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Jet Exit Test Facility

NASA Langley Research Center
The Langley Jet Exit Test Facility is an indoor engine/nozzle test stand that combines multiple-flow air propulsion simulation with high-pressure and high-mass-flow capabilities.
Test Section and Performance
 High-Pressure Air and
Cooling Capability
The Langley Jet Exit Test Facility (JETF) is an indoor engine/nozzle test stand which combines multiple-flow air propulsion simulation with high-pressure and high-mass-flow capabilities. Two individually controlled 1800-psiA air lines supply the test model system(s) and provide flow rates up to 23 lbm per sec. Supply air is heated to maintain room-temperature conditions at critical model measurement stations. The mass-flow rate of each air line is measured using a system of multiple critical venturi meters. Such systems allow accurate mass-flow computations over a large range of flow areas. Pressurized air from one or both supply lines is directed through a selected model interface system into the propulsion simulation geometry, and vented to atmosphere in the large test bay area. Exhaust flow is drawn outside the facility through two roof-mounted ventilation systems, keeping the test bay conditions at atmospheric pressure.

Two model support systems are available for testing. The dual-flow propulsion simulation system is designed for supply and control of two separate flow fields: a primary (core) flow and a secondary flow. It incorporates a 6-component strain-gage force-and-moment balance with maximum axial force capacity of 1200 lbf. A nozzle installed to this rig can be tested at charging-station total pressures up 350 psi and total temperatures up to 90 degrees F. Such conditions provide nozzle pressure ratios in excess of 20, simulating static conditions for supersonic flight. An alternate test rig, which does not incorporate a balance system, is a simple plenum chamber that mixes high-pressure air from both sources to supply a single intake for larger scale models. 		Two individually controlled 1800-psiA air lines supply the test model system(s) and provide flow rates up to 23 lbm per sec. Supply air is heated to maintain room-temperature conditions at critical model measurement stations. The mass-flow rate of each air line is measured using a system of multiple critical venturi meters. Such systems allow accurate mass-flow computations over a large range of flow areas, from less than 1 lbm/sec to over 20 lbm/sec. Pressurized air from one or both supply lines is directed through a selected model interface system into the propulsion simulation geometry, and vented to atmosphere in the large test bay area.

facility photograph
Static experimental investigation of counterflow thrust vectoring nozzle concept performed in JETF.
Model Observation
Both digital and standard photographs can be taken of the test area and model. Video monitoring of the model and test stand can also be recorded from several different view stations. Video of shadowgraph density-gradient imaging can also be recorded.
Instrumentation
Typical facility instrumentation consists of steady-state devices including a 6 -component strain-gauge balance, thermocouples, static pressure transducers and an electronically scanned pressure (ESP) system. Balance data are corrected for installation and momentum effects. The ESP system provides high-accuracy measurement (to 0.10%) of steady-state model pressures, utilizing standard modules with differential transducers which range from 5 psiD to 250 psiD. Additional independent static pressure transducers to larger ranges are also available. Dynamic pressure measurements have been included in past tests but are not part of the standard instrumentation base. 		Data Acquisition and Processing
The Unix-based data acquisition system can acquire up to 90 channels of analog data and several hundred ESP pressure measurements. An additional on-site UNIX workstation is used for post-acquisition processing, resulting in data transfer within minutes of run completion, if required. For customer support, the facility supplies a Windows PC with standard word-processing and spread-sheet software. Customer-supplied computers can be networked to the data reduction system as required. Secure data links and procedures are available for classified projects. 		Safety and Design Criteria
Langley's LHB 1710.15 Wind Tunnel Model System Criteria is the guideline for model design and fabrication. Model installation and any exceptions to this document must have the approval of the JETF Safety Head on a case-by-case basis to assure personnel and facility hardware are not exposed to risk.
Test Techniques
High-accuracy mass flow rate measurements are available from the Multiple Critical Venturi metering system on each air supply line. Available nonintrusive flow-visualization techniques include shadowgraph density-gradient imaging and surface-oil or paint-flow imaging.
Type of Testing
 Test Request Procedures

Test conducted in JETF. 		The Jet Exit Test Facility was originally designed for single-flow nozzle testing and played a significant role in the development of advanced aircraft thrust-vectoring propulsion nozzle concepts during the interval from 1970–1990. The facility was re-designed in the early 1990's to add the second independently controlled air-system. Typical test projects during the last decade include:

  • Performance evaluations of advanced multi-dimensional exhaust systems.
  • Calibration of nozzles and components for other applications (such as wind tunnel experiments).
  • Flow testing of full-scale fan-engine sectors for evaluation of new actuation-system concepts.
  • Performance testing of multiple-flow fluidic injection concepts (with core flow and two or more independently-controlled secondary flows) for thrust vectoring, plume control or throat-area control.
  • Application of suction as a secondary feature for thrust vectoring and performance augmentation.
  • High-volume dual-flow propulsion simulations such as ejector nozzles, and combined core and fan exhaust configurations with and without thrust reversing.
The first step of the test process is to submit a test request form. The form can be filled out electronically or printed for mailing at the NASA Langley aero Compass website. A posttest questionnaire is also available at this site. Our customers are encouraged to provide feedback to the facility for our continuous improvement process.

facility photograph

Document Version 1.0
Trademark Disclaimer:
The use of trademarks or names of manufacturers in this report is for accurate reporting and does not constitute an official endorsement, either expressed or implied, of such products or manufacturers by the National Aeronautics and Space Administration.
For more information contact:
The Jet Exit Test Facility Manager -- NASA Langley Research Center -- Hampton, Virginia 23681-2199
phone: 757-864-5948 | fax: 757-864-8195 | e-mail: wte+fm_jetexit@larc.nasa.gov
NASA Official Responsible For Content: Pete Jacobs
Page Curator: Lori Rowland
Date Last Updated: 07/01/08

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