US2618972A - Testing apparatus for scale models of aerodynamic ducts - Google Patents

Testing apparatus for scale models of aerodynamic ducts Download PDF

Info

Publication number
US2618972A
US2618972A US243658A US24365851A US2618972A US 2618972 A US2618972 A US 2618972A US 243658 A US243658 A US 243658A US 24365851 A US24365851 A US 24365851A US 2618972 A US2618972 A US 2618972A
Authority
US
United States
Prior art keywords
model
duct
scale
scale duct
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US243658A
Other languages
English (en)
Inventor
Leduc Rene
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US2618972A publication Critical patent/US2618972A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
    • F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
    • F01D21/003—Arrangements for testing or measuring
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/02—Wind tunnels
    • G01M9/04—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/06—Measuring arrangements specially adapted for aerodynamic testing

Definitions

  • the present invention relates to a testing apparatus for scale models of aerodynamic ducts, and more particularly to a model-scale duct having an outer shell beingthe replica of the outer shell of a full-scale duct operating with combustion means,
  • a testing apparatus comprises in its broadest aspect a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged within the full-scale duct, the model-scale duct having an entry end and an exit end, means for supporting the model-scale duct in an air stream, and a body having a surface of revolution formed by a curved line, the body being arranged within the model-scale duct substantially coaxially with the same and extending from a point spaced from the entry end of the model-scale duct at least to the exit end thereof so as to form an annular air passage between the model-scale duct and the body, the body being shaped so that at any crosssection perpendicular to the axis of the body the ratio of the cross-sectional area of the annular air passage between the body and the model-scale duct to the total'internal cross-sectional area of the duct is equal to the square root of the ratio of the density of heated air at the temper-aure prevailing
  • the body has a rounded leading end located substantially at the zone of maximum cross-section of the model-scale duct.
  • the body includes a portion having a substantially cylindrical and constant crosssection, the portion being located outside and beyond the exit end of the model-scale duct.
  • an element preferably designed as a grid is arranged in front of the leading end of the body, the element restricting the flow of air through the model-scale duct so as to imitate the loss of pressure due to the combustion means operating in the full-scale duct.
  • the element is attached to the leading end of the body and disposed perpendicularly to the axis of the model-scale duct.
  • a testing apparatus comprises in combination, a wind tunnel, a model-scale duct arranged coaxially to the wind tunnel, the modelscale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, the modelscale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of the model-scale duct; balancing means supporting the model-scale duct in the air stream through the wind tunnel, a body rigidly connected to said wind tunnel and having a surface of revolution formed by a curved line, the body being arranged within the model-scale duct substantially coaxially with the same and extending from a point spaced from the entry end thereof so as to form an annular air passage between the model-scale duct and the body, the body being shaped so that at any cross-section perpendicular to the axis of the body the
  • Fig. 1 is a sectional elevation of a full-scale duct
  • Fig. 2 is a sectional elevation of a wind tunnel and a model-scale duct according'to the invention.
  • Fig. 3 is a modification of the model-scale duct shown in Fig. 2.
  • the full-scale duct l comprises a divergent entry diffuser 2 and a convergent exhaust nozzle 3, between which the duct is provided at its maximum cross-section with internal means t, diagrammatically represented, for heating the air flowing through it.
  • the means 4 comprise fuel burners.
  • the air enters the duct with velocity V and is exhausted after being heated by the means 4 with velocity V3, indicated by arrows.
  • the arrows 5 represent the internal pressures experienced by the duct-wall, such pressures being normal to the wall.
  • the areas of a number of cross-sections of the duct are represented by Q0, 91, 9'1, 92 and Q3.
  • the area 90 at the entry is less than the area (23 of the nozzle exit. 91 is equal to '93. and 9'1 is equal to (22.
  • the model-scale duct I likewise comprising a divergent entry diffuser 2' and a convergent exhaust nozzle 3, is geometrically similar to the full-'scaleduct. of Fig. 1.
  • a body 6 Coaxially placed therein is a body 6 which extends downstream of the duct as shown at 1 to a mounting 8 such as arms connected to the wind tunnel I'Z "at a location downstream of the model-scale duct 1 and remote from the duct with which the arms 8, havev no physical connection, so that aerodynamic forces experienced by the body 6 are not transmitted to the tunnel balance 9, ID.
  • the arms '8 cause only a small disturbance in the outflowing air since the arms 8 are disposed at a distance from the model-scale duct l which is a multiple of the length model-scale duct l.
  • the model-scale duct I is pivoted to two links 9 and I0 forming part of the tunnel balance and having their other ends pivoted to a supporting element 13.
  • the link It) is under the action of a spring ll connected to a sta tionary part M.
  • the spring I I allows to measure the thrust exerted by the air on the model-scale duct I.
  • the body 6 is so shaped that at any crosssection the cross-sectional area of the annulus p is the density of air at ambient temperature;
  • .12 is the density of air at the temperature attained in the full-scale duct at the corresponding cross-section when operating with the heater 4 (see Fig. 1) in action.
  • the leading end of the body 6 is of rounded form to prevent the generation of turbulence by too abrup't a change of cross-sectional area of the air-passage, and the part of the body extending outside the duct is of cylindrical form for a considerable distance downstream, as shown in Fig. 2, in which the cross-sectional area wa is indicated as constant downstream of the nozzle-exit.
  • the latter feature ensures that the presence of the body 6, 1 does not modify the character of the air-flow outside the ductand give rise to aerodynamic forces on the model which are unrepresentative of the full sc'ale arrangement.
  • the velocities at corresponding cross-sections when reduced to the same scale must be inversely proportional to the square-roots of the corresponding air: densities p', and p, so that a VI p7 V P where V is the velocity at section 9 in Fig. 2 without heating and V is the velocity, with heating, at the corresponding sectionof Fig. lreduced to model-scale. Further the mass-flow through the duct must be the same in both cases so that the mass-flow with heating across any cross-section :2 of the duct shown in Fig.
  • Equation 2 L'reducdto model-scale, must be equal to that withouthe'atin'g across the corresponding annular section 9w, of the duct shown Fig. 2, so that V'(-K2e) "'VQ (3*) which by substitution from Equation 2 becomes the Equation 1 above-stated.
  • Equation 2 gives the relation of the velocity V'n. at the nozzle exit of the arrangement of. Fig. :2,to the corresponding velocity V3 in the arrangement of Fig. -1 reduced to model-scale.
  • FIG. 3 a modification of the body 6 of the, model-scale duct 1? is shown which is. intended to take into account certain differences between the real thrust which is measured and that resulting from calculation.
  • W3 is the cross-sectiono'fthe gas at. avery large distance downstream of theduct (that is, a real section in case of a full-scale duct, and
  • W is the cross-sectional area of the air flow at a very large distance from the entry of the duct
  • A is equal to g3 and go are, respectively, the specific gravities of the air at a very large distance downstream and upstream of the duct
  • V3 and V0 are, respectively, the velocities of the air flow at the very large distance downstream and upstream of the duct.
  • the value of A can be derived from the Expression 5 by two measurements of the total pressure downstream and upstream of the duct. However, it can be derived also from the Expression 4 by a measurement of the thrust exerted on the duct in the wind tunnel. Generally the value of A derived from the Equation 4 is smaller than that derived from the Equation 5.
  • a loss of pressure is created within the model-scale duct by providing in the same an element such as a grid 15 which is preferably attached to the leading end of the body 6 and disposed perpendicularly to the axis of the model-scale duct l.
  • the dimensions of the grid are determined so that the values of the term A derived from Equations 4 and 5 are identical with each other. It can be shown that if this is the case the loss of pressure 101-192, :01 and 102 being the pressures upstream and downstream of the grid, is the same as that caused by the combusion means in the full-scale duct.
  • the grid [5 has no physical connection with the model-scale duct l.
  • a sufficient distance is provided between the edge of the grid l5 and the model-scale duct I in order to eliminate any frictional forces which could disturb the measurements of the thrust exerted on the model-scale duct 1 which are measured for instance by means of the wind tunnel balance 9 to 14 shown in Fig. 2.
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with, combustion means arranged within the full-scale duct, said model-scale duct hav- 6 ing an entry end and an exit end; means for supporting said model-scale duct in an air stream; and a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the total internal cross-sectional area of said model-scale duct is equal to the square root of the ratio of the density of heated air at the temperature prevailing at
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; and a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; and a body having a surface of revolution formed by a, curved line, said body being arranged within: said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least.
  • model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct 'op-' erating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from'the entry end thereof to axzone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surfaceof revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passagebetween said model-scale duct and said body, said body being shaped so that at anycross-section perpendicular to the axis of said body the ratio of the cross-sectional.
  • a model-scale duct having. an outer shell: being, the replicaof the outer shell of a 'full sca-le duct operating with combustion means arranged at the largest cross-section of the full-scale'duct, said model-scale duct.
  • model-scale duct having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasingfrom the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface ofrrevolution formed by a curved line, said body being arranged within said modeL-scale duct substantially coaxially with the same and extending from a point spacedfrom said entry end 'of said model-scale duct at least-to the exit end. thereof so as to form an annular air passage between said model-scale duct and said.
  • said body being shaped so thatiat anyv cross-sectionperpendicular to theaxis of said body the ratioof thecross-sectional area of said annular air passage between said body and saidmodel scale 'duct to the totalinternal cross-sectional area of said model-scale duct is equal to-thesquare root of th ratio of thedensity of heated air at the temperature prevailing at'the corresponding axial cross-section in aheated full-scale duct operating with combustion means to the density of air at the prevailing ambient temperature of saidairstream, said body having arounded leading endlocated substantially at the zone-of 8 maximum cross-section of said model-scale duct; and a portion for-'ming part of said bodya'nd having a substantially cylindrical constant crosssection, said portion being located outside and beyond the exit end of said model-scale duct.
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross seotion increasing from the entry end thereof to a zone of maximum cross-section and decreasing.
  • model-scale duct means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale ducfsubstantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the total internal cross-sectional area of said model-scale duct is equal to the square root of the ratio of thedensity of heated air at a temperature pre vailing at the corresponding axial cross-section in a heated full-scale duct operating with combustion means to the density of air at the prevailing ambient temperature of said air stream; and a portion forming part
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at th largest cross-section of the full-scale duct, said model-scale duct having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model scaleduct in an air stream; a body having '.a surface of revolution formed by acurved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale ductat least totheexit end thereof so as to form an annular air'passage between said model scale ductlandv said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of thec'ross-sectional area of said annular air passage between said body and
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said modelscale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any crosssection perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model- 'soale duct
  • a model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said modelscale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross- :section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model- ;scale duct
  • a model-scale duct having an outer shell having the replica of the outer shell of a full-scale duet operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variablecross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the total
  • a model-scale duct having an outer shell having the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable crosssection increasing from the entry and thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved zone of line, sa1d body being arranged Within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said modelscale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct
  • the total internal cross-sectional area of said model-scale duct is equal to the square root of the ratio of the density of heated air at the temperature prevailing at the corresponding axial cross-section in a heated full-scale duct operating with combustion means to the density of air at the prevailing ambient temperature of said air stream, said body having a rounded leading end located substantially at thezone of maximum crosssec tion of said model-scale duct; and a grid attached to the leading end of said body, said grid restricting the flow of air through said modelscale duct so as to imitate the loss of pressure due to the combustion means operating in the full-scale duct.
  • a model-scale duct having an outer shell having the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable crosssection increasing from the entry end thereof to av zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the total
  • a model-scale duct having an outer shell having the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scalev duct having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; means for supporting said model-scale duct in an air stream; a body having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entryend of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said modelscale duct and said body,- said body being shaped so that at any cross-section perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said model-scale duct to the total
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combusion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing fromthe entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end-of said model-scale duct; balancing means supporting said model-scale duct in the air stream through said wind tunnel; and a body rigidly connected to said Wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said modelscale duct substantially coaxially with the same and extending from a.
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale ductoperating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model scale duct; balancin means sup porting said model-scale duct in the air stream through said wind tunnel; a body rigidly connected to said wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section per
  • the crosssectional area of said annular air passage between said body and said model-scale duct to the total internal cross-sectional area of said duct is equal to the square root of the ratio of the density of heated air at the temperatureprevailing at the same axial cross-section in a heated full-scale duct operating with combustion means to the density of air at the prevailing ambient temperature; and a portion forming part of said body and having a substantially cylindrical constant crosssection, said portion being located outside and beyond the exit end of said model-scale duct and being rigidly connected to said wind tunnel.
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; balancing means supporting said model-scale duct in the air stream through said wind tunnel; a body rigidly connected to said wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; balancing means supporting said model-scale duct in the air stream through said wind tunnel; a body rigidly connected to said wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duet having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; balancing means supporting said model-scale duct in the air stream through said wind tunnel; a body rigidly connected to said Wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said model-scale duct and said body, said body being shaped so that at any cross-section perpendicular to the
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged ooaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable crosssection increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; supporting said model-scale ductiin the air stream through said wind tunnel-y a body rigidly connected to said wind tunnel and having a surface of revolution formed by a curved line, said body being arranged within said model-scale duct substantially coaxially with the: same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof so as to form an annular air passage between said modelscale duct and said body, said body being shaped so that at any cross-section perpendicular to the
  • a testing apparatus comprising in combination, a wind tunnel; a model-scale duct arranged coaxially within said wind tunnel, said model-scale duct having an outer shell being the replica of the outer shell of a full-scale duct operating with combustion means arranged at the largest cross-section of the full-scale duct, said model-scale duct having a variable cross-section increasing from the entry end thereof to a zone of maximum cross-section and decreasing from the zone of maximum cross-section to the exit end of said model-scale duct; balancing means supporting said model-scale duct in the air stream through said Wind tunnel; a body rigidly con- 16 nected to said wind tunnel and.
  • model-scale duct having a surface of revolution formed by a curved line
  • said body being arranged within said model-scale duct substantially coaxially with the same and extending from a point spaced from said entry end of said model-scale duct at least to the exit end thereof soas to form an annular air passage between said model-scale duct and saidbody, said body being shaped so that at any crosssection perpendicular to the axis of said body the ratio of the cross-sectional area of said annular air passage between said body and said modelscale duct to the. total internal cross-sectional area of said model-scale duct is equal to the square root of the ratio of the density of heated air at the.
  • a heated full-scale duct operating with combustion means to the density of air at the prevailing ambient temperature of said air stream
  • said body having a rounded leading end located substantially atv the zone of maximum cross-section of said modelscale duct; a portion forming part or said body and having a substantially cylindrical constant cross-section, said portion being located outside and beyond the exit end of said model-scale duct and bein rigidly connected to said wind tunnel; and a. grid disposed perpendicularlyto the axis of said model-scale duct and attached to the leading end of said body, said grid restricting the flow or air through said model-scale duct so as to imitate the loss of pressure due to the combustion means operating in the full-scale duct.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
  • Testing Of Engines (AREA)
US243658A 1948-03-12 1951-08-25 Testing apparatus for scale models of aerodynamic ducts Expired - Lifetime US2618972A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1117104T 1948-03-12

Publications (1)

Publication Number Publication Date
US2618972A true US2618972A (en) 1952-11-25

Family

ID=9629808

Family Applications (1)

Application Number Title Priority Date Filing Date
US243658A Expired - Lifetime US2618972A (en) 1948-03-12 1951-08-25 Testing apparatus for scale models of aerodynamic ducts

Country Status (4)

Country Link
US (1) US2618972A (de)
DE (1) DE860558C (de)
FR (2) FR1117104A (de)
GB (2) GB664055A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2799160A (en) * 1955-03-28 1957-07-16 North American Aviation Inc Wind tunnel air flow control
US2995932A (en) * 1953-06-24 1961-08-15 Jr Everett J Hardgrave Device for measuring mach number
US5235848A (en) * 1991-11-27 1993-08-17 The United States Of America As Represented By The Secretary Of The Navy Thruster test fixture
CN103486984A (zh) * 2013-10-12 2014-01-01 中国人民解放军63926部队 一种风洞内型面同轴度的检测方法
CN105571766A (zh) * 2014-10-11 2016-05-11 中国航空工业集团公司西安飞机设计研究所 一种风洞模型表面压力测试装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112729762B (zh) * 2021-03-29 2021-07-02 中国空气动力研究与发展中心低速空气动力研究所 一种结冰栅格及云雾场均匀性的测量方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB125564A (en) * 1918-11-21 1919-04-24 Archibald Montgomery Low Improved Apparatus for Testing Aeroplanes.
US1804645A (en) * 1928-12-03 1931-05-12 Thomas C Rouse Holder for milk bottles and the like
DE632092C (de) * 1933-12-31 1936-07-02 Siemens Schuckertwerke Akt Ges Pruefanlage fuer Flugmotoren
US2380516A (en) * 1943-01-11 1945-07-31 Comet Model Airplane & Supply Wind tunnel balance

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB125564A (en) * 1918-11-21 1919-04-24 Archibald Montgomery Low Improved Apparatus for Testing Aeroplanes.
US1804645A (en) * 1928-12-03 1931-05-12 Thomas C Rouse Holder for milk bottles and the like
DE632092C (de) * 1933-12-31 1936-07-02 Siemens Schuckertwerke Akt Ges Pruefanlage fuer Flugmotoren
US2380516A (en) * 1943-01-11 1945-07-31 Comet Model Airplane & Supply Wind tunnel balance

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2995932A (en) * 1953-06-24 1961-08-15 Jr Everett J Hardgrave Device for measuring mach number
US2799160A (en) * 1955-03-28 1957-07-16 North American Aviation Inc Wind tunnel air flow control
US5235848A (en) * 1991-11-27 1993-08-17 The United States Of America As Represented By The Secretary Of The Navy Thruster test fixture
CN103486984A (zh) * 2013-10-12 2014-01-01 中国人民解放军63926部队 一种风洞内型面同轴度的检测方法
CN103486984B (zh) * 2013-10-12 2015-11-25 中国人民解放军63926部队 一种风洞内型面同轴度的检测方法
CN105571766A (zh) * 2014-10-11 2016-05-11 中国航空工业集团公司西安飞机设计研究所 一种风洞模型表面压力测试装置

Also Published As

Publication number Publication date
GB694150A (en) 1953-07-15
GB664055A (en) 1951-01-02
DE860558C (de) 1952-12-22
FR1117104A (fr) 1956-05-17
FR66701E (fr) 1957-08-19

Similar Documents

Publication Publication Date Title
US5880378A (en) Critical flow venturi with variable and continuous range
US2618972A (en) Testing apparatus for scale models of aerodynamic ducts
US2740295A (en) Temperature ratio measurement means
US4034604A (en) Apparatus for determining characteristics of turbo-powered airplane engine simulators
US2515069A (en) Wind tunnel
US2989846A (en) Shock wave sensing device
JP7421769B2 (ja) ダクト内圧力計測構造及び風洞試験装置
US3434679A (en) Simulated reaction engine model
Krull et al. Effect of Plug Design on Performance Characteristics of Convergent-Plug Exhaust Nozzles
Hromisin Aeroacoustic Characterization of Dual-Stream, Supersonic, Rectangular Exhaust Jets
Desikan et al. Effect of freestream–plume interaction on launch vehicle aerodynamics
US3602920A (en) Wind tunnel test section
Spalding The spread of turbulent flames confined in ducts
Harrington Performance of convergent and plug nozzles at Mach numbers from 0 to 1.97
Swihart et al. Effect of Afterbody Ejection Configurations on the Performance at Transonic Speeds of a Pylon-supported Nacelle Model Having a Hot-jet Exhaust
Greathouse et al. Performance characteristics of several divergent-shroud aircraft ejectors
Swihart Investigation at Transonic Speeds of a Fixed Divergent Ejector Installed in a Single-Engine Fighter Model
US3035439A (en) Hypersonic wind tunnel test section
Fleming Internal Performance of Several Types of Jet-exit Configurations for Supersonic Turbojet Aircraft
Berlin et al. Comparison of cold-gas simulations and rocket-launch data for constrictive launchers
US3011341A (en) Rocket excited wind tunnel
Trout et al. Internal Performance of Several Divergent-Shroud Ejector Nozzles with High Divergence Angles
Zvegintsev Determination of thrust characteristics of air-breathing jet engine
Matsumoto et al. Development of a subscale supersonic aeropropulsion wind tunnel
DAVIS A shock tube technique for producing subsonic, transonic, and supersonic flows with extremely high Reynolds numbers