Search NASA⌕ Search

SEARCH · Search NASA

Results for “Inlets”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Research on Supersonic Inlet Bleed

Phase I data results of the Fundamental Inlet Bleed Experiments project at NASA Glenn Research Center (GRC) are presented which include flow coefficient results for two single-hole boundary-layer bleed configurations. The bleed configurations tested are round holes at inclination angles of 90deg and 20deg both having length-to-diameter ratios of 2.0. Results were obtained at freestream Mach numbers of 1.33, 1.62, 1.98, 2.46, and 2.92 and unit Reynolds numbers of 0.984, 1.89, and 2.46 10(exp 7)/m. Approach boundary-layer data are presented for each flow condition and the flow coefficient results are compared to existing multi-hole data obtained under similar conditions. For the 90deg hole, the single and multi-hole distributions agree fairly well with the exception that under supercritical operation, the multi-hole data chokes at higher flow coefficient levels. This behavior is also observed for the 20deg hole but to a lesser extent. The 20deg hole also shows a markedly different characteristic at subcritical operation. Also presented are preliminary results of a Computational Fluid Dynamics (CFD) analysis of both configurations at the Mach 1.33 and a unit Reynolds number of 2.46 10(exp 7)/m. Comparison of the results shows the agreement to be very good.

Davis, David O.↗
NASA NTRS2013

The NTF Inlet Guide Vanes Thermal Gradient Problem and Its Mitigation

The National Transonic Facility (NTF) utilizes Inlet Guide Vanes (IGV) to provide precise, quick response Mach number control for the tunnel. During cryogenic operations, the massive IGV structure can experience large thermal gradients, measured as "Delta T or (Delta)T", between the IGV ring and its support structure called the transfer case. If these temperature gradients are too large, the IGV structure can be stressed beyond its safety limit and cease operation. In recent years, (Delta)T readings exceeding the prescribed safety limits were observed frequently during cryogenic operations, particularly during model access. The tactical operation methods of the tunnel to minimize (Delta)T did not always succeed. One obvious option to remedy this condition is to warm up the IGV structure by disabling the main drive operation, but this "natural" warm up method can takes days in some cases, resulting in productivity loss. This paper documents the thermal gradient problem associated with the IGV structure during cryogenic operation and how the facility has recently achieved an acceptable mitigation which has resulted in improved efficiency of operations.

Venkat, Venki S.↗
NASA NTRS2013

Aerodynamic Measurements of a Variable-Speed Power-Turbine Blade Section in a Transonic Turbine Cascade at Low Inlet Turbulence

Aerodynamic measurements obtained in a transonic linear cascade were used to assess the impact of large incidence angle and Reynolds number variations on the 3-D flow field and midspan loss and turning of a 2-D section of a variable-speed power-turbine (VSPT) rotor blade. Steady-state data were obtained for ten incidence angles ranging from +15.8 deg to −51.0 deg. At each angle, data were acquired at five flow conditions with the exit Reynolds number (based on axial chord) varying over an order-of-magnitude from 2.12×10(exp 5) to 2.12×10(exp 6). Data were obtained at the design exit Mach number of 0.72 and at a reduced exit Mach number of 0.35 as required to achieve the lowest Reynolds number. Midspan total-pressure and exit flow angle data were acquired using a five-hole pitch/yaw probe surveyed on a plane located 7.0 percent axial chord downstream of the blade trailing edge plane. The survey spanned three blade passages. Additionally, three-dimensional half-span flow fields were examined with additional probe survey data acquired at 26 span locations for two key incidence angles of +5.8 deg and −36.7 deg. Survey data near the endwall were acquired with a three-hole boundary-layer probe. The data were integrated to determine average exit total-pressure and flow angle as functions of incidence and flow conditions. The data set also includes blade static pressures measured on four spanwise planes and endwall static pressures. Tests were conducted in the NASA Glenn Transonic Turbine Blade Cascade Facility. The measurements reflect strong secondary flows associated with the high aerodynamic loading levels at large positive incidence angles and an increase in loss levels with decreasing Reynolds number. The secondary flows decrease with negative incidence as the blade becomes unloaded. Transitional flow is admitted in this low inlet turbulence dataset, making it a challenging CFD test case. The dataset will be used to advance understanding of the aerodynamic challenges associated with maintaining efficient power turbine operation over a wide shaft-speed range. deg

Flegel-McVetta, Ashlie B.↗
NASA NTRS2016

Experimental Evaluation of Inlet Distortion on an Ejector Powered Hybrid Wing Body at Take-off and Landing Conditions

As part of the NASA Environmentally Responsible Aircraft project, an ultra high bypass ratio engine integration on a hybrid wing body demonstration was planned. The goal was to include engine and airframe integration concepts that reduced fuel consumption by at least 50% while still reducing noise 42 db cumulative on the ground. Since the engines would be mounted on the upper surface of the aft body of the aircraft, the inlets may be susceptible to vortex ingestion from the wing leading edge at high angles of attack and sideslip, and separated wing/body flow. Consequently, experimental and computational studies were conducted to collect flow surveys useful for characterizing engine operability. The wind tunnel tests were conducted at two NASA facilities, the 14- by 22-foot at NASA Langley and the 40- by 80-foot at NASA Ames Research Center. The test results included in this paper show that the distortion and pressure recovery levels were acceptable for engine operability. The CFD studies conducted to compare to experimental data showed excellent agreement for the angle of attacks examined, although failed to match the low speed experimental data at high sideslip angles.

Carter, Melissa B.↗
NASA NTRS2017

Multipurpose Rotating Rake Arrays for Integrated Inlet and Fan Stage Performance Measurement

Low-pressure-ratio fan stage performance measurement requires precise measurement of conditions upstream and downstream of the fan stage. This presentation will discuss the rotating rake arrays used for the recent Boundary Layer Ingesting Inlet-Distortion-Tolerant Fan experiment in the NASA Glenn 8 by 6 foot wind tunnel. To achieve precise measurements, simulations of the rake sampling from pre-test CFD (Computerized Fluid Dynamics) solutions were used to optimize the number and locations of rake instruments.

performanc↗
NASA NTRS2018

Laser Displacement Measurements of Fan Blades in Resonance and Flutter During the Boundary Layer Ingesting Inlet and Distortion-Tolerant Fan Test

NASA's Advanced Air Transport Technology Project is investigating boundary layer ingesting propulsors for future subsonic commercial aircraft to improve aircraft efficiency, thereby reducing fuel burn. To that end, a boundary layer ingesting inlet and distortion-tolerant fan stage was designed, fabricated, and tested within the 8' x 6' Supersonic Wind Tunnel at NASA Glenn Research Center. Because of the distortion in the air flow over the fan, the blades were designed to withstand a much higher aerodynamic forcing than for a typical clean flow. The blade response for several resonance modes were measured during start-up and shutdown, as well as at near 85% design speed. Flutter in the first bending mode was also observed in the fan at the design speed, at an off-design condition, although instabilities were difficult to instigate with this fan in general. Blade vibrations were monitored through twelve laser displacement probes that were placed around the inner circumference of the casing, at the blade leading and trailing edges. These probes captured the movement of all the blades during the entire test. Results are presented for various resonance mode amplitudes, frequencies and damping, as well as flutter amplitudes and frequency. Benefits and disadvantages of laser displacement probe measurements versus strain gage measurements are discussed.

NSMS↗
NASA NTRS2018

W-8 Inlet In-Duct Array Evaluation

An overview is provided of an evaluation of the data quality for inlet in-duct array measurements in the W-8 Single Stage Axial Compressor Facility with measurements of a rotor alone configuration.

aeroacoustic↗
NASA NTRS2018

Data Analysis Techniques for Fan Performance in Highly-Distorted Flows from Boundary Layer Ingesting Inlets

The design of a unique distortion-tolerant fan for a high-bypass ratio boundary-layer ingesting propulsion system has been completed and a rig constructed and tested in the NASA Glenn 8’x6’ wind tunnel. Processing the data from the experiment presented some interesting challenges because of the complexity of the experimental setup and the flow through the test rig. The experiment was run in three phases, each of which employed a unique complement of inlet throat and fan face instrumentation to avoid the blockage that would have resulted from simultaneously installing all of the rakes. The measurement from the individual test points were subsequently combined to compute the overall stage performance. A CFD model of the experiment was used to gain understanding of the flow field and to test some of the techniques proposed for interpolating and extrapolating the measurements into regions where measurements were not made. This capability became extremely useful when it was discovered that there was an unexpected total temperature distortion in the tunnel. The CFD model was modified by inserting a total temperature profile at the upstream boundary that mimicked the measured distortion where measurements were available and that CFD solution was used to investigate methods to infer the complete total temperature field at the fan face.

Hardin, Larry W.↗
NASA NTRS2018

Aerodynamic Shape Optimization of the STARC-ABL Concept for Minimal Inlet Distortion

The NASA single-aisle turboelectric aircraft with an aft boundary layer propulsor (STARC-ABL) concept utilizes a novel electrically driven aft fan that ingests the fuselage boundary-layer for increased propulsive efficiency. In this paper we examine how aerodynamic shaping of the fuselage diffuser and nacelle inlet can reduce the flow distortion at the aft fan. Adjoint-based aerodynamic shape optimization with the ARP1420 distortion metric objective is used to automatically determine the optimal shapes for minimal fan-face distortion. Single and multipoint optimizations are carried out for simplified body-duct and wing-body-duct configurations. These two configurations highlight the importance of including the wing downwash effects when designing the propulsor. The optimizations showed the body-duct configuration can obtain cruise distortion values of approximately 1% while the wing-body-duct configuration can obtain distortion values of just over 2%.

Kenway, Gaetan K. W.↗
NASA NTRS2021

Combined Cycle Engine Large-Scale Inlet for Mode Transition Studies: System Identification Rack Software Design

This report describes the development of the system identification (SysID) rack custom application code. This code is used to automate the system identification experimental processes for the National Aeronautics and Space Administration (NASA) Combined Cycle Engine Large-Scale Inlet for Mode Transition Experiments testbed. This series of experiments took place in the NASA Glenn Research Center (GRC) 10 foot by 10 foot (10x10) Supersonic Wind Tunnel (SWT) test facility. The SysID code was developed to apply command signals to testbed actuators, receive actuator feedback signals, and acquire sensor data which is used to identify the dynamics of the experimental processes. This code development and the process identification experiments were conducted during Phase-2 testing at various operating points. These points were predefined from data collected during the Phase-1 testbed characterization experiments. The developed SysID code was executed on a NASA designed and built real-time data acquisition (DAQ) and controls (SysID) rack. This report focuses on the development of the SysID rack real-time DAQ and control hardware and the custom application code used to automate the system identification process. The implementation of this reliable and efficient data acquisition and controls development tool is demonstrated by presenting an example of experimental data collected to be used for system identification.

R Thomas↗
NASA NTRSDate not supplied

Four Bed Carbon Dioxide Scrubber Engineering Development Unit Cabin Air Inlet Testing

This paper reviews a test series conducted on the Four Bed Carbon Dioxide Scrubber Engineering Development Unit, a ground test analog for the Four Bed Carbon Dioxide Scrubber Technology Demonstration currently operating on the International Space Station. For this test series conducted in mid-2022, an alternate FBCO2 inlet air location (direct from the cabin) was evaluated. This paper presents test results, rationale for observed performance changes, and possible ramifications for the flight FBCO2 Scrubber.

Life Support↗
NASA NTRSDate not supplied

Four Bed Carbon Dioxide Scrubber Engineering Development Unit Cabin Air Inlet Testing

This paper reviews a test series conducted on the Four Bed Carbon Dioxide Scrubber Engineering Development Unit, a ground test analog for the Four Bed Carbon Dioxide Scrubber Technology Demonstration currently operating on the International Space Station. For this test series conducted in mid-2022, an alternate FBCO2 inlet air location (direct from the cabin) was evaluated. This paper presents test results, rationale for observed performance changes, and possible ramifications for the flight FBCO2 Scrubber.

Life Support↗
NASA NTRSDate not supplied

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↗
NASA NTRSDate not supplied

Comparison of Inlet Broadband Acoustic Liner Predictions to Quiet Technology Demonstrator 3 Flight Data

Companion acoustic liner attenuation predictions and flight data representative of certification conditions are analyzed to determine the validation quality and gain an understanding of current prediction shortcomings. These comparisons are limited to the inlet broadband component of fan noise. Two prediction methods are assessed: a traditional, semiempirical model, and a computational approach with a parabolic duct propagation code coupled with a Ffowcs Williams-Hawkings solver for free-field propagation. The semiempirical method is widely used for aircraft system noise predictions, but does not explicitly account for several physical parameters important for sound attenuation. The computational approach includes these effects, but requires a significant increase in cycle time. For the three-degree-of-freedom (3DOF) liner tested, both methods have a bias error less than 0.5 dB for cutback and takeoff power settings, and a much larger 3–4 dB bias for approach power setting. The standard deviation of each method varies between 1–2 dB for different conditions. The similar performance of both approaches illustrates that, in this instance, the additional complexity of the computational approach does not provide a clear improvement over the semiempirical method. Planned improvements to the numerical grid and source assumptions may result in reevaluation of this conclusion in later work.

aircraft system noise↗
DOE OSTI2019

OSU High Temperature Test Facility Test Acceptance Report, PG-29 Low Power (<350kW) Double Ended Inlet-Outlet Crossover Duct Break, Hybrid Heater

Test Acceptance Report for Test PG-29 at the Oregon State University High Temperature Test Facility. The purpose of this test is to examine the progression of the Double Ended Inlet-Outlet Crossover Duct Break transient in an integral test facility scaled to General Atomics’ Modular High Temperature Gas Reactor (MHTGR) design.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2022

Multi-channel pulsed valve inlet system and method

A multichannel inlet system for a mass spectrometer includes a plurality of valve assemblies coupled to a manifold, and a pulsed valve driver. The manifold is configured to be connected in fluid connection with an ion trap of the mass spectrometer. Each valve assembly includes a valve and an injection port operably coupled to receive the reagent. The valve has an actuated state in which the valve provides fluid communication between the injection port and the manifold, and an unactuated state in which the valve substantially prevents fluid communication between the injection port and the manifold. The pulsed valve driver is operably connected to receive a pulse signal sequence from a processor, and is configured to generate pulsed valve drive signals for one or more of the valves based on the pulse signal sequence to cause a corresponding one of the valves to be in the actuated state.

Kenttamaa, Hilkka↗