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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Pilot Deployment of the LDSD Parachute via a Supersonic Ballute

The Low Density Supersonic Decelerator (LDSD) Project required the use of a pilot system due to the inability to mortar deploy its main supersonic parachute. A mortar deployed 4.4 m diameter supersonic ram-air ballute was selected as the pilot system for its high drag coefficient and stability relative to candidate supersonic parachutes at the targeted operational Mach number of 3. The ballute underwent a significant development program that included the development of a new liquid methanol-based pre-inflation system to assist the ballute inflation process. Both pneumatic and pyrotechnic mortar tests were conducted to verify orderly rigging deployment, bag strip, inflation aid activation, and proper mortar performance. The ballute was iteratively analyzed between fluid and structural analysis codes to obtain aerodynamic and aerothermodynamic estimates as well as estimates of the ballute's structural integrity and shape. The ballute was successfully flown in June 2014 at a Mach number of 2.73 as part of the first LDSD supersonic flight test and performed beyond expectations. Recovery of the ballute indicated that it did not exceed its structural or thermal capabilities. This flight set a historical precedent as it represented the largest ballute to have ever been successfully flown at this Mach number by a NASA entity.

Tanner, Christopher L.↗
NASA NTRS2017

Advanced Noise Abatement Procedures for a Supersonic Business Jet

Supersonic civil aircraft present a unique noise certification challenge. High specific thrust required for supersonic cruise results in high engine exhaust velocity and high levels of jet noise during takeoff. Aerodynamics of thin, low-aspect-ratio wings equipped with relatively simple flap systems deepen the challenge. Advanced noise abatement procedures have been proposed for supersonic aircraft. These procedures promise to reduce airport noise, but they may require departures from normal reference procedures defined in noise regulations. The subject of this report is a takeoff performance and noise assessment of a notional supersonic business jet. Analytical models of an airframe and a supersonic engine derived from a contemporary subsonic turbofan core are developed. These models are used to predict takeoff trajectories and noise. Results indicate advanced noise abatement takeoff procedures are helpful in reducing noise along lateral sidelines.

Berton, Jeffrey J.↗
NASA NTRS2016

Reconstructed Parachute System Performance During the Second LDSD Supersonic Flight Dynamics Test

NASA’s Low-Density Supersonic Decelerators project (LDSD) has developed and tested four new aerodynamic decelerator technologies for future Mars missions: two attached toroidal inflatable decelerators, a ballute, and a large supersonic parachute. On June 8, 2015, the project conducted a high-altitude, supersonic flight test of a 30.5-meter supersonic Ringsail (SSRS) canopy at the US Navy’s Pacific Missile Range Facility (PMRF) on Kauai, HI. This test, the second in a series of Supersonic Flight Dynamics Tests (SFDT-2), allowed the LDSD project to test the deployment and performance of its parachute decelerator system in the wake of a representative test vehicle (a 4.7-meter aeroshell and 6-meter toroidal inflatable aerodynamic decelerator) at conditions relevant to Mars entry for the second time. The parachute decelerator system consisted of the SSRS main parachute and a 4.4-meter ballute (called the parachute deployment device, or PDD) for its extraction. The ballute was mortar-deployed at a Mach number of 2.78 and a dynamic pressure of 493 Pa, and inflated with the aid of a water-methanol based gas generator. After flying in the wake of the test vehicle for ten seconds, the PDD was released and allowed to extract the main parachute pack. The SSRS reached line-stretch at a Mach number of 2.37 and dynamic pressure of 602 Pa. Following full inflation, the propagation of a tear in the canopy led to the failure of the parachute skirt band and to the subsequent failure of the vent band. The test vehicle was instrumented with load sensors, inertial sensors, and high-speed and high resolution cameras that provided data on the performance of the PDD and SSRS through deployment, inflation, and flight. This paper describes the resulting reconstructed behavior of the PDD and SSRS during deployment and inflation, their aerodynamic performance on SFDT-2, the failure of the SSRS shortly after full inflation, and the LDSD project’s investigation into its underlying causes.

O'Farrell, Clara↗
NASA NTRS2020

Supersonic Technology Concept Aeroplanes for Environmental Studies

The International Civil Aviation Organization is considering new environmental standards for future supersonic civil aircraft. NASA is supporting this effort by analyzing several notional, near-term supersonic transports. NASA’s performance, noise, and exhaust emission predictions for these transports are being used to inform a larger study that will determine the global environmental and economic impact of adding supersonic aircraft to the fleet beginning this decade. A supersonic business jet with a maximum takeoff gross weight of 55 tonnes is the focus of this paper. A smaller business jet weighing 45 tonnes is also discussed. Both airplanes use supersonic engines derived from a common contemporary commercial subsonic turbofan core. Aircraft performance, airport-vicinity noise, and exhaust emissions are predicted using NASA tools. Also investigated are some of the anticipated behaviors and requirements of these aircraft in the commercial airspace. The sensitivity of noise to system uncertainties is presented and alternative engine studies are discussed.

Berton, Jeffrey J.↗
NASA NTRS2020

Advanced Supersonic Parachute Inflation Research Experiment Preflight Trajectory Modeling and Postflight Reconstruction

The Advanced Supersonic Parachute Inflation Research and Experiments (ASPIRE) was a series of sounding rocket flights aimed at understanding the dynamics of supersonic parachutes that are used for Mars robotic applications. The 2012 Mars Science Laboratory (MSL) had a successful deployment of a supersonic parachute, but based on post-flight analysis of parachute margins, the ASPIRE project was created as a risk-reduction program to improve quantification of these margins and qualify a supersonic parachute for Mars 2020, the follow-on mission to MSL. The first sounding rocket (SR01) flight of ASPIRE occurred near Wallops Island, Virginia on Oct. 4, 2017 and demonstrated the successful deployment and inflation of a MSL build-to-print parachute in flight conditions similar to the 2012 MSL mission. The ASPIRE SR02 and SR03 were successful follow-on flights on Mar. 31, 2018 and Sep. 7, 2018 that demonstrated the new, strengthened supersonic parachute designed for the Mars 2020 project. The SR02 and SR03 parachuteswere targeted to 100% and 140% of the expected flight limit load for Mars 2020 to confirm new margins expected from the strengthened parachute. Prior to all flights, a multi-body flight dynamics simulation was developed to predict the parachute dynamics and was used, in conjunction with other tools, to target Mars-relevant flight conditions. After each flight, the on-board data were used to reconstruct the flight trajectory and to validate the pre-flight dynamics simulation. Post-flight analysis showed that all three tests achieved their targeted conditions and pre-flight modeling bounded the key performance metrics for the parachute. This paper describes the flight mechanics simulation, post-flight reconstruction, and the reconciliation process used to validate the flight models.

Soumyo Dutta↗
NASA NTRSDate not supplied

Flametube Evaluation of a Lean-Lean Combustor Concept Developed for Supersonic Cruise Aircraft

Gaseous emissions were measured in single-cup flametube tests of an advanced low-NOx combustor concept at simulated supersonic cruise conditions. The combustor concept is a low technology readiness level (TRL), lean front-end design developed under the NASA Fundamental Aeronautics/Supersonics project to minimize NOx emissions at supersonic cruise. The flametube conditions matched or approached combustor conditions at supersonic cruise, with combustor inlet temperatures up to 920 K, inlet pressures up to 19 bar, and combusted gas temperatures up to 2,120 K. Whether these conditions met or just approached supersonic cruise conditions depended on the type of engine the combustor would be installed in. Two types of engines were considered here: a “derivative” engine based on a current technology and an “advanced” engine with a higher operating pressure ratio and higher temperature limits. For the “derivative” engine, the combustor is expected to be at least close to meeting the NASA NOx emissions goal of 10 g-NOx/kg-fuel at supersonic cruise. However, with the higher combustor inlet and flame temperatures of the advanced engine, NOx emissions are expected to be well above the goal.

combustion↗
NASA NTRS2022

Validation of a High-Fidelity Supersonic Parachute Inflation Dynamics Model and Best Practice

The parachute inflation dynamics (PID) of a Disk-Gap-Band (DGB) parachute system travelling at supersonic velocities in the high-altitude Earth atmosphere is simulated using a high-fidelity, multiphysics, massively-parallel computational framework. The sensitivity of the simulation results with respect to critical modelling and simulation parameters, including the fluid mechanical governing equations (Euler vs Navier-Stokes with RANS turbulence closure vs Navier-Stokes with LES turbulence closer), the interaction between the flow and the suspension lines (accounted for vs not accounted for), the dynamics of the payload (restrained vs free), and the material model of the heterogeneous fabric canopy (Saint-Venant Kirchoff vs mechanics-informed multiscale neural network), is extensively investigated. The parameter investigation is enabled by advancements to the state-of-the-art in the modelling and simulation of the supersonic parachute inflation process, which are presented as part of the computational framework. The predictive quality of the computational framework in the context of supersonic PID is validated by comparison of the simulation results with the experimental results from NASA’s Advanced Supersonic Parachute Research (ASPIRE) project. Through the validation, best practices for the modelling and simulation of supersonic PID are developed and proposed.

Rabinovitch, Jason↗
NASA NTRS1960

III. Supersonic cruise aircraft

The aviation world is on the threshold of sustained supersonic flight at a level of efficiency approaching the best of our subsonic aircraft. This potential has been recognized in the concept of the B-70. Now the supersonic transport is on the horizon. The supersonic transport represents a great technical challenge. Not only must this vehicle have the aerodynamic efficiency of the subsonic bomber, but it must also embrace: (a) the overriding element of passenger safety, (b) the problem of community acceptance (noise), and (c) economy of operation. This paper will be devoted primarily to the aerodynamic problems of large supersonic aircraft as related to performance. Smaller vehicles have been considered in part II of this compilation. The stability and control problems are of equal importance but are not discussed herein.

Supersonic aircraft↗
NASA NTRS1951

Preliminary Investigation of a New Type of Supersonic Inlet

A supersonic inlet with supersonic deceleration of the flow entirely outside of the inlet is considered. A particular arrangement with fixed geometry having a central body with a circular annular intake is analyzed, and it is shown theoretically that this arrangement gives high pressure recovery for a large range of Mach number and mass flow and therefore is practical for use on supersonic airplanes and missiles. For some Mach numbers the drag coefficient for this type of inlet is larger than the drag coefficient for the type of inlet with supersonic compression entirely inside, but the pressure recovery is larger for all flight conditions. The differences in drag can be eliminated for the design Mach number. Experimental results confirm the results of the theoretical analysis and show that pressure recoveries of 95 percent for Mach numbers of 1.33 and 1.52, 92 percent for a Mach number of 1.72, and 86 percent for a Mach number of 2.10 are possible, with the configurations considered. If the mass flow decreases, the total drag coefficient increases gradually and the pressure recovery does not change appreciably. The results of this work were first presented in a classified document issued in 1946.

DIFFUSERS, SUPERSONIC↗
NASA NTRS1953

Study of the supersonic propeller

In this paper a propeller having all sections operating at supersonic speeds is designated a supersonic propeller regardless of flight speed. Analyses assume subsonic flight speeds but very high rotational speeds. A very elementary analysis of the efficiency of a jet-propeller system is presented. A propeller analysis based on conventional vortex blade element theory is presented and reduced to a single point method which leads to an expression for optimum advance ratio in terms of hub-tip diameter ratio and airfoil fineness ratio. An expression for propeller efficiency in terms of advance ratio, hub-tip diameter ratio, and airfoil thickness ratio is also presented. Use is made of theoretical airfoil characteristics at supersonic speeds. A study of blade section interference, blade shock and expansion fields, at supersonic section speeds is presented. An example taken indicates that an efficiency of seventy percent can be obtained with a propeller having a tip Mach number of 2.3.

PROPELLERS, SUPERSONIC↗
NASA NTRS2018

Nozzle Plume/Shock Interaction Experimental and Computational Sonic Boom Analyses from the NASA Ames 9- by 7-Foot Supersonic Wind Tunnel

A wind tunnel test and a computational study were conducted to investigate the complex interactions between a supersonic nozzle plume and shock waves of differing strengths generated from various aft surfaces typical of supersonic aircraft. These analytically-defined aft surfaces were representative of horizontal tails of various sizes, and an aft deck. CFD simulations of many proposed model configurations allowed for assessments of the detailed flow interactions of components in close proximity to the nozzle, as well as assessments of the nozzle jet flow itself. The evaluation of the computational results for many candidate configurations guided the design of model components. The interactions of the waveforms from these surfaces with the jet exhaust plume can have significant adverse effects on the loudness of the sonic boom if the surfaces are not carefully integrated into an aircraft design. The greatest discrepancy in estimating sonic boom loudness for low-boom flight vehicles is currently in predicting the signatures from the aft part of an aircraft, including the interactions with the plume flow. The objectives of this test were to gain a better understanding of these interactions, and to provide a detailed experimental database from multiple sources for use as validation cases for CFD tool development. The subject test was run in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel in February 2016 at Mach numbers of 1.6 and 2.0, and was funded by the NASA Commercial Supersonics Technology (CST) Project. The nozzle flow was provided by high-pressure air (HPA) pumped through the model, and pressure signature data were acquired with the NASA 14-inch sonic boom pressure rail. The rail measured the locations of the shocks and expansions at various distances and off-track angles from the model. This enabled the impact of the nozzle plume/shock interactions on the near- and mid-field sonic boom pressure waveforms to be quantified. Schlieren images of the flow field around and behind the model were obtained with an RBOS (Retroreflective Background-Oriented Schlieren) technique to determine the origins of the shock and expansion waves, to identify the shape and boundaries of the plume, and to determine the changes in incoming and exiting waveforms within the plume. A total pressure rake was positioned closely behind the model nozzle in order to measure the total pressure profiles of the flow above, within, and below the nozzle exhaust. Model angles and positions in the tunnel were measured by photogrammetry using two cameras since the lack of a model force balance prevented the measurement of model deflections under load.Navier-Stokes computations using two different CFD codes were compared to the experimental sonic boom pressure signature data, and the rake total pressure data in the plume. A computational schlieren technique was used to compare the computed flow field with the RBOS images. The computational results were also used to complement the test data with flow field quantities that could not be measured, such as Mach number and pressure distributions to distinguish shock waves and expansion waves.

sonic boom↗
NASA NTRSDate not supplied

Assessment of Off-Design Low-Boom Characteristics of a Low-Boom Supersonic Transport

Most conceptual design methods for low-boom supersonic aircraft are developed for achieving an undertrack low-boom goal at the start of cruise. Although attempts have been made to design a supersonic aircraft achieving a low-boom goal for multiple azimuthal angles at the start of cruise, one unanswered question in inverse design optimization is how to define an achievable low-boom goal for multiple azimuthal angles. This paper proposes a new analysis method to assess off-design low-boom characteristics of a low-boom supersonic transport designed for an undertrack low-boom goal at the start of cruise. This method opens a potentially feasible path for conceptual design of a supersonic aircraft that has desired low-boom characteristics over the primary boom carpet for the entire cruise segment.

Low-boom supersonic transport↗
NASA NTRSDate not supplied

Assessment of Off-Design Low-Boom Characteristics of a Low-Boom Supersonic Transport

Most design methods for a low-boom supersonic aircraft were developed for achieving an undertrack low-boom goal at the start of cruise. Attempts were made to design a supersonic aircraft achieving a low-boom goal for multiple azimuthal angles at the start of cruise. One unanswered question is how to define an achievable low-boom goal for multiple azimuthal angles at the start of cruise. This paper proposes a new analysis method to assess off-design low-boom characteristics of a low-boom supersonic transport designed for an undertrack low-boom goal at the start of cruise. This method opens a potentially feasible path for designing a supersonic aircraft that has the desired low-boom characteristics over the primary boom carpet for the entire cruise segment.

Low-boom supersonic transport↗
NASA NTRS2024

Literature Review of Cumulative Noise Metrics Relevant to X-59 Supersonic Overflights

Upcoming studies with the X-59 aircraft will collect dose-response data to understand community response to en-route supersonic noise. This data collection effort will inform regulators in their efforts to potentially update the ban on commercial supersonic flight with acceptable noise standards. Part of the dataset will consist of end-of-day responses to the noise from multiple supersonic overflights. This document provides rationale from relevant literature surrounding which cumulative noise metric to pair with end-of-day survey responses for upcoming community studies with the X-59 aircraft. Despite its deficiencies, day-night average sound level (DNL) summation of candidate single-event metrics remains the most likely choice for a cumulative noise metric for multiple supersonic overflights because 1) it is widely used for other transportation noise sources and 2) its relevance for infrequent events is somewhat plausible, unlike some recent alternative metrics.

sonic boom↗
NASA NTRS1971

A generalized theory on the noise generation from supersonic shear layers.

A generalization is presented of Phillips' (1960) theory of noise generation by supersonic turbulent shear layers. Both Mach wave radiation and non-Mach wave noise radiation mechanisms are considered. The range of validity of Phillips' theory has been expanded to include the low supersonic and transonic ranges. These generalizations are important not only for their analytical rigor, but also for their prospective applications to practical problems in jet noise prediction and control. The noise generation mechanisms in a supersonic jet are found to differ from those in a subsonic jet. The theory is considered to offer some prospects of answering important questions in supersonic jet noise, such as noise source distribution, mean flow refraction effects, directivity, spectrum, and efficiency of noise radiation.

Pao, S. P.↗
NASA NTRS1973

Mixing-controlled supersonic combustion.

The technology of supersonic combustion and its practical significance for hypersonic flight are reviewed. It is shown that this technology makes possible a good qualitative and quantitative understanding of the physical phenomena related to the process of supersonic combustion. Some of the more important, summarized aspects of this technology include the physical description of the supersonic combustion flame, the chemical reaction rates and the diffusion process involved, the interaction between combustion and fluid dynamics, and the mathematical methods of supersonic combustion analysis.

Ferri, A.↗
NASA NTRS1973

A kernel function method for computing steady and oscillatory supersonic aerodynamics with interference.

The method presented uses a collocation technique with the nonplanar kernel function to solve supersonic lifting surface problems with and without interference. A set of pressure functions are developed based on conical flow theory solutions which account for discontinuities in the supersonic pressure distributions. These functions permit faster solution convergence than is possible with conventional supersonic pressure functions. An improper integral of a 3/2 power singularity along the Mach hyperbola of the nonplanar supersonic kernel function is described and treated. The method is compared with other theories and experiment for a variety of cases.

Cunningham, A. M., Jr.↗
NASA NTRS1974

Advanced supersonic propulsion study

A study was conducted to determine the promising propulsion systems for advanced supersonic transport application, and to identify the critical propulsion technology requirements. It is shown that noise constraints have a major effect on the selection of the various engine types and cycle parameters. Several promising advanced propulsion systems were identified which show the potential of achieving lower levels of sideline jet noise than the first generation supersonic transport systems. The non-afterburning turbojet engine, utilizing a very high level of jet suppression, shows the potential to achieve FAR 36 noise level. The duct-heating turbofan with a low level of jet suppression is the most attractive engine for noise levels from FAR 36 to FAR 36 minus 5 EPNdb, and some series/parallel variable cycle engines show the potential of achieving noise levels down to FAR 36 minus 10 EPNdb with moderate additional penalty. The study also shows that an advanced supersonic commercial transport would benefit appreciably from advanced propulsion technology. The critical propulsion technology needed for a viable supersonic propulsion system, and the required specific propulsion technology programs are outlined.

Sabatella, J. A.↗