered composition per 24 hr. Adjustable distance between electrodes could offer flexibility with respect to feedstock and power source

Aeroacoustic Characteristics of Model Jet Test Facility Flow Conditioners

An experimental investigation of flow conditioning devices used to suppress internal rig noise in high speed, high temperature experimental jet facilities is discussed. The aerodynamic and acoustic characteristics of a number of devices including pressure loss and extraneous noise generation are measured. Both aerodynamic and acoustic characteristics are strongly dependent on the porosity of the flow conditioner and the closure ratio of the duct system. For unchoked flow conditioners, the pressure loss follows conventional incompressible flow models. However, for choked flow conditioners, a compressible flow model where the duct and flow conditioner system is modeled as a convergent-divergent nozzle can be used to estimate pressure loss. Choked flow conditioners generate significantly more noise than unchoked conditioners. In addition, flow conditioners with small hole diameters or sintered metal felt material generate less self-noise noise compared to flow conditioners with larger holes

The Last Stages of Terrestrial Planet Formation: Dynamical Friction and the Late Veneer

The final stage of terrestrial planet formation consists of the cleanup of residual planetesimals after the giant impact phase. Dynamically, a residual planetesimal population is needed to damp the high eccentricities of the terrestrial planets after the giant impact stage. Geochemically, highly siderophile element (HSE) abundance patterns inferred for the terrestrial planets and the Moon suggest that a total of about 0.01 M_Earth of chondritic material was delivered as `late veneer' by planetesimals to the terrestrial planets after the end of giant impacts. Here we combine these two independent lines of evidence for a leftover population of planetesimals and show that: 1) A residual planetesimal population containing 0.01 M_Earth is able to damp the eccentricities of the terrestrial planets after giant impacts to their observed values. 2) At the same time, this planetesimal population can account for the observed relative amounts of late veneer added to the Earth, Moon and Mars provided that the majority of the late veneer was delivered by small planetesimals with radii <10m. These small planetesimal sizes are required to ensure efficient damping of the planetesimal's velocity dispersion by mutual collisions, which in turn ensures that the planets' accretion cross sections are significantly enhanced by gravitational focusing above their geometric values. Specifically we find, in the limit that the relative velocity between the terrestrial planets and the planetesimals is significantly less than the terrestrial planets' escape velocities, that gravitational focusing yields an accretion ratio Earth/Mars~17, which agrees well with the accretion ratio inferred from HSEs of 12-23. For the Earth-Moon system, we find an accretion ratio of ~200, which is consistent with estimates of 150-700 derived from HSE abundances that include the lunar crust as well as mantle component. (Abridged)Comment: accepted for publication in ApJ, 9 pages, 4 figures; minor corrections, additional references adde

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