Aerospace Science and Technology
Determination of a High-speed Centrifugal Pump's Stable Performance Range by Computational Fluid Dynamics

Ali Cheraghi; Reza Ebrahimi

Volume 16, Issue 1 , June 2023, , Pages 88-100

https://doi.org/10.22034/jast.2022.357423.1128

Abstract
  Feed pumps play a crucial role in the dynamics of hydraulic systems. The surge phenomenon is a common type of instability in pumps and compressors. This phenomenon is a systematic instability and is influenced by the dynamics of all components of a hydraulic system, including tank, valves, suction pipes, ...  Read More

Aerospace Science and Technology
Numerical study on enhancement of low speed axial compressor rotor performance under radial inlet distortion via DBD plasma actuators

Ali Khoshnejad; Reza Ebrahimi; Golamhosein Pouryossefi

Volume 15, Issue 1 , June 2022, , Pages 116-128

https://doi.org/10.22034/jast.2021.309899.1102

Abstract
  Aero-engine entrance conditions are not always ideal and, for various reasons, inlet distortion may occur and cause inlet blockage and reduction of compressor performance. The aim of this study was to numerically simulate the effects of plasma actuators on the enhancement of low-speed axial compressor ...  Read More

Aerospace Science and Technology
Investigation of Flow Separation Phenomenon for Supersonic Convergent–Divergent Nozzles

Omid Habibi; Reza Ebrahimi; Hassan Karimi Mazraeh Shahi

Volume 14, Issue 2 , October 2021, , Pages 141-151

Abstract
  The nozzle, an end-element of the propulsive process Cycle, represents a critical part of any aerospace vehicle. The task of accelerating and efficiently exhausting combusted and reactive gases according to the delivered thrust represents the main objective of the propulsion system design. Flow separation ...  Read More

Aerospace Science and Technology
Critical Cavitation Number Determination of a High-speed Centrifugal Pump by Numerical Simulation of a Two-phase Flow

Ali Cheraqi; Reza Ebrahimi

Volume 14, Issue 1 , June 2021, , Pages 91-102

https://doi.org/10.22034/jast.2021.299823.1090

Abstract
   This paper aims to present an investigation on determining the critical cavitation number of a high-speed centrifugal pump by computational fluid dynamics. In doing so, characteristic curves of the pump used in this study were obtained in the presence and absence of cavitation. The critical cavitation ...  Read More

Aerospace Science and Technology
Two-Phase CFD Modeling of Three-Dimensional Supercavitating Flows

Ali Cheraghi; Reza Ebrahimi

Volume 13, Issue 2 , October 2020, , Pages 53-60

https://doi.org/10.22034/jast.2021.127995

Abstract
   One of the most effective ways of high-speed motion in water is the motion in the supercavitation regime. This way provides the possibility to avoid considerable viscose resistance of boundary layer and consequently reach to very small drag coefficient which can be several times smaller than, that ...  Read More

Numerical Simulation of Scaling Effect on Bubble Dynamics in a Turbulent Flow around a Hydrofoil

Mehrzad Shams; Reza Ebrahimi

Volume 3, Issue 2 , June 2006, , Pages 67-75

Abstract
  A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure ...  Read More