Design Modifications of a Supersonic Wind Tunnel for High Speed Mixing Research of a Novel Injector in a Scramjet Combustor

2015 ◽  
Author(s):  
Leslie A. Smith ◽  
Saeed Farokhi
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Supersonic Wind Tunnel ◽  
Scramjet Combustor

Multi-Angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber Based Endoscopes

2015 ◽  
Author(s):  
Lin Ma ◽  
Andrew J. Wickersham ◽  
Wenjiang Xu ◽  
Scott J. Peltier ◽  
Timothy M. Ombrello ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Thermal Management ◽  
High Speed ◽  
Flow Structures ◽  
Data Sets ◽  
Propulsion Systems ◽  
Supersonic Wind Tunnel ◽  
Optical Access ◽  
Equipment Cost ◽  
Pod Analysis

This paper reports new measurements and analysis made in the Research Cell 19 supersonic wind-tunnel facility housed at the Air Force Research Laboratory. The measurements include planar chemiluminescence from multiple angular positions obtained using fiber based endoscopes (FBEs) and the accompanying velocity fields obtained using particle image velocimetry (PIV). The measurements capture the flame dynamics from different angles (e.g., the top and both sides) simultaneously. The analysis of such data by proper orthogonal decomposition (POD) will also be reported. Non-intrusive and full-field imaging measurements provide a wealth of information for model validation and design optimization of propulsion systems. However, it is challenging to obtain such measurements due to various implementation difficulties such as optical access, thermal management, and equipment cost. This work therefore explores the application of FBEs for non-intrusive imaging measurements in supersonic propulsion systems. The FBEs used in this work are demonstrated to overcome many of the practical difficulties and significantly facilitate the measurements. The FBEs are bendable and have relatively small footprints (compared to high-speed cameras), which facilitates line-of-sight optical access. Also, the FBEs can tolerate higher temperatures than high-speed cameras, ameliorating the thermal management issues. Lastly, the FBEs, after customization, can enable the capture of multiple images (e.g., images of the flowfields at multi-angles) onto the same camera chip, greatly reducing the equipment cost of the measurements. The multi-angle data sets, enabled by the FBEs as discussed above, were analyzed by POD to extract the dominating flame modes when examined from various angular positions. Similar analysis was performed on the accompanying PIV data to examine the corresponding modes of the flowfields. The POD analysis provides a quantitative measure of the dominating spatial modes of the flame and flow structures and is an effective mathematical tool to extract key physics from large data sets such as the high-speed measurements collected in this study. However, past POD analysis has been limited to data obtained from one orientation only. The availability of data at multiple angles in this study is expected to provide further insights into the flame and flow structures in high-speed propulsion systems.

The Effect of Pulsed Injection on Supersonic Shear Layer Mixing in a Scramjet Combustor

2018 ◽  
Vol 35 (3) ◽  
pp. 203-215
Author(s):  
Leslie Smith ◽  
Saeed Farokhi
Keyword(s):  
Wind Tunnel ◽  
Shear Layer ◽  
Test Section ◽  
Pulse Width ◽  
Static Pressure ◽  
Experimental Studies ◽  
Lower Wall ◽  
Supersonic Wind Tunnel ◽  
Scramjet Combustor ◽  
Secondary Injection

Abstract A novel injector has been designed and cold flow injection tests were performed in a modified supersonic wind tunnel. To complement these experimental studies three dimensional STAR-CCM+CFD simulations were developed. The pulse width may be varied, with options of injecting gas for 33 %, 50 % and 66 % of the injection period. The scramjet combustor environment is simulated in a supersonic wind tunnel through a backward facing step for secondary injection purposes and a 157.5 cm (62-inch) long test section. The gas in secondary injection is carbon dioxide and the primary flow is air. The simulations show a coupled interaction between the forcing from injection and the shear layer. Steady state static pressure measurements on the lower wall of the wind tunnel test section agree well with the simulated static pressure along the lower wall. The pulse width strongly impacts shear layer reattachment on the lower wall and varies between 2.4 and 4.3 step heights. Reduction in duty cycle from 66 % to 33 % at 1 kHz caused ~30 % reduction in the shear layer reattachments distance, which points to large scale mixing enhancement.

Low-Turbulence High-Speed Wind Tunnel for the Determination of Cascade Shock Losses

1979 ◽  
Author(s):  
J. A. Slovisky ◽  
W. B. Roberts ◽  
D. M. Sandercock
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Supersonic Wind Tunnel ◽  
Smoke Flow ◽  
Contraction Ratio ◽  
Curved Shock Waves ◽  
Visualization Techniques

A low turbulence high-speed wind tunnel, using anti-turbulence screening and a 100:1 contraction ratio, has been found suitable for high-speed smoke flow visualization. The location and strength of normal, oblique, and curved shock waves generated by transonic or supersonic wind tunnel flow over airfoils or through axial compressor cascades is determined by combined shadowgraph and smokelines visualization techniques without the interference effects caused by intrusive probes. The Reynolds number based on chord varied between 50,000 and 106. Preliminary results are compared with the relevant theory and data gathered using a total pressure probe.

Multi-angular Flame Measurements and Analysis in a Supersonic Wind Tunnel Using Fiber-Based Endoscopes

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Lin Ma ◽  
Andrew J. Wickersham ◽  
Wenjiang Xu ◽  
Scott J. Peltier ◽  
Timothy M. Ombrello ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Thermal Management ◽  
High Speed ◽  
Flow Fields ◽  
Flow Structures ◽  
Data Sets ◽  
Propulsion Systems ◽  
Supersonic Wind Tunnel ◽  
Equipment Cost ◽  
Pod Analysis

This paper reports new measurements and analysis made in the Research Cell 19 supersonic wind-tunnel facility housed at the Air Force Research Laboratory. The measurements include planar chemiluminescence from multiple angular positions obtained using fiber-based endoscopes (FBEs) and the accompanying velocity fields obtained using particle image velocimetry (PIV). The measurements capture the flame dynamics from different angles (e.g., the top and both sides) simultaneously. The analysis of such data by proper orthogonal decomposition (POD) will also be reported. Nonintrusive and full-field imaging measurements provide a wealth of information for model validation and design optimization of propulsion systems. However, it is challenging to obtain such measurements due to various implementation difficulties such as optical access, thermal management, and equipment cost. This work therefore explores the application of the FBEs for nonintrusive imaging measurements in the supersonic propulsion systems. The FBEs used in this work are demonstrated to overcome many of the practical difficulties and significantly facilitate the measurements. The FBEs are bendable and have relatively small footprints (compared to high-speed cameras), which facilitates line-of-sight optical access. Also, the FBEs can tolerate higher temperatures than high-speed cameras, ameliorating the thermal management issues. Finally, the FBEs, after customization, can enable the capture of multiple images (e.g., images of the flow fields at multi-angles) onto the same camera chip, greatly reducing the equipment cost of the measurements. The multi-angle data sets, enabled by the FBEs as discussed above, were analyzed by POD to extract the dominating flame modes when examined from various angular positions. Similar analysis was performed on the accompanying PIV data to examine the corresponding modes of the flow fields. The POD analysis provides a quantitative measure of the dominating spatial modes of the flame and flow structures, and is an effective mathematical tool to extract key physics from large data sets as the high-speed measurements collected in this study. However, the past POD analysis has been limited to data obtained from one orientation only. The availability of data at multiple angles in this study is expected to provide further insights into the flame and flow structures in high-speed propulsion systems.

Videogrammetry of the Model’s Attitude in Wind Tunnel Testing

2012 ◽  
Vol 190-191 ◽  
pp. 1273-1277 ◽  
Author(s):  
Zheng Yu Zhang ◽  
Zhong Xiang Sun ◽  
Xu Hui Huang ◽  
Yan Sun
Keyword(s):  
Standard Deviation ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Systematic Error ◽  
Measurement System ◽  
High Speed ◽  
Wind Tunnel Test ◽  
Wind Tunnel Testing ◽  
Supersonic Wind Tunnel ◽  
Tunnel Testing

The advanced precision of drag coefficient is 0.0001 for the high speed wind tunnel test of measuring forces, the model’s angle of attack precision is ≤0.01°following errors distribution. A videogrammetric method of model’s attitude is therefore proposed, its uncertainty is investigated, and a compensation method of its systematic error is also presented by this paper. The three engineering videogrammetric experiments of attack angle in 2 meter supersonic wind tunnel testing have demonstrated that measuring standard deviation of videogrammetric measurement system established by this paper is ≤0.0094°, in addition it neither destroys the model’s shape, nor changes the stiffness or strength, so it is useful and effective.

Preliminary Tests of High Speed PIV Measurements in a Ludwieg-Tube Supersonic Wind Tunnel

2007 ◽  
Author(s):  
Khalid Juhany ◽  
A. Darji ◽  
Mohammed Zahrani ◽  
Husam Husieni ◽  
Majed Behairi ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Supersonic Wind Tunnel ◽  
Piv Measurements ◽  
Ludwieg Tube

The Ludwieg Pressure-Tube Supersonic Wind Tunnel

1963 ◽  
Vol 14 (2) ◽  
pp. 143-157 ◽  
Author(s):  
A. J. Cable ◽  
R. N. Cox
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Nozzle Exit ◽  
High Speed ◽  
Layer Growth ◽  
Stagnation Pressure ◽  
Pressure Tube ◽  
Rarefaction Waves ◽  
Supersonic Wind Tunnel ◽  
Blow Down

SummaryA description is given of a supersonic pressure-tube wind tunnel which has been constructed at A.R.D.E. This is a blow-down tunnel which uses as a reservoir a long tube filled with gas under pressure. A quasi-steady supersonic flow is achieved by expanding in a convergent-divergent nozzle the subsonic flow behind rarefaction waves which propagate down the tube when a diaphragm at the nozzle exit is burst. The theory of the operation of the tunnel is given and calculations are made of the boundary-layer growth along the tube. Pressure-time records were obtained in the tube, and a high speed camera was used to obtain pictures of the flow round a model. Measurements also included a pitot-tube traverse of the nozzle exit, and the Mach number distribution was determined from the ratio of the pitot to the stagnation pressure. Tests showed that, as predicted, a constant stagnation pressure was obtained ahead of the nozzle, and it is considered that a tunnel of this type would be a cheap and simple way of obtaining an intermittent tunnel with adequate running time for many types of test, and capable of operating at a Reynolds number of more than 107 per inch at a Mach number of about 3·5.

scholarly journals Design, Construction and Testing of a Desktop Supersonic Wind Tunnel

2005 ◽  
Vol 4 (2) ◽  
Author(s):  
Vi Rapp ◽  
Jennifer Jacobsen ◽  
Mark Lawson ◽  
Andrew Parker ◽  
Kuan Chen
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Compressible Flows ◽  
Supersonic Flows ◽  
Load Cell ◽  
Test Facility ◽  
Supersonic Wind Tunnel ◽  
Tunnel System ◽  
Design Construction ◽  
Good Agreement

A mobile and affordable, miniature wind tunnel to aid students in studying high-speed compressible flows was constructed and tested. Millimeter-sized nozzles of different contours were fabricated to produce supersonic flows at Mach 2. The complete system consists of a converging-diverging nozzle, a load cell, pressure and temperature sensors, a tank to store high-pressure gases, and a computer-aided data acquisition system. The wind tunnel system is mounted to a cart, making it convenient to move. This test facility allows students to study and test supersonic flows in a safer environment while eliminating the high costs for a full-sized facility. Gas pressure was measured at various locations in the nozzle. A load cell consisting of four cantilever beams was constructed and used to determine the thrust of the nozzle. Data collected from each nozzle was compared to numerical simulations. In all cases, the simulations were in good agreement with the experimental data.

Supersonic Wind Tunnel Experiment on Aerodynamic Characteristics and Winglets Effects of the Tapered Supersonic Biplane

2011 ◽  
Author(s):  
Takashi Fujisono ◽  
Hiroshi Yamashita ◽  
Atsushi Toyoda ◽  
Hiroki Nagai ◽  
Keisuke Asai ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Type A ◽  
Aerodynamic Characteristics ◽  
Type B ◽  
Supersonic Wind Tunnel ◽  
Wing Model ◽  
Mach Numbers ◽  
The Difference ◽  
Wing Tip

The aerodynamic characteristics and the effects of tip plates of a tapered supersonic biplane wing during the starting process have been investigated through Experimental and Computational Fluid Dynamics (EFD/CFD). Three types of the wing model were used: without tip plate (type-N); with the tip plate which covers only the aft-half of the wing tip (type-A); with the tip plate which covers the entire wing tip (type-B). Experiment was conducted in the supersonic blowdown wind tunnel with 600 mm × 600 mm cross section located at the High-speed Wind Tunnel Facility of Institute of Space and Astronautical Science (ISAS/JAXA). The flow conditions covered from M∞ = 1.5 to 1.9 with increments of 0.1. Pressure-Sensitive Paint was applied to measure pressure distributions on the surface of the wing. CFD simulations were conducted to compare with experiments and to investigate effects of the Mach numbers in detail. The tapered biplane wing without the tip plate was found to start between M∞ = 1.8 and 1.9. The difference of the starting Mach numbers between type-N and type-A was small. On the other hand, the starting Mach number of type-B was about 0.05 higher than that of type-N.

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