An Overview of the A3 Subscale Diffuser Test Project

Ryan, James E.; Mulkey, C.H.; Raines, N. G.; Saunders, Grady

doi:10.2514/6.2008-4365

Cited by 8 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to the mission-criticality of having a reliable and successful A-3 facility, a sub-scale diffuser test facility (SDT), shown in Figure 2, was built and tested at the NASA-SSC E-Complex 7 . The subscale facility was designed such that it was aerodynamically similar to that of the full-scale A-3 facility.…”

Section: A A-3 and Sdt Altitude Test Facilitiesmentioning

confidence: 99%

Reduction of Altitude Diffuser Jet Noise Using Water Injection

Allgood

Saunders

Langford

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Self Cite

View full text Add to dashboard Cite

A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser. Nomenclature D DE= exit diameter of altitude diffuser D WJ = diameter of noise suppressor water jets J = momentum flux ratio of a single water jet to the altitude diffuser exhaust jet OSPL = overall sound pressure level, dB (reference pressure = 20e-6 Pa) r = radial location SDT = sub-scale diffuser test facility V WJi = exit velocity of an individual water jet from the noise suppressor V SDT = exit velocity of SDT altitude diffuser W A3 = total mass (weight) flow rate of A-3 altitude diffuser W SDT = total mass (weight) flow rate of SDT altitude diffuser W WJ = total mass (weight) flow rate of water jets x = axial location ρ = density

show abstract

Section: A A-3 and Sdt Altitude Test Facilitiesmentioning

confidence: 99%

Reduction of Altitude Diffuser Jet Noise Using Water Injection

Allgood

Saunders

Langford

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Self Cite

View full text Add to dashboard Cite

show abstract

“…(An overview of the originally scoped test project was presented at the 27th AIAA Aerodynamics Measurement and Ground Testing Conference [8].) Upon completion of this original series of tests, NASA recognized the value of the SDT test setup as a testbed appropriate for further A-3 risk miti gation testing.…”

Section: Introductionmentioning

confidence: 99%