List of Articles Behrooz Shahriari

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  1 - Investigating Cooling Effect with Compound Angle on the Combustion Chamber Wall Temperature
  Mohamad Reza Nazari Behrooz Shahriari Farhad Sebghatollahi
  Increasing the temperature of the turbine entrance gases increases the efficiency of the gas turbine cycle. Under these conditions, the combustion chamber wall temperature also increases, while there is no high temperature resistance alloy fitted with air motors. Theref More

  Increasing the temperature of the turbine entrance gases increases the efficiency of the gas turbine cycle. Under these conditions, the combustion chamber wall temperature also increases, while there is no high temperature resistance alloy fitted with air motors. Therefore, it is necessary to use cooling methods to reduce the wall temperature. In this study, the cooling effect with compound angles investigated on the combustion chamber wall temperature. The three-dimensional combustion chamber k-ɛ is modelled under the conditions of the input speed and the turbulence model in the ANSYS Fluent software. Inlet air is injected from the cooled holes to the mainstream with compound angle, where the cooling flow angle is constant with the 30° horizontally, and the lateral angle changes from Beta =0 up to Beta=60 degrees. The combustion chamber has two flat planes and two sloping plates, in which the arrangement of cooling holes is different. The results show that this method better distributes the cooling air on the wall surface and covers the space between the cooling holes, especially on flat plates. With this method, the number of cooling holes and the amount of air used to cooling can be reduced. Manuscript profile
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  2 - Stress and Displacement Analysis of First Molar Hollow Tooth during Dental Filling Operation using Three-Dimensional Finite Element Method
  M. R. Karamooz-Ravari B. Shahriari E. Seyfali
  the amount of rotten tooth that is come out of teeth is an important issue in dental filling because of its effects on strength of teeth. The main goal of this study is to determine a criterion for the amount of rotten tooth which can be brought out. To do so, first, a More

  the amount of rotten tooth that is come out of teeth is an important issue in dental filling because of its effects on strength of teeth. The main goal of this study is to determine a criterion for the amount of rotten tooth which can be brought out. To do so, first, a three-dimensional finite element model of the complex shape of Right First Molar Mandibular has been established. Then, cylindrical holes with different values of height and diameter (diameter of holes from 3 mm to 8 mm and height of 3 mm to 5.9 mm) is created on the cusp of the tooth. A uniform pressure (from 10 Pa to 10 kPa) is applied around the tooth resembling the belt which is utilized in reality. According to the obtained displacement and stress contours, the diameter of tooth hole can be increased up to 7 mm for pressures under 10 Pa while for higher pressures, the diameter of tooth hole can just be increased up to 6 mm. In addition, due to sudden increase in stress at a pressure of 10 kPa, increasing the value of pressure to higher values is not recommended. Manuscript profile
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  3 - Vibration Sensitivity Analysis of Nano-mechanical Piezo-Laminated Beams with Consideration of Size Effects
  mostafa nazemizadeh Firooz Bakhtiari-Nejad Behrooz Shahriari
  10.30495/admt.2020.1899033.1196
  The presented article investigates vibration sensitivity analysis of Nano-mechanical piezo-laminated beams with consideration of size effects. To do this, the vibration governing equation of the stepped Nano-mechanical piezo-laminated beam is firstly derived by implemen More

  The presented article investigates vibration sensitivity analysis of Nano-mechanical piezo-laminated beams with consideration of size effects. To do this, the vibration governing equation of the stepped Nano-mechanical piezo-laminated beam is firstly derived by implementation of the nonlocal elasticity theory. The nonlocal formulation is considered for both of the beam and the piezoelectric layer and the obtained equation is solved analytically. Moreover, there is a need to recognize the importance and relative effects of the beam parameters on the natural frequencies and resonant amplitudes of the nonlocal beam. Therefore, the Sobol sensitivity analysis is utilized to investigate the relative effects of geometrical and the nonlocal parameters on the natural frequencies and the resonant amplitude of the nanobeam. The obtained results show that the length and the thickness of the piezoelectric layer have prominent effects on the vibration characteristics of the beam. Moreover, it is indicated that nonlocal parameter effect on the resonant amplitudes is more than resonant frequency. Also, the effect of the nonlocal term is more important at higher modes of vibration. Therefore, the nonlocal size effects cannot be ignored in vibration analysis of the nanobeam especially at higher modes. Manuscript profile
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  4 - Effect of Aerodynamic Blade Change of Two-Stage Axial Subsonic Turbine on Design Point
  Mahmood Adami Behrooz Shahriari Ali Zamani Gharaghoushi
  In this research for reducing the effect of losses and increasing the efficiency, the bowing in the rotor and stator blades is used. In one mode rotor blades are curved and in other one, stator blades are curved. The amount of rotor loss, due to changes in the thickness More

  In this research for reducing the effect of losses and increasing the efficiency, the bowing in the rotor and stator blades is used. In one mode rotor blades are curved and in other one, stator blades are curved. The amount of rotor loss, due to changes in the thickness of the trailing edge and operating rotational speed, have been investigated. To confirm the accuracy of the results, a turbine stage whose experimental results are available is modeled and numerical results have been compared with experimental results that indicate acceptable compliance. The turbulence model k-w-SST is used to solve turbulent flow. The positive bowing, creates a pressure gradient from the two ends of the blade towards the center of the blade, which leads to the directing of the secondary flows toward the center of the blade. This reduces the losses in the two ends of the blade and increases the loss in the middle part of the blade. Increasing the thickness of the trailing edge, as well as increasing the turbine’s operating rotational speed, will increase the loss. The curved rotor increases the efficiency and mass flow and power by 0.4% and 0.5% and 0.8% respectively and the curved nozzle reduces the efficiency and power by 0.3% and 4.9% but increases the mass flow by 0.2%. It also increases the thickness of the trailing edge of the first rotor from 0.2mm to 0.9mm at 24000 rotational speed and increases the total loss by about 35%. Manuscript profile
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  5 - Weld Distortion and Residual Stresses in Aluminum Hollow Section T-Joint
  Asghar Mahdian Arash Babamiri Behrooz Shahriari
  10.30486/admt.2022.1934601.1296
  Welding is known as one of the most popular attaching methods for different hollow section components. However, local concentrated heating, distortion, and residual stresses at welded joints are unavoidable. In this article, the welding simulation for rectangular hollow More

  Welding is known as one of the most popular attaching methods for different hollow section components. However, local concentrated heating, distortion, and residual stresses at welded joints are unavoidable. In this article, the welding simulation for rectangular hollow (RHS) sections for the front axle carrier of the new BMW series-7 is discussed and weld distortion and residual stresses in its aluminum T-joint for one proposed sequence are investigated. Comparisons of the results of this paper for this recommended sequence with experimental results in some references show good agreement and indicate that characteristics of the welding distortions are fully forecasted. In the following of this paper, the Finite Element Method (FEM) is used to offer a better sequence with smaller weld distortion and residual stresses. Weld distortion and residual stresses are highly influenced by welding strategy. In the proposed strategy, the needed time to perform the welding process decreased, and the total weld distortion and residual stresses decreased by 24% and 4%, respectively. Manuscript profile
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  6 - Vibration Analysis of Rotating Disk Carrying Annular Concentrated Masses in Turbo-pump System
  Behrooz Shahriari Mostafa Nazemizadeh A. M. Shirvani
  10.30486/admt.2023.697496
  Vibration analysis of rotating disks is one of the most important problems in turbomachines. In this study, a new method has been presented which analyzed the radial vibration of a turbo-pump rotating disk carrying two annular concentrated masses located on the disk and More

  Vibration analysis of rotating disks is one of the most important problems in turbomachines. In this study, a new method has been presented which analyzed the radial vibration of a turbo-pump rotating disk carrying two annular concentrated masses located on the disk and at its end. Natural frequencies have been calculated in different rotating speeds; then results have been compared with each other. The effects of concentrated masses position and intensity on natural frequencies have been investigated. The results show that concentrated masses always have been decreased the value of first natural frequency, but in the case of second and third natural frequencies, depending on the mass concentration magnitude and its position, the magnitude of natural frequency has been increased or decreased. The vibration of the rotating disk without considering the concentrated mass, was examined. Then the resulting solution was generalized for two connected disks in internal concentrated mass location. The effect of concentrated masses, one on the disk body and the other on the outside of the disk, is considered as boundary conditions in the two disk Equations. The results show that increasing in angular velocity of rotating disk reduces the natural frequency. Concentrated masses always reduce the first natural frequency. At the second and third natural frequencies, concentrated masses may increase or decrease the natural frequency, which depends on the value and position of concentrated mass. Concentrated mass has the most impact when it is in a position that has the most radial displacement. Manuscript profile
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  7 - A Quasi-Analytical Method Algorithm Development in Redesigning the Geometry and Structural Analysis of An Aircraft Propeller and Comparing with the Finite Element Method
  Behrooz Shahriari Hassan Izanlo Nedasadat  Seddighi
  The aircraft propeller is effective in the performance of the aircraft propulsion system and must have acceptable structural strength. The complex aerodynamic geometry of the propeller makes its analysis more difficult. In this study, dynamic and aerodynamic stresses ar More

  The aircraft propeller is effective in the performance of the aircraft propulsion system and must have acceptable structural strength. The complex aerodynamic geometry of the propeller makes its analysis more difficult. In this study, dynamic and aerodynamic stresses are calculated using the Finite Element Method (FEM). A structural analysis algorithm based on the quasi-analytical method is developed to evaluate the finite element analysis. In this regard, first, an algorithm is developed to redesign the propeller which performs in a way that by checking the dimensions, the geometry of the quasi-propeller is determined with the same mass and the coordinates of the center of mass. Then, different algorithms are developed to calculate the distribution of mass, moment of inertia, and the cross-section of the quasi-blade geometry. The calculation algorithms of rotational dynamic and aerodynamic stress distribution are developed. The results show that the FEM and the quasi-analytical method are well matched. In this study, the force equivalent to the thrust and the opposite force to the propeller rotation are placed instead of the aerodynamic pressure distribution. The comparison of the results obtained from the quasi-analytical method and the FEM indicates that the overall maximum stress of the system occurs at the root of the propeller and the maximum net stress due to aerodynamic forces occurs in the middle of the propeller geometry. According to the results, the rotational dynamic stress is much higher than the aerodynamic stress. It is also shown that the aerodynamic stress reduces the overall stress of the system. Manuscript profile