The defense of the master’s student Ayat Abbas Kazem took place in the Department of Biomedical Engineering on Wednesday, 27/8/2025, regarding her thesis entitled:

“Hemodynamic Analysis of Mechanical Aortic Valve using Computational Fluid Dynamics”

The defense committee consisted of:

• Chairman: Prof. Dr. Sadiq Jaafar Abbas

• Member: Prof. Dr. Bassam Maddah Hassan

• Member: Asst. Prof. Dr. Mais Uday Abdulrasool

The thesis was supervised by:

• Asst. Prof. Dr. Samar Ali Jaber – College of Engineering / Al-Nahrain University

• Consultant Dr. Ahmed Abdulraouf Ammar – Ibn Al-Bitar Specialized Center for Cardiac Surgery

The thesis was scientifically evaluated by:

• First Scientific Reviewer: Prof. Dr. Hussam Kazem Abdulameer – Al-Khwarizmi College of Engineering / University of Baghdad

• Second Scientific Reviewer: Asst. Prof. Dr. Farhan Ahmed Khumais – College of Engineering / Al-Nahrain University

The thesis was linguistically reviewed by:

• Asst. Prof. Dr. Safa Laith Kailan – College of Engineering / Al-Nahrain University

Study Objective:

This study aims to analyze the hemodynamics of blood flow through a bileaflet mechanical heart valve (St. Jude Medical) using Computational Fluid Dynamics (CFD), with experimental validation through a test rig designed to simulate the pumping action of the human heart.

Methodology:

• A simplified 3D model including the valve, aortic sinuses, ascending aorta, and part of the left ventricle.

• Computer simulations using ANSYS Fluent 2022R1 to study the effect of leaflet motion on flow variables.

• Mesh sensitivity study by comparing three element sizes (2 mm, 1 mm, and 0.5 mm).

• A low-cost experimental setup built with a pump driven by a servo motor controlled by an Arduino Uno, along with a blood-mimicking fluid (BMF) prepared to replicate human blood viscosity.

Results:

• The highest wall shear stresses (WSS) appeared at full valve closure just before the cardiac cycle begins, especially on the upper surfaces and trailing edges of the valve leaflets.

• During partial valve opening, regions of elevated stress emerged near the central and side orifices.

• Pressure distribution showed that total pressure peaked at full closure and at 75% valve opening, while dynamic pressure increased near leaflet tips due to flow disturbances.

• The finest mesh (0.5 mm) achieved the best numerical accuracy with Y⁺ = 4.3, suitable for near-wall turbulence modeling.

Conclusion:

This study confirms that leaflet motion and mesh resolution are critical factors in simulating blood behavior around mechanical valves. Combining computational simulation with experimental validation provides a strong framework for future studies, including the impact of coronary arteries and fluid–structure interaction (FSI) modeling.

The thesis was accepted as it fulfills the requirements for the Master’s Degree in Biomedical Engineering.