This page exhibits some of the projects I have been working on during my career as a mechanical engineer and a researcher in the field of computational fluid dynamics. If you would like to know more, please do not hesitate to contact me.
A Flow Solver Development
HOMA (High-Order Multilevel Adaptive) solver is a continuous finite-element framework for the solution of RANS equations on unstructured grids. High-order discretizations, robust and scalable preconditioning techniques, and multigrid capabilities are important features of this flow solver. A major goal in development of HOMA is enhancing deep convergence capabilities through development of strong solvers. In this code, the time integration is fully implicit, and automatic differentiation is used for the exact linearization. For non-linear advancements, two principle algorithms are used: (1) an optimized Newton-Krylov method based on the Pseudo-Transient Continuation (PTC), and (2) a spectral multigrid algorithm based on the full approximation scheme (FAS). For linear preconditioning, adaptive block ILU smoothing (ILUB), matrix-based implicit line relaxation, ILU(k), and Restrictive Additive Schwarz (RAS) methods have been built into the code.
For more details, please see:
AIAA Paper 2019-0101,
AIAA Paper 2017-0517,
AIAA Paper 2017-4275, and
Three-Dimensional Multiblock Structured Grid for a Turbofan with Highly Twisted Rotor Blades
A Structured Grid Generation using Pointwise
While modern automated unstructured grid technologies are much easier to apply on the complex geometries, many CFD researchers in the field of turbomachinery prefer to utilize the structured grids due to indispensable advantages that these grids provide when the flow patterns are predictable. This project, which was carried at the UTC SimCenter, utilized an effective topology to generate a multiblock structured grid for an SDT-R4 turbofan which includes highly twisted blades in the rotor. The essence of the work was to use a combination of O-type and H-type topologies such that the boundary layer on the blades are resolved properly and the grid between the blades follow the expected flow paths. The grid was generated for the entire geometry including the rotor, stator, and around the shroud. The grid was generated such that the periodic boundary conditions could be applied between the rotor and stator blades.
High-Capacity Seawater Intake Centrifugal Pump
(Capacity=8000 m3/hr, Head=87 m, N=740 rpm)
A CAE Project from Scratch to Construction
This project was carried out in the Iran Industrial Pumps (IIP) company for Mobin Petrochemical Complex (in Iran) to replace an existing pump made by Hitachi. Following the completion of the design, a prototype (with the scale of 0.35) was constructed and tested which resulted in an excellent agreement with the design goals. In this project, the efficiency of the pump improved by 2 percent. Finally, the full-size pump was constructed. As the head designer and CFD engineer, my responsibilities included the hydraulic design of the pump, collaboration with solid mechanical engineers to design the mechanical components, supervising the assembly of the components, and approval of the final shop drawings.
Hydraulic design and CFD by Behzad R. Ahrabi
Mechanical design and analysis by Farzad Sadr
High-Pressure Multi-Stage Centrifugal Pump
(Capacity=420 m3/hr, Head=475 m, N=1480 rpm)
An Optimization Project
This project was carried out in the Iran industrial pumps (IIP) company for wastewater disposal company of Khuzestan. A high pressure four stage pump was reverse-engineered and optimized. My responsibilities included measuring all the components of the pump, geometry modeling for CFD, improvement of the impellers, co-operation with the mechanical design team to redesign all the mechanical parts, supervising the assembly of the components, and approval of the final shop drawings. In this project, besides the hydraulic improvements, we succeeded to decrease the weight of the pump significantly.
Hydraulic optimization by Behzad R. Ahrabi
Mechanical optimization by Farzad Sadr