1、0-. -ir ,.FLIGHT DE TERNIINATION OF DR4G AND PRESSURE RECOVERYOF A NOSE INLET OF PAWBOLIC PROFILE AT -,MACH NUMBERS FROM 0.8 TO 1.7By Richard I. Sears and C. F. MerletLangley Aeronautical LaboratoryLangley Field, Va.NATIONAL ADVISORY COMMITTEEFOR AERONAUTICSWASHINGTONOctober 15, 1951Provided by IHSN
2、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-=.- .-_., .: g = , .-.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA I?14L51JZ02 -. -NATIONAL ADVISORY COMWKE FOR AERONAUTICSRESEARCH MEMORANDUMFLIGEIDETERMINAT
3、ION OF DRAG AND PRESSURE RECOVERYOF A NOSE INLET OF PARABOLIC PROFILE ATMACH NUMEERS FROM 0.8 TO 1.7By Richard 1. Sears and C. F. MerletSUMM4RYA ducted mcdel having a nose inlet whose external contour wasdefined by a parabolic arc was flight-tested at zero amgle of attack.External drag coefficient a
4、nd total-pressure recovery at the end of theM diffuser were,measured over a range of Mach nunihersfrom 0.8 to 1.7 anda range of mass-flow ratios from 0.23 to 1.0. The Reynolds number based on the 10-inch body diameter varied from about 4 x 106 to 9 x 106At supersonic speeds, the parabolic inlet mdel
5、 had about the samedrag coefficient as the basic arabolic body from which it was derived.At low supersonic speeds,the drag of the parabolic inlet was about thesame as that of an NACA 1-40-250 nose inlet previously tested. AtM= 1.7, however, the drag coefficient of the NACA 1-40-250 inlet mcdelwas 37
6、 percent greater than that of the parabolic inlet mcde.At 0.8 mass-flow ratio, the total-pressure recovery of the presentmodel exceeded that of an etiernal-compression supersonic diffuser atMach numbers less than 1.4. The reverse was true at higher speeds.The use of a 2.5 diffuser angle eliminated t
7、he separation and associ-ated large losses in total-pressure recovery at high mass-flow ratiospreviously measured for an 8.2 diffuser.INTRODUCTIONData pertaining to the dragassociated with air inlets at transonic “and supersonic speeds are meager relative to that currently a+railable* i“orwings and
8、bcdies. In order to investigate the transonic character-istics of air inlets, the Pilotless Aircraft Research Division of theLangley Aeronautical Laboratory is undertaking a series of tests ofrocket-propelled models in free flight. The technique involves flying.Provided by IHSNot for ResaleNo reprod
9、uction or networking permitted without license from IHS-,-,-2 NACA RM L51X02 “- “+,.ducted bodies with various types of air inla and meuring the totaldrag, the inrnaldrag, and the total+preqre recovy as functions.of Mach nuniberand mass flow. ,- Data have been obtained in this manner ”forthe NACA 1-
10、40-250 noseinlet-and are reported in.reference 1. As a continuation of the sameprogram, another nose inlet and diffuser deigned to ve low drag andgood pressure recovery at low”supersonicMach numbers-ire flight-tested._, _.-1.-.The results obtained are presented herein.-me md.el.;ms tested at theLang
11、ley Pilotless Aircraft Research Station “atWallops Island, Va. ,“”=SYMBOLS “ ()D7P Mo2Af2dragmassmasscoefficientflow through duct .: +=u -mm.-,.floting through a stream tube of area -the Mach number increased further. -= -.As indicated in figure k, the maximum mass-flow i?atiovaried with HMach numbe
12、r and a mass-flow ratio of 1 was obtained only at M 1.65.The drag-coefficient curve of figure 6 for -M= 1.7 indicates that the ., :drag varies smoothly with mass-flow ratio right UP W = 1.0. It- “ -seems reasonable to expect that if the internal contractionhad been .eliminated so as to permit a mass
13、-flow ratio of 1 at lower Mach numbers,the drag coefficientwould have been that indicated by extrapolation of .-the curves of figure 6 to = 1. It is therefore apparent that, bylimiting the maximum m/ %ttainable, th :. x,- :-:.- :-_=-“ .u, . _s .Provided by IHSNot for ResaleNo reproduction or network
14、ing permitted without license from IHS-,-,-NACA.RM L51E02The dashed-line curves of figure 9 show9the pressure recoveries. reported in reference 5 for an external-compressionsupersonic inleta71(Ferri type, 30 cone). At 0.8 mass-flow ressure recoveriesof the present inlet-diffuser combination exceed t
15、hose for the supersonicdiffuser at Mach numbers less than 1.4. At Mach numbers higher than 1.4the external-compressiondiffuser was superior from the standpoint ofpressure recovery.CONCLUSIONSFlight-test results for a parabolic nose-inlet maiel and comparisonof these with other data indicate the foll
16、owing:1. At all speeds tested the drag coefficient ofthe parabolic nose-inlet model was about the same as that of the basic parabolic body fromwhich the inlet moiel was derived. At a Mach number of 1.1, the dragcoefficient of both mdels reached a maximum and decreased as the Machn number increased f
17、urther.2. The parabolic nose inlet and the NACA 1-40-250 nose inlet modelshad about the ssme drag coefficient at low supersonicMach numbers. As.the Mach nuxaberincreased further the drag-coefficient curves of thetwo md.els diverged. At a Mach number of 1.7, the NACA 1-40-250 inletmodel had about 37
18、percent greater drag than the parabolic-inlet model,3. me drag coefficient increment associated with operation atmass-flow ratios less than one was less than that due to the additivedrag alone because of a reduction in bcdy pressure drag. The use ofan internal contraction ratio of 0.88 at the inlet
19、to provide a bell-mouth for subsonic oeration was therefore not accompanied by severedrag penalties.4. At 0.8 mass-flow ratiO, the total-pressure recovery at the endof the diffuser exceeded that of an external-compression supersonicdiffuser up to a Mach number of 1.4. At higher Mach numbers theexter
20、nal-compressiondiffuser was superioy.5. Use of an initial diffiser angle of 2.5 eliminated the sea-tioh and consequent large total-pressure losses at high ss-flow ratiospreviousljjmeasured for an 8.2 diffuser.-!.Langley Aeronautical LaboratoryNational Advisory Committee for AeronauticsLangley Field,
21、 Va.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 ccmRwElme NACA RM L51X02REFERENCES1. Sears, Richard I., and Merlet, C. F.: Flight Determination of theDrag ”andPressure Recovery of an NACA l-kO-250Nose Inlet at MachNutiers fromO.9 to 1.8. llACA
22、 RML50LlfJ, 1951. “2. Von Kan, Thecdor, and Moore, Norton B.: Resistance oSlender “Bodies Moving with Supersonic Velocitie with Special Referenceto Projectiles. Trans. A.S.M.E., vol. 54, no. 23, Dec. 15, 1932,PP. 303:310.3. Van Driest-,E. R.: Turbulent Boundary Layer in Compressible Fluids.JourAero.
23、 Sci., VOL 18, no. 3, March 1951, pp. 14+5-160,216.4. Beet-on,A. B. P.: Curves for the Theoretical Skin Friction Loss inAir Intake Ducts. TN No. Aero 2035, British R.A.E., Feb. 1950.5. Ferri, Antonio,a New Ty_peofand Nucci, Louis M.: Preliminary Investigation of .Supersonic Inlet. NACA TN 2286, 1931
24、.-.=-. .:-. :n-.*.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, . .“mI%*,:I ,:.,.-=Pg=-L-67265.1Figure l.- Photograph of the model.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.,-i6wal10rificw
25、10.00m. dlam“J/w.-. - _ . _1 . _ _ _ _ _ . zk.oo 30.55- 1.72T5.50kFigure 2.- Drawings(a) General arrangement.i.of the model. All dimenaion,g are in inche8. “Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Lip Coordluai%sx 7 x YO.m O.coo O.lho 0.065.0
26、18 .021 a7121O .077.035 .032 .280 slob.Op .0117 .420 .088.1C6 .C67 .50 a71WL.J!.radiua, 0.012L.012 radinadi2.83 dlam. IilpLdlap 1.2PP.ll%3b01ia(ref. 1)./JMeamr-Jng 8tatimI L(b) Details of the Inlet and diffuser.Figure 2.- Concluded.Provided by IHSNot for ResaleNo reproduction or networking permitted
27、 without license from IHS-,-,-14 NACA RM L51E02/Qxm6/a718 LoFigure 3.- Variation ofnumbers are basedL?M*Reynolds numberon maximum body=s=.b.with Mach nymber. Reynoldsdiameter of:10inches.-.-*-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. , 1 ,1.
28、0(/9./%).:eor .611(h/no)hax.4.20/ onc-dimenional flw theo.8 ,9 Lo L/ L2 i3 /.4 /,5 16M. /.718Figure h.- Meaaured and computed values of the llEU3B-fbW It3ti0.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.32.28.24.24./6CD./2,08.040NACA RM L51-E02NA
29、CA /-40-250 , mm. , 0.8. mjm “0.4# 1W I f -G(rcf 1). !Estimated fin drag : - - - - - .- - - - - -.8 .9 1(7 L/ /.2. /,3 L+M.Figure 5.- Variationof external drag coefficientfor various mass-flow”ratios.i5 L6 17-tliMach numberProvided by IHSNot for ResaleNo reproduction or networking permitted without
30、license from IHS-,-,-3a71*.NACA RM L51-E02 , 17.32a71Z8,/?4,20-u-i?.I 1 I 1 I 1 1 1 1 1 I II I I I I I I I I IFigure 6.- Variation of external drag coefficient with mass-flow ratiofor several Mach numbers.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,
31、-,-18 NACA RM L51X02s-.-,28rtdO/lC bQdy(tots/ Lj - base CD).20 /*Ex fera / CD - czddtf(Ve CD.-./6,/2s08.04-“0 J? .+ .6 -Y .,8 LomhvFigure 7.- Measured external putedat a Wch number ofadditive drag-coefficients1.4.“bProvided by IHSNot for ResaleNo reproduction or networking permitted without license
32、from IHS-,-,-(?.-,3,2CD./0, ,-/ +-x+1 1 a 1TI1 I 1 11 a71o Lo 40lo let stffion , Xd”Figure 8.- External drag coefficient for n fmdly of parabolic inlets,Jg% = 1.0; = 1.4.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.M,9Oftiot+mo- _/ -Lo.- - - :- _
33、- - =-. _ :i8-.4-,8.8- Refcreocc 5 (erri type 300 czwe )P+-e.reh t tcrfsT.740 .Figure 9.- Variation of total-presBm recovery with Mach nuniber forseveral masa-flpw ratios, 1 IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.NACA RM L51E02 21Lo Alo/ a
34、 9 /*z-/.4.9i/Y.“ = -/.6 . . -/,7.$=s=”.7 Ao,4 .6 a71a24 Figure 10.- Variation of total-pressure recovery with mass-flow ratioat several Mach numbers.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-22 NACA RM L51X02w./.00.9692ti/h,88.84Q.ItI/7ifial d
35、iffuser angle2,5 8.20 MO1 d 0.90 d 1.4o“ C5 /.7,2 .4 .6 .$ /.0.T !“” -Mach number at diffuser en france , A?,Figure 11.- Comparison at several free-stre& Mach numbers of the .-performance of the 8.2 subsonic diffuserthat for the 2.5 diffuser of the present of reference“1withtests. -.a71.NACA-LanIY -10-15-S1- 325. . .-. -.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
