HomeNewsArticle Display

AEDC adds large-scale mass flow assembly calibration to test capability offering

Jay Caldwell, an outside machinist, works on venturis mounted inside the scavenging scoop in the 16-foot supersonic wind tunnel, Nov. 3, 2020, at Arnold Air Force Base, Tenn. The scoop was modified to allow for the calibration of a large-scale mass flow assembly. (U.S. Air Force photo by Jill Pickett)

Jay Caldwell, a commercial machinist, works on venturis mounted inside the scavenging scoop in the 16-foot supersonic wind tunnel, Nov. 3, 2020, at Arnold Air Force Base, Tenn. The scoop was modified to allow for the calibration of a large-scale mass flow assembly. (U.S. Air Force photo by Jill Pickett)

Nathan Payne, left, propulsion subject matter expert for the Flight Systems Test Branch, Test Division, Arnold Engineering Development Complex, watches data as it is collected during a test run in the 16-foot supersonic wind tunnel to calibrate a mass flow assembly, Nov. 19, 2020, at Arnold Air Force Base, Tenn. Calibration of large-scale MFAs is a new capability in 16S. Also pictured, Josh Webb, right, Analysis Flight commander, Flight Systems Test Branch. (U.S. Air Force photo by Jill Pickett) (This image has been altered by obscuring a badge for security purposes.)

Nathan Payne, Flight Systems Test Branch, Test Division propulsion subject matter expert and Josh Webb, Analysis Flight commander, Flight Systems Test Branch, watch data as it is collected during a test run in the 16-foot supersonic wind tunnel, or 16S, to calibrate a mass flow assembly, Nov. 19, 2020, at Arnold Air Force Base, Tenn. Calibration of large-scale MFAs is a new capability in 16S. (U.S. Air Force photo by Jill Pickett)

ARNOLD AIR FORCE BASE, Tenn. (AFNS) --

The Arnold Engineering Development Complex team stood up a new capability in the 16-foot supersonic wind tunnel at Arnold Air Force Base, Tenn. – hardware calibration for engine inlet testing.

An Aerodynamics Test Branch customer needed to calibrate their mass flow assembly, or MFA, for an upcoming high priority propulsion integration test. The MFA consists of an aerodynamic interface plane (AIP), a mass flow plug and ejector. The MFA system is used to simulate the throttle lever angle’s (TLA) mass flow through the test article. A facility capable of providing the needed uncertainty levels could not be found due to the large size of the MFA hardware.

The Aerodynamics Test Branch stepped up to meet this customer’s need, and as a result additional customers quickly requested to use the new capability for their future MFA calibration needs.

“MFA calibrations like this are unique in nature and are specific to wind tunnel testing,” said Nathan Payne, propulsion subject matter expert for the Aerodynamics Test Branch. “In the past, our test customers have had their own facilities to do this work. However, as those facilities wear out, or are sold off, our customers need a new solution.”

An MFA is attached to an aircraft model for testing in an aerodynamic wind tunnel. The MFA represents the engine mass flow rate into the inlet in order to characterize how the airflow into the engine is disrupted by the aircraft inlets and inlet ducting during maneuvers made by the aircraft throughout the flight envelope. Changes in the airflow can effect engine operations, specifically stall margin and pressure recovery.

The data gathered during the inlet testing are used to make distortion screens to replicate the altered airflows to the engine to increase real-world conditions during full-scale engine testing in engine test cells at Arnold AFB or at other original equipment manufacturers’ (OEM) engine test facilities. In an engine test cell, the engine is in a fixed position, therefore, it does not have airframe effects and is not representative of a full-mission envelope of conditions. The distortion screens allow test engineers to more closely simulate actual flight conditions.

  The MFA is calibrated in clean, dry, smooth and choked flow air so all losses between the AIP to the flow plug are captured. When the MFA is attached to an aircraft model, the only effects to data are the distortions caused by the model design and model attitude. This allows for comparisons to different configurations at the same TLA, or corrected mass flow, setting.

Each engine that is being simulated by an MFA has to have a mass flow assembly calibration or, at minimum, a calibration verification. There are multiple facilities around the nation that have this capability. However, the large size of the system under test drove the need to perform the work at Arnold AFB. A large scale model provides high fidelity data which leads to a lower margin of error when scaled up for engine testing.

The 16-foot supersonic wind tunnel, or 16S, will provide a unique flow measurement capability that utilizes a choked venturi for more accurate mass-flow measurements. This measurement technique is one that most OEMS do not have in their wind tunnels. A choked venturi allows test engineers to reduce the number of measurements that need to be taken, which reduces instrumentation, preserves flow quality and reduces overall measurement uncertainty.

“Our customers in the past have not had the ability to calibrate MFAs at different atmospheric pressures, which ensures no Reynolds numbers effect in the data,” Payne said. “They also have not been able to provide dry air to the MFA resulting in humidity errors, or the need for a humidity correction. Last, in some cases customers could not keep the venturi choked for all flow rates needed.”

The calibration is conducted by mounting the MFA to the scavenging scoop in 16S. The scoop was designed for the purpose of removing exhaust from the airflow when testing air-breathing engines and rockets ensuring non-vitiated flow because 16S is a continuous flow tunnel. A set of venturis was mounted inside the scoop and then the MFA was mounted to the front of the scoop via an adaptor plate. When not needed for MFA calibration, the scoop can be returned to the standard configuration.

Standing up this new capability was accomplished through a collaboration of expertise from across AEDC. Payne drafted the plan and did the initial calculations. Computational fluid dynamics engineers then verified that the theoretical should be possible. From there, design engineers took over to design the hardware to ensure it could withstand the test conditions. Payne approached the Propulsion Test Branch to secure the venturis needed. Then, AEDC craftsmen fabricated the parts needed to modify the scoop and installed the hardware.

“AEDC was able to utilize the different skill sets here on base to retrofit the suction scoop and added a new metered airflow capability for our customers to an existing world-class facility,” Payne said.

 The wind tunnel, known as Tunnel 16S, has been the focus of a major multi-year effort to return the facility to service to provide additional testing capacity for large-scale models, and to expand the test envelope available for testing those models.

This capability does not require the use of the main drive compressors, but did contribute to the return-to-service effort through checkouts of the data systems, which are the same systems that will be used once the tunnel is fully operational. Other systems checked out and utilized during the calibration were the controls system, the real-time data displays and the analysis stations. The tunnel was also pumped down using the plenum evacuation system (PES), providing an opportunity to “exercise” the tunnel, including valves that must be opened and closed for operations.

The high demand for the 16-foot transonic wind tunnel increases the importance of returning 16S to service and of this new capability. If the large-scale MFAs had to be calibrated in 16T, there would be a significant loss of test time.

“The original design I had was to utilize the 16T scoop, however, as more customers showed interest, the 16S systems started to come online, and with a successful leak check of the 16S circuit, the 16S scoop presented itself as a viable test option,” Payne said. “A walk-down of the flow path by the TOE (test operations engineer), myself and plant engineers; favorable CFD runs; and a fairly open test schedule, we knew we had found the right place for this capability.”

Engage

Twitter
The @AF_Academy is committed to developing leaders of character. Their graduates have always inspired others. Soon,… https://t.co/rjSmH70SN8
Twitter
RT @HQ_AFMC: #success! This is the 6th flight of the Valkyrie for @AFResearchLab & the first time the payload bay doors have been opened…
Twitter
Don't miss this event LIVE at 3 p.m.! https://t.co/CFkBHJMCsi
Twitter
.@TeamTyndall's SrA Can Liu deployed to support the #COVID19 vaccination efforts in New York. She is the only Airma… https://t.co/LIfeJ48lNL
Twitter
The newest aircraft in the #AirForce fleet has been christened the F-15EX Eagle II. The Eagle II includes the lates… https://t.co/4TIA52fk06
Twitter
Congratulations to the Royal Danish Air Force on the delivery of their first F-35 today! Our Danish friends have be… https://t.co/Gg4fduigTg
Twitter
RT @GenCQBrownJr: Thank you to @Princeton for having me speak today with their University Lecture Series. I greatly appreciate the opportun…
Twitter
#DYK The #AirForce is the only military branch that has service-wide guidance on acquisition programs, defining cyb… https://t.co/UJZcxugySn
Twitter
RT @366FW: Air Force Chief of Staff @GenCQBrownJr shares some words of wisdom with our Gunfighters! Our Airmen continue to #acceleratecha
Twitter
April is recognized as the Month of the Military Child. The ever-changing military lifestyle impacts every member o… https://t.co/hmvocXQaGL
Twitter
Airmanship 200 is the second of three development courses that new #Airmen receive to better understand #AirForce v… https://t.co/1rueS9ToLP
Twitter
#ICYMI -- The Department of the Air Force published a website where #Airmen and @SpaceForceDoD #Guardians can acces… https://t.co/0YJcST5XaT
Twitter
Combating #COVID19 one shot at a time. https://t.co/EVyenHCi5D
Twitter
The Department of the Air Force-Massachusetts Institute of Technology Artificial Intelligence Accelerator is helpin… https://t.co/cfsdOX43hY
Twitter
.@LRAFB, Arkansas, Airmen completed 106 sorties, 254 flying hours, and nearly 2,000 training events during a multi-… https://t.co/3YOSh8DvcT
Twitter
Today is Gold Star Spouses Day. It honors the surviving loved ones of military service members killed in the line o… https://t.co/JYCacpkds5
Twitter
Everyone is susceptible to invisible wounds. These wounds have an impact can develop at any time, in any place, in… https://t.co/XxPKyovJc9
Twitter
#AirForce Civil Engineer Center Operation Directorate teams are following safety protocols and working closely with… https://t.co/4IjMrV240S
Twitter
RT @grandslamwing: Beware of frostbite 🥶 Our #TeamAUAB cryogenics team brave the heat of the flightline to deliver aircrew the frigid, but…
Twitter
Being able to recognize an invisible wound could save a life. Learn more about available resources here:… https://t.co/M9JOy6XRWn
Facebook
The newest Air Force Podcast recently dropped. Listen to a small snippet of CMSAF Kaleth O. Wright talk with Staff Sgt. New about resiliency. Listen to the entire podcast on Youtube: https://go.usa.gov/xpnAD or Subscribe to The Air Force Podcast on iTunes: https://podcasts.apple.com/podcast/the-air-force-podcast/id1264107694?mt=2
Facebook
Our mantra, "Always ready!" It's the spirit we fly by! #B2Tuesday
Facebook
Need some motivation to get your week started off right? Listen as CMSAF Kaleth O. Wright weighs in...
Facebook
The U.S. Air Force Academy gives its cadets some unique opportunities. Ride along one of this opportunities.
Facebook
A United States Air Force KC-135 Stratotanker refuels an F-22 Raptor over northern Iraq, Nov. 6, 2019. U.S. Central Command operations deter adversaries and demonstrate support for allies and partners in the region. (Video by Staff Sgt. Daniel Snider)
Facebook
Although the Silver Star is the third-highest military medal, it's not given often. Today, TSgt Cody Smith was the 49th Special Tactics Airman to receive this medal since Sept. 11th, 2001. Read more of TSgt Smith's amazing story: https://www.airforcespecialtactics.af.mil/News/Article-Display/Article/2024815/special-tactics-airman-battled-through-injuries-awarded-silver-star/fbclid/IwAR2LZWwx1VHdTnQe39rIEBOuJS_0JvMQBBGt7I-E6zsxxn-Lx9387yu43Bc/ Cannon Air Force Base Air Force Special Operations Command United States Special Operations Command (USSOCOM) U.S. Department of Defense (DoD)
Facebook
Tune in as our Air Force musicians along with other military musicians are awarded the National Medal of Arts.
Facebook
Like Us
Twitter
1,340,495
Follow Us