NASA Glenn Research Center Flow and noise from septa nozzles Khairul Zaman and James Bridges NASA Glenn Research Center, Cleveland, OH 44135 SciTech 2017 Conference Dallas, January 10, 2017 Supported by Advanced Air Transport Technology (AATT) Project Advanced Air Vehicles Program 111 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Outline of talk: Introduction Experimental Facility Results and Discussion Summary 222 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Distributed Propulsion (From Felder, Kim & Brown 2009) In one (hybrid) version of the concept each passage is driven by an electric fan Concern about impact on noise. Will noise be greater than that from a equivalent single jet ? 333 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Scope of the paper: To study some of these aero- and acoustic issues with distributed propulsion, experiments have been conducted at NASA GRC This paper presents results of a smaller-scale fundamental experiment on the problem 444 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Experimental Facility Close-up view of nozzle and HW - Up to about 70 psig allowed - Microphones overhead - 8:1 rectangular nozzle (5.34" x 0.66“; D=2.12" ) Open Jet rig (CW17) - Inserts made by 3-D printing 555 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Experimental Facility (inserts) Internal geometry Top: ‘Fsh3’ has rectangular-circular-rectangular passage Bottom: ‘6Rec’ has rectangular passage throughout -Many other septa geometries are examined for maximum noise reduction 666 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center Septa Insert Notations Notation Description Fsh3 Septa TE flush with nozzle exit (rect-circ-rect passage) Fsh0 Duplicate of Fsh3 Insd Septa TE stops 0.25" upstream of exit OutF Full-width TE protrudes out by 0.175" Sclp Semi-circular cut-out (scallop) at septa TE 6Rec Same as Fsh0 or Fsh3 except rectangular passage Dsn5–10 Same as Fsh0 or Fsh3 except passages are non-uniform Fsh3 Insd OutF 777 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center SPL Spectra comparison at two jet Mach numbers  = 90°; mic on broadside of nozzle Fsh3 vs Bsln 6Rec vs Fsh3 90 90 M=1.00 d J d M=1.00 e e J re re g 85 g 85 g g a a ts ts s s ira 80 ira 80 p 0.90 p ,)B ,)B 0.90 (d 75 (d 75 L L P P S S 6REC M=0.903 104.9 BSLN M=0.902 106.0 j 70 FSH3 Mj=0.903 104.8 70 FSH3 Mj=0.903 104.8 j 6REC M=1.001 107.8 BSLN M=1.000 108.9 j j FSH3 M=1.002 107.6 FSH3 M=1.002 107.6 j j 10-1 100 101 10-1 100 101 f (kHz) f (kHz) Lower noise on low frequency end for the Flsh case. Not accounted for by exit area reduction (11% smaller D => 1.3 dB) Noise reduction with 6Rec case not as much 888 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center SPL Spectra comparison at two M j Fsh3 vs Insd Fsh3 vs OutF 90 90 d M=1.00 d M=1.00 e J e J re re g 85 g 85 g g a a ts ts s s ira 80 ira 80 p p ,)B 0.90 ,)B 0.90 d d ( 75 ( 75 L L P P S S INSD M=0.900 104.9 OUTF M=0.906 104.9 70 FSH3 Mj=0.903 104.8 70 FSH3 Mj=0.903 104.8 j j INSD M=1.002 108.1 OUTF M=0.999 107.7 j j FSH3 M=1.002 107.6 FSH3 M=1.002 107.6 j j 10-1 100 101 10-1 100 101 f (kHz) f (kHz) Noise reduction with Fsh3 is best so far 999 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC NASA Glenn Research Center SPL Spectra comparison at two M j Fsh3 vs Sclp Fsh3 vs Fsh0 90 90 d M=1.00 d e J e M=1.00 J r r e e g 85 g 85 g g a a t t s s s s ira 80 ira 80 p p , 0.90 , 0.90 ) ) B B d d ( 75 ( 75 L L P P S S SCLP M=0.902 105.1 FSH0 M=0.906 104.7 70 FSH3 Mj=0.903 104.8 70 FSH3 Mj=0.903 104.8 SCLP Mj=0.999 108.1 FSH0 Mj=1.002 107.4 FSH3 Mj=1.002 107.6 FSH3 Mj=1.002 107.6 j j 10-1 100 101 10-1 100 101 f (kHz) f (kHz) Noise reduction with Sclp and Fsh0 about same as that with Fsh3 111000 SciTech 2017 Dallas, TX Jan 9-13, 2017 Zaman/GRC