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Experimental Investigation of the Effect of Nozzle Exit Flow on the Aerodynamic Behavior at Transonic Speed

Ayati, Hossein | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48552 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Farahani, Mohammad
  7. Abstract:
  8. The aim of this investigation is the experimental study of nozzle exhaust jet flow effects on aerodynamic behavior of an air vehicle at transonic speeds. For this sake, a secondary jet injection is used by the ejector into test model. The ejector total pressure for jet injection varies between 0 (jet off) to 4 bar for simulating nozzle exhaust jet flow and supplying intake’s required mass flow rate. All tests were conducted at QRC Trisonic wind tunnel and at Mach number of 0.5 to 0.85 and angles of -4 to 6 deg. The aerodynamic force and pressure results were recorded in order to analyze the exhaust jet flow. This study revealed that the aerial vehicle drag becomes bigger than its free flight value if cold jet is employed for simulation of the nozzle exhaust hot jet flow. Therefore a practical method of using nozzle afterbody drag on an aircraft model in the wind tunnel with an ambient temperature (cold) jet exhaust flow to predict afterbody drag with a hot jet exhaust typical of the full scale flight vehicle is presented. Furthermore, experimental results showed that the secondary jet injection decreases the air vehicle drag coefficient. Further, as the mass flow rate of secondary jet flow increases, the drag coefficient reduction will be increased. As Mach number increases, the drag coefficient difference between jet off and jet on conditions becomes smaller. For verification of the flow separation effect on drag coefficient, the closed nozzle is analyzed and compared with previous results
  9. Keywords:
  10. Ejector ; Intake System ; Drag Coefficient ; Jet Plume Blockage ; Jet Entrainment ; Hot Jet ; Cold Jet

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