The Effect of Blade Surface Roughness on the Transonic 4-stage Axial Compressor Performance
Seyyed Meysam
Sajjadi
author
Abdollah
Asadollahi Ghohieh
author
text
article
2012
per
In this research, An investigation is done to understand the effects of blades surface roughness on the Transonic 4-stageAxial compressor performance parameters. A CFD code, which solves the Reynolds-averaged Navier–Stokes equations, was used to simulate the complicated 3D flow field of the Axial compressor. Numerical results was validated against experimental data of the Axial compressor performance curves. Numerical data showed good agreement with experimental data. Then, the effects of blades surface roughness on the Axial compressor performance parameters at design point was analyzed. Results show that blades surface roughness leads to increase boundary layers and pressure loss and decrease the efficiency and pressure ratio. So efficiency reduction goes up comparing with pressure ratio in the compressor.
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
1
10
https://www.joae.ir/article_120432_9e74ea19266f1a2442b28004a16b8c6e.pdf
Analytical and Experimental Studies of Cyclic Thermal Shock Effects on Nonlinear Behavior of Composite Laminates
Ahmadreza
Ghasemi
author
Rasoul
Baghersad
author
text
article
2012
per
The elastic properties and breaking strength do not remain constant and vary nonlinearly under cyclic thermal loading. The variation is larger and indeed more important in the case of composites as compared to isotropic materials. The variations of strength and elasticity modulus may be represented as a function of the number of thermal shocks, i.e. the difference among the temperatures exerted in these cycles and a reference temperature; which are measured experimentally. A new experimental device is designed and manufactured which can be conveniently used to apply thermal loads with different temperature on composite laminates. Subsequently, orthotropic glass-epoxy composites made by hand lay-up are tested under cyclic thermal loading using this apparatus. The variation of the elasticity modulus and breaking stress of the samples are measured before and after exerting defined number of thermal load cycles. As a result a convenient mathematical model is proposed whose predictions are in agreement with the experimental measurement. Finally, the obtained equations are used as the representative of material behavior in an analytical study of laminate fracture. The result show that nonlinear behavior of the composite under the thermal shock affects the breaking strength.
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
1
16
https://www.joae.ir/article_120433_499cb3205247927ed0953ff2cdc4de09.pdf
The Study of Wing Damage Effect on Airplane Performance and Flight Dynamics
Davoud
Asadi
author
Mehdi
Sabzehparvar
author
Heydarali
Talebi
author
Hamed
Abbasi
author
text
article
2012
per
While an aircraft experiences a damage, system parameters severely change depending on the damage location and quantity. The autopilot is not able to maintain the airplane control in case of considerable damage. A preliminary requirement for recoverability and survivability of an aircraft after the damage is a better understanding of its performance and flight envelope. In this paper, wing damaged airplane maneuvering flight envelope and stability properties inside the maneuvering flight envelope are investigated for different wing damages and at different altitudes. In addition, eigenvector analysis is utilized to demonstrate the effect of damage on motion modes, handling quality, and longitudinal and lateral-directional coupling. The overall above analysis provides a comprehensive understanding of the wing damage effect on airplane performance and dynamics that is essential for flight durability and safe landing.
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
17
33
https://www.joae.ir/article_120434_ee34489cc3f1abbcad3918650ed153e0.pdf
Non
Farajollah
Valipour
کارشناس ارشد مدیریت صنعتی - دانشگاه تهران
author
Amirhossein
Deziyanian
کارشناس ارشد مدیریت سیستم و بهره وری
author
Kourosh
Emami Saleh
author
Shahla
Naghipour
author
text
article
2012
per
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
35
48
https://www.joae.ir/article_120768_19ed181a91655566bc0cedff017681eb.pdf
Investigation of Unsteady Parameters Effects on Aerodynamic Coefficients of Pitching Airfoil Using Coarse Grid CFD
Ali
Heydari
author
Mahmoud
Pasandideh Fard
author
Majid
Malek Jafarian
author
text
article
2012
per
In this article, the effects of unsteady parameters including mean angle of attack, oscillation amplitude, reduced frequency and pitching axis position on aerodynamic coefficients of a pitching airfoil are studied. The numerical method is described as Coarse Grid CFD (CGCFD) in which the Euler equations are solved using a coarse grid and no slip boundary conditions with compressible surface vorticity confinement technique. The required unsteady time for this method is significantly lower compared to that of the full Navier-Stokes equations with even a simple one equation turbulence model. It is found that the computational time for one oscillation loop is reduced more than fifty times. In addition, a multi zone adaptive spring network is applied to simulate the moving boundary which further reduces the computational time. The obtained numerical predictions are in good agreement with experimental data. In this paper, first, the results are compared with the experiments in two mean angles of attack with specific oscillation amplitude and reduced frequency. Then, the effect of these parameters and pitching axis positions on aerodynamic coefficients of pitching NACA0015 airfoil is investigated. It is observed that moving the pitching axis position to the right or left outside and distancing from trailing edge or leading edge have inverse effects on thickness of the hysteresis loops, the maximum, minimum, and average lift and drag coefficients. Further, increasing the reduced frequency results in a reduction of the lift hysteresis loop slope and the maximum lift and drag coefficients.
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
49
66
https://www.joae.ir/article_120968_a11d80342c563932f01182a5b2ec65e8.pdf
Experimental investigation of air flow velocity distribution and its turbulences in an octagonal to square diffuser
Mohammad Ali
Ardekani
author
Seyyed Morteza
Parpanji
author
text
article
2012
per
An octagonal to square diffuser is an important section of the vertical wind tunnel, which has been designed for sky-diving operations. To determine the actual pressure drop of the diffuser, the velocity distribution should be measured. In addition, flow separation can be investigated by velocity distribution. In this research, a 7.8 % model of the original diffuser has been constructed, and velocity distribution and turbulence intensity of airflow have been measured using hot-wire Anemometer. The results of velocity distribution and turbulence intensity showed no flow separation in the tested diffuser. The error associated with pressure drop estimation is significant in the absence of the velocity distribution effects
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
67
76
https://www.joae.ir/article_120969_f35a7cba142608c0c61ca0e88f8c7e5f.pdf
Designing a flight database for increasing aviation safety
Aziz
Nasirzadeh
author
Mohammadreza
Marvinam
author
Mohammad
Bakhshandeh
author
text
article
2012
per
Aviation industry in accordance with its development and use of sophisticated techniques and technology has faced many repeated air accidents. Any event that happened in the past can be used as a historical experience in order to prevent similar disasters in the future. In other word, evaluating and analyzing the past events can be used to identify the potential factors which cause the air accidents. In addition, exact investigation of these factors could be a solution for reducing these accidents. In order to be much closer to this goal, comprehensive database should be designed and also be accessible for administrators, technical managers and the strategic and operational levels to maintain the readiness and minimize damage to the aviation industry. This study is a theoretical research in the field of air accidents to present a comprehensive model of flight database and operation in order to prevent the occurrence of similar accidents. The population of the research consists of aviation accident experts in aviation industry. Non probability sampling method is used to determine the sample of this research. Data collection is done by in-person questionnaire and archival data. The research method is field- descriptive. The results show the importance of database design to increase the flights’ safety factors of aviation industry.
Journal of Aeronautical Engineering
Shahid Sattari Aeronautical University of Science and Technology-Iranian Aerospace Society
Director-in-Charge:
Dr. Akbar Cheraqi
Editor-in-Chief:
Dr. Farhad Javidrad
Associate Editor:
Dr. Vahid Khalafi
Website Manager:
Amir Ehsan Zamanian
Eng. Nima Mansour Lakouraj
English Text Editor:
Dr. Roohollah Maleki
17359449
14
v.
2
no.
2012
77
87
https://www.joae.ir/article_120970_85d46edd4b902c9dac5ed1679918b321.pdf