WO2020141316A1 - Améliorations dans ou concernant l'angle de détection d'attaque - Google Patents

Améliorations dans ou concernant l'angle de détection d'attaque Download PDF

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Publication number
WO2020141316A1
WO2020141316A1 PCT/GB2019/053662 GB2019053662W WO2020141316A1 WO 2020141316 A1 WO2020141316 A1 WO 2020141316A1 GB 2019053662 W GB2019053662 W GB 2019053662W WO 2020141316 A1 WO2020141316 A1 WO 2020141316A1
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
aoa
chord
local
sensing arrangement
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.)
Ceased
Application number
PCT/GB2019/053662
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English (en)
Inventor
Michael Alex BROMFIELD
Thomas Oliver MILWARD
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.)
Coventry University
Original Assignee
Coventry University
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 Coventry University filed Critical Coventry University
Publication of WO2020141316A1 publication Critical patent/WO2020141316A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • G01M9/065—Measuring arrangements specially adapted for aerodynamic testing dealing with flow

Definitions

  • the method may then include the step of comparing the measured pressure distribution to one or more stored pressured distributions so as to determine the AOA.
  • the pressure distributions may be stored in a lookup table.
  • the step of comparing may be performed by the processing unit.
  • the AOA may be calculated by the processing unit using the results of the comparison.
  • the stored pressure distributions may be generated by use of a suitable theoretical model and/or by calibration testing.
  • a suitable theoretical model is a Vortex Lattice Model (VLM).
  • VLM Vortex Lattice Model
  • advanced computational fluid dynamics using Reynolds-averaged Navier-Stokes equations could be used to generate pressure distributions.
  • the local pressure coefficient C p may be calculated from a relation such as: where P ⁇ is the freestream static fluid pressure, V ⁇ is the freestream dynamic fluid velocity and p ⁇ is the freestream fluid density.
  • the method may include the additional steps of measuring one or more of: freestream static fluid pressure P ⁇ , freestream dynamic fluid velocity V ⁇ and/or freestream fluid density p ⁇ .
  • the sensing arrangement may comprise dedicated sensors for measuring such characteristics.
  • the sensing arrangement may be connected to external sensors for sensing such characteristics.
  • the local pressure co-efficient can be easily calculated as it is derived from sensors that are already common on current aircraft.
  • the airfoil is a wing or tail plane of an aircraft. Additionally or alternatively, the airfoil may be a fixed sensing vane of an aircraft. Such a sensing vane may project from any suitable position on the aircraft.
  • the multiple sets of sensors may be provided on different airfoils. This can provide local AOA measurements for different airfoils of an aircraft.
  • the present invention is thus capable of determining a potentially dangerous AOA on a single wing of an aircraft.
  • the FMS may perform local AOA analysis.
  • the local AOA analysis may be performed using the chord pressure co-efficient.
  • the FMS may calculate a local AOA for each set of chord-wise pressure sensors.
  • the FMS may calculate differences between the local AOA at different span-wise locations on an airfoil.
  • the FMS may compare these differences to expected differences or a range of safe difference values.
  • the FMS may compare the measured local AOA to a range of safe local AOA values.
  • the local AOA analysis results may provide improved stall warnings.
  • the stall warnings may be in relation to common loss of control in-flight (LOC-I) scenarios. Stall warnings may be provided during asymmetric flight conditions. Stall warnings may be output by any suitable sensory means.
  • LOC-I loss of control in-flight
  • Figure 1 is a schematic illustration of an airfoil defining the angle of attack
  • Figure 7 is a series of experimental results showing the chord pressure co efficient against AOA for chords at different span-wise locations on an airfoil.
  • Figure 8 is the data in figure 7 integrated span-wise to show the final global pressure co-efficient against AOA for an airfoil.
  • an airfoil 10 for example a wing of an aircraft, is illustrated in cross-section.
  • the airfoil 10 is of the common NACA 2412 profile.
  • the airfoil has a leading edge 11, a trailing edge 12, an upper surface 13 and a lower surface 14.
  • a chord line 15 is defined as the axis between the leading edge 11 and trailing edge 12 perpendicular to the span of the airfoil 10.
  • chord pressure co-efficient from each chord line is then integrated across the span of the airfoil 10 to generate the final global pressure co-efficient.
  • the global pressure co-efficient, C PclobaV is given by: where b is the span length.
  • the global pressure co-efficient against AOA for the airfoil 10 is shown in figure 8. As shown in figure 8, the global pressure co-efficient provides a more robust measure of the AOA and facilitates accurate measurements even at high AOA that are not accessible to traditional measurement systems.
  • the global pressure co-efficient can also be calculated with a double integration, where the formula for the chord pressure co-efficient is substituted into the above formula for the global pressure co-efficient.
  • the pressure co-efficient is measured at two known AOA values. Aa Body and AC Pclobal are then calculated using the respective change in a Body and Cp Global between the two calibration points.
  • the global pressure co-efficient can also be used to calculate the lift co-efficient of the airfoil. The lift co-efficient is approximately equal to the global pressure co-efficient.
  • the chord pressure co-efficient is used to calculate a local AOA.
  • a a Local AOA is the chord pressure co-efficient
  • the display interfaces 51 can then display the calculated AOA.
  • the FMS 50 compares the current AOA to a range of safe values for the AOA. If the AOA is not in the range of safe values, the FMS 50 may output an alarm. The FMS 50 may output an alarm using the display interfaces 51 and/or alarm outputs 52.
  • the FMS 50 also performs local AOA analysis. During local AOA analysis, the FMS 50 receives the chord pressure co-efficient for each set of pressure sensors 22 from the processing unit 30 of each AOA sensing arrangement 100. The FMS 50 then calculates a local AOA for each set of pressure sensors 22.
  • the FMS 50 is also operable to calculate the lift co efficient of the wing 201.
  • the lift co-efficient can be calculated using the global pressure co-efficient as described previously.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un procédé et un appareil de détection d'angle d'attaque (AOA) nécessitant une série de capteurs de pression montés en surface (21) disposés le long d'une ligne de corde d'un profil aérodynamique (10). Une unité de traitement (30) peut être utilisée pour calculer un coefficient de pression locale C p pour chaque capteur (21). Ensuite, l'unité de traitement (30) réalise une intégration sur des signaux indicatifs d'une pression locale le long de la ligne de corde pour permettre la détermination d'un coefficient de pression locale et donc de l'angle d'attaque (AOA) local. Selon d'autres modes de réalisation, une pluralité d'ensembles (22) de capteurs (21) sont prévus, chaque ensemble (22) sur une ligne de corde différente (10). Selon de tels modes de réalisation, un coefficient de pression globale peut également être calculée à la fois avec une intégration dans le sens de la corde et dans le sens de l'envergure.
PCT/GB2019/053662 2019-01-04 2019-12-20 Améliorations dans ou concernant l'angle de détection d'attaque Ceased WO2020141316A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201900117 2019-01-04
GB1900117.1 2019-01-04

Publications (1)

Publication Number Publication Date
WO2020141316A1 true WO2020141316A1 (fr) 2020-07-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2019/053662 Ceased WO2020141316A1 (fr) 2019-01-04 2019-12-20 Améliorations dans ou concernant l'angle de détection d'attaque

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WO (1) WO2020141316A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113970400A (zh) * 2021-10-22 2022-01-25 中国汽车工程研究院股份有限公司 一种基于翼型结构的多精度、大量程气流偏角测量装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2254880A1 (fr) * 1996-05-13 1997-11-20 Redwood Aircraft Corporation Avion a fuselage/ailles porteurs avec une partie avant elliptique
US20090018703A1 (en) * 2007-05-09 2009-01-15 Mangalam Arun S System and Method for Control of Aeroelasticity Effects
US20100274444A1 (en) * 2008-01-15 2010-10-28 Walton Ross Williamson Methodology for Autonomous Navigation and Control of a Tethered Drogue

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2254880A1 (fr) * 1996-05-13 1997-11-20 Redwood Aircraft Corporation Avion a fuselage/ailles porteurs avec une partie avant elliptique
US20090018703A1 (en) * 2007-05-09 2009-01-15 Mangalam Arun S System and Method for Control of Aeroelasticity Effects
US20100274444A1 (en) * 2008-01-15 2010-10-28 Walton Ross Williamson Methodology for Autonomous Navigation and Control of a Tethered Drogue

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113970400A (zh) * 2021-10-22 2022-01-25 中国汽车工程研究院股份有限公司 一种基于翼型结构的多精度、大量程气流偏角测量装置

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