Considerations of hot-gas ingestion for jet V/STOL aircraft
Hot gas ingestion problems for jet VTOL fighter aircraft with fuselage-mounted J85-GE-13 TURBOJET engine
VTOL AIRCRAFT↗
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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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Performance Calculations for a Boundary-Layer-Ingesting Fan Stage from Sparse Measurements
A test of the Boundary Layer Ingesting-Inlet / Distortion-Tolerant Fan was completed in NASA Glenn's 8-Foot by 6-Foot supersonic wind tunnel. Inlet and fan performance were measured by surveys using a set of rotating rake arrays upstream and downstream of the fan stage. Surveys were conducted along the 100 percent speed line and a constant exit corrected flow line passing through the aerodynamic design point. These surveys represented only a small fraction of the data collected during the test. For other operating points, data was recorded as snapshots without rotating the rakes which resulted in a sparser set of recorded data. This paper will discuss analysis of these additional, lower measurement density data points to expand our coverage of the fan map. Several techniques will be used to supplement the snapshot data at test conditions where survey data also exists. The supplemented snapshot data will be compared with survey results to assess the quality of the approach. Effective methods will be used to analyze the data set for which only snapshots exist.
fan efficiency↗
Aeromechanics Analysis of a Distortion-Tolerant Fan with Boundary Layer Ingestion
A propulsion system with Boundary Layer Ingestion (BLI) has the potential to significantly reduce aircraft engine fuel burn. But a critical challenge is to design a fan that can operate continuously with a persistent BLI distortion without aeromechanical failure -- flutter or high cycle fatigue due to forced response. High-fidelity computational aeromechanics analysis can be very valuable to support the design of a fan that has satisfactory aeromechanic characteristics and good aerodynamic performance and operability. Detailed aeromechanics analyses together with careful monitoring of the test article is necessary to avoid unexpected problems or failures during testing. In the present work, an aeromechanics analysis based on a three-dimensional, time-accurate, Reynolds-averaged Navier-Stokes computational fluid dynamics code is used to study the performance and aeromechanical characteristics of the fan in both circumferentially-uniform and circumferentially-varying distorted flows. Pre-test aeromechanics analyses are used to prepare for the wind tunnel test and comparisons are made with measured blade vibration data after the test. The analysis shows that the fan has low levels of aerodynamic damping at various operating conditions examined. In the test, the fan remained free of flutter except at one near-stall operating condition. Analysis could not be performed at this low mass flow rate operating condition since it fell beyond the limit of numerical stability of the analysis code. The measured resonant forced response at a specific low-response crossing indicated that the analysis under-predicted this response and work is in progress to understand possible sources of differences and to analyze other larger resonant responses. Follow-on work is also planned with a coupled inlet-fan aeromechanics analysis that will more accurately represent the interactions between the fan and BLI distortion.
Propulsion Aeroelasticity↗
A Review of Boundary Layer Ingestion Modeling Approaches for Use in Conceptual Design
The concept of boundary layer ingestion (BLI) has been proposed by NASA researchers and other groups for improving the performance of a number of future aircraft concepts. These future aircraft concepts include the STARC-ABL, D8 and N-3X among other examples. While BLI technology appears to be promising for improving the aircraft performance by reducing fuel burn, the benefits and challenges of using this technology are not well understood. As a result, there are a number of e orts ongoing within NASA which are attempting to model BLI and determine its overall bene t. Despite their common goal, there seems to be significant differences in the modeling approaches used in each e ort, with limited communication and collaboration between these groups. The purpose of this report is to document NASA's in-house BLI modeling e orts and their associated methodologies. Furthermore, the report will identify strengths and weaknesses of each methodology, specifically in regards to each method's application in conceptual design.
Boundary Layer Ingestion↗
Large-Scale Boundary Layer Ingesting Propulsor Research
NASA’s Advanced Air Transport Technology (AATT) project is investigating boundary layer ingesting (BLI) propulsors for advanced subsonic commercial vehicle concepts to enable the reduction of fuel burn. A multidisciplinary team of researchers from NASA, United Technologies Research Center (UTRC), Virginia Polytechnic University, and the Air Force Arnold Engineering Development Complex developed and tested an embedded BLI inlet and distortion-tolerant fan (BLI2DTF) system in the NASA Glenn Research Center (GRC) 8- foot by 6-foot (8x6) transonic wind tunnel. The test demonstrated the component performance goals necessary for an overall fuel burn reduction of 3 to 5 percent on a large hybrid wing body (HWB) aircraft. Special test equipment, including a raised floor with flow effectors and a bleed system, was developed for use in the 8x6 to produce the appropriate incoming boundary layer representative of an HWB application. Detailed measurements were made to determine the inlet total pressure loss and distortion, fan stage efficiency, and aeromechanic performance including blade vibration stress and displacement response. Results from this test were used as input to a vehicle-level system study performed by the AATT project to assess the impact of BLI on an alternative advanced concept aircraft referred to as the NASA D8 (ND8), which is somewhat similar to the HWB in its integration of the propulsor. This paper will provide an overview of the project timeline, special test equipment needed in the wind tunnel to develop the appropriate incoming boundary layer, and the difficulties in designing a propulsor for the test. The paper will conclude with some representative aerodynamic and aeromechanic data from the test itself and conclude with how this data was used in the ND8 system study.
Aerodynamic performance↗
Updated Assessment of Turboelectric Boundary Layer Ingestion Propulsion Applied to a Single-Aisle Commercial Transport
Recent advances in technology and a push for more environmentally friendly air transportation has led to interest in electrified aircraft propulsion (EAP). EAP encompasses many different propulsion system architectures which can also enable new, synergistic propulsion-airframe integration approaches. This report evaluates the combination of turboelectric EAP and fuselage boundary layer ingestion (BLI) propulsion in a concept called “STARC-ABL.” The predicted fuel consumption benefits of STARC-ABL are updated from a prior 2016 study with new mission requirements and analysis methodologies. Additionally, certification noise is added to the concept evaluation. To properly assess the impact of EAP, a new concept, “ST-ABL,” is developed for comparison which includes the fuselage BLI propulsor driven mechanically instead of by a turboelectric system. STARC-ABL is predicted to provide a 3.4% reduction in fuel consumption for a single-aisle class, 3500 nmi design mission and a 2.7% reduction for a 900 nmi mission, both relative to an advanced technology conventional aircraft. STARC-ABL is also predicted to have a Chapter 14 cumulative noise margin of 7 EPNdB. The non-EAP ST-ABL concept results in slightly higher fuel consumption and noise than STARC-ABL, indicating that the turboelectric system provides benefits over the mechanical drive approach to fuselage BLI. Areas for future research and evolution of the concept include assessing its applicability to other aircraft sizes, increasing the fidelity of BLI and electric component modeling, and investigating other EAP architecture options.
BLI↗
Performance Characteristics of a Boundary Layer Ingesting Inlet - Distortion Tolerant Fan Through CFD Code Coupling
A method of constructing a high-fidelity simulation using two NASA CFD codes, Launch Ascent and Vehicle Aerodynamics (LAVA), which is the general-purpose solver, and a turbomachinery specific code NASA-TURBO (TURBO), will be presented. Validation of the code coupling is performed through comparison to experimental data obtained in the 2017 wind tunnel test of NASA’s Boundary Layer Ingesting Inlet - Distortion Tolerant Fan (BLI2DTF). For the simulation, the external flow field is computed by LAVA utilizing a steady-state Reynolds-averaged Navier-Stokes (RANS) methodology. Data from LAVA is exchanged with TURBO, which simulated the propulsor utilizing an unsteady-RANS methodology. A sensitivity analysis is performed using averaged and instantaneous data transfer between the two codes, as well as varying the amount of simulation time TURBO computes between updates. The results of the coupled simulations appear to replicate the BLI2DTF experiment correctly. Static pressure taps leading into and around the nacelle, total pressure ratio and efficiency of the propulsor, and profiles of total temperature, pressure, and Mach number at the rear measurement plane, aft of the propulsor, are in good agreement with experimental data. These results provide confidence that the coupled simulation is behaving in a physically realizable manner.
CFD↗
Experimental Investigation of a Boundary Layer Ingesting Tailcone Thruster Configuration at the National Transonic Facility
A transonic, high Reynolds number wind tunnel test of a Boundary Layer Ingesting Tailcone System (BLITS) was conducted in the National Transonic Facility (NTF) at the NASA Langley Research Center during the spring of 2023. The test was sponsored by the NASA Advanced Air Transport Technology Project and produced a large dataset to help in the development and validation of an integrated airframe-turbomachinery computational simulation capability. The Common Research Model with Tail Cone Thruster (CRM-TCT) configuration was tested at Mach numbers from 0.75 to 0.85 and Reynolds number based on mean aerodynamic chord from 5 to 15 million, with the objective of characterizing the tailcone nacelle inlet pressure and flow angle profile, characterizing the aftbody boundary layer (BL), and evaluating the overall airframe configuration performance. The test article included multiple tailcone nacelle assemblies with different measurement objectives, and each assembly was able to be controlled remotely and rotate in small increments, allowing for an increased measurement density for characterizing the nacelle inlet distortion. Additionally, the use of cryogenic-rated miniature BL rakes was successful in measuring boundary layer heights on the aftbody. Sensitivities of the measured quantities of interest to Mach number, Reynolds number, angle of attack, and nacelle weight flow rate are also presented.
boundary layer ingestion (BLI)↗
Experimental Investigation of a Boundary Layer Ingesting Tailcone Thruster Configuration at the National Transonic Facility
A transonic, high Reynolds number wind tunnel test of a Boundary Layer Ingesting Tailcone System (BLITS) was conducted in the National Transonic Facility (NTF) at the NASA Langley Research Center during the spring of 2023. The test was sponsored by the NASA Advanced Air Transport Technology Project and produced a large dataset to help in the development and validation of an integrated airframe-turbomachinery computational simulation capability. The Common Research Model with Tail Cone Thruster (CRM-TCT) configuration was tested at Mach numbers from 0.75 to 0.85 and Reynolds number based on mean aerodynamic chord from 5 to 15 million, with the objective of characterizing the tailcone nacelle inlet pressure and flow angle profile, characterizing the aftbody boundary layer (BL), and evaluating the overall airframe configuration performance. The test article included multiple tailcone nacelle assemblies with different measurement objectives, and each assembly was able to be controlled remotely and rotate in small increments, allowing for an increased measurement density for characterizing the nacelle inlet distortion. Additionally, the use of cryogenic-rated miniature BL rakes was successful in measuring boundary layer heights on the aftbody. Sensitivities of the measured quantities of interest to Mach number, Reynolds number, angle of attack, and nacelle weight flow rate are also presented.
boundary layer ingestion (BLI)↗
24-hour human urine and serum profiles of Bisphenol A following ingestion in soup: Individual pharmacokinetic data and emographics
Here we present data to evaluate potential absorption of Bisphenol A through non-metabolizing tissues of the upper digestive tract. Concurrent serum and urine concentrations of d6-BPA, and its glucuronide and sulfate conjugates, were measured over a 24 h period in 10 adult male volunteers following ingestion of 30 μg d6-BPA/kg body weight in soup. The pharmacokinetic behavior of BPA and its metabolites in this cohort (rapid absorption, complete elimination, evidence against sublingual absorption) was reported. This Data in Brief article contains the corresponding individual pharmacokinetic data, reports the demographics of the cohort and provides additional details related to the analytical methods employed and is related to [4].
59 BASIC BIOLOGICAL SCIENCES↗
THREE-DIMENSIONAL HYDRODYNAMICAL SIMULATIONS OF A PROTON INGESTION EPISODE IN A LOW-METALLICITY ASYMPTOTIC GIANT BRANCH STAR
We use the three-dimensional (3D) stellar structure code DJEHUTY to model the ingestion of protons into the intershell convection zone of a 1 M{sub Sun} asymptotic giant branch star of metallicity Z = 10{sup -4}. We have run two simulations: a low-resolution one of around 300,000 zones and a high-resolution one consisting of 2,000,000 zones. Both simulations have been evolved for about 4 hr of stellar time. We observe the existence of fast, downward flowing plumes that are able to transport hydrogen into close proximity to the helium-burning shell before burning takes place. The intershell in the 3D model is richer in protons than the 1D model by several orders of magnitude and so we obtain substantially higher hydrogen-burning luminosities-over 10{sup 8} L{sub Sun} in the high-resolution simulation-than are found in the 1D model. Convective velocities in these simulations are over ten times greater than the predictions of mixing length theory, though the 3D simulations have greater energy generation due to the enhanced hydrogen burning. We find no evidence of the convective zone splitting into two, though this could be as a result of insufficient spatial resolution or because the models have not been evolved for long enough. We suggest that the 1D mixing length theory and particularly the use of a diffusion algorithm for mixing do not give an accurate picture of these events. An advective mixing scheme may give a better representation of the transport processes seen in the 3D models.
79 ASTRONOMY AND ASTROPHYSICS↗
GLOBAL NON-SPHERICAL OSCILLATIONS IN THREE-DIMENSIONAL 4π SIMULATIONS OF THE H-INGESTION FLASH
We performed three-dimensional simulations of proton-rich material entrainment into {sup 12}C-rich He-shell flash convection and the subsequent H-ingestion flash that took place in the post-asymptotic giant branch star Sakurai's object. Observations of the transient nature and anomalous abundance features are available to validate our method and assumptions, with the aim of applying them to very low-metallicity stars in the future. We include nuclear energy feedback from H burning and cover the full 4π geometry of the shell. Runs on 768{sup 3} and 1536{sup 3} grids agree well with each other and have been followed for 1500 minutes and 1200 minutes. After an 850 minute long quiescent entrainment phase, the simulations enter into a global non-spherical oscillation that is launched and sustained by individual ignition events of H-rich fluid pockets. Fast circumferential flows collide at the antipode and cause the formation and localized ignition of the next H-overabundant pocket. The cycle repeats for more than a dozen times while its amplitude decreases. During the global oscillation, the entrainment rate increases temporarily by a factor of ≈100. Entrained entropy quenches convective motions in the upper layer until the burning of entrained H establishes a separate convection zone. The lower-resolution run hints at the possibility that another global oscillation, perhaps even more violent, will follow. The location of the H-burning convection zone agrees with a one-dimensional model in which the mixing efficiency is calibrated to reproduce the light curve. The simulations have been performed at the NSF Blue Waters supercomputer at NCSA.
79 ASTRONOMY AND ASTROPHYSICS↗
Turbo FRMAC Implementation of IAEA Radiological Assessment Methodologies for Nuclear and Radiological Emergencies: Ingestion Pathway and Skin and Thyroid Monitoring
This report documents the findings of an assessment of the Turbo FRMAC© software’s ability to implement International Atomic Energy Agency (IAEA) guidance for calculating operational intervention levels (OIL) for nuclear and radiological emergencies. This assessment is a continuation of previous work that considered IAEA OIL1 and OIL2 for evacuation and relocation protective actions. The IAEA OIL and U.S. Federal Radiological Monitoring and Assessment Center (FRMAC) derived response and intervention level methodologies were compared for ingestion and skin and thyroid monitoring pathways. This comparison revealed significant differences in IAEA versus FRMAC handling of these pathways, which precluded an assessment of Turbo FRMAC’s ability to implement the IAEA approach.
61 RADIATION PROTECTION AND DOSIMETRY↗
Opportunities for Improvement in FRMAC's Assessment Method for Ingestion of Contaminated Crops
This report provides recommendations to improve the assessment method of the Federal Radiological Monitoring and Assessment Center (FRMAC) for the ingestion of crops contaminated with radionuclides. The current FRMAC method of calculating investigation levels (ILs) and crop derived response levels (DRLs) is detailed. Recommended modifications to these calculations are presented based on the following aspects: handling radionuclide mixtures, no immediate equilibrium, washing of contaminated crops, and updated dietary intake rates.
54 ENVIRONMENTAL SCIENCES↗
Convective inertia and gas ingestion effects on flow regimes of the viscoseal - Theory and experiment.
Viscoseal operation in superlaminar flow regime noting pressure patterns, end effect, gas ingestion and sealing capacity
TURBULENT FLOW↗
Experimental investigation of vapor ingestion in the Centaur liquid hydrogen tank
Vapor ingestion during liquid outflow in scale model Centaur liquid hydrogen tank
Lacovic, R. F.↗
Convective Inertia and Gas Ingestion Effects on Flow Regimes of the Viscoseal Theory and Experiment
Theoretical and experimental study of convective inertia and gas ingestion effects on flow regimes of viscoseal
Johnson, R. L.↗