Department of Mechanical Engineering

University of Technology

Oral Defense - MS Degree Thesis

Titled” "Experimental and Numerical Study of Convection Heat Transfer Inside a Triangular Channel Filled with Porous Media at Constant Heat Flux Boundary Condition"

By:  Sabah Raad Mahdi Saleh

Members of the examining committee:

Chair:

Asst. Prof. Dr. Lama Fadel Ali

Members:

Asst. Prof. Dr. Qusai Jihad Abdel Ghafour

Dr. Yasmine Hamid Abdel Hussein

Supervision By:

Dr. Suhad Abdul Hamid Rashid

Mr. Sabah Raad Mahdi Saleh has been debated his thesis titled" A practical and numerical study of heat transfer by forced convection inside a triangular duct filled with porous material under a constant heat flux as a boundary condition". The main objectives of this study are to study the effect of the overall heat transfer coefficient when using glass balls with a diameter (5 mm and 12 mm) as a porous medium inside a triangular channel and that the porosity inside the channel was (0.468 and 0.616) respectively for the Reynolds number range from (3165 to 10915 at a constant heat flux and that the fluid used is air. Furthermore, to study the effect of changing the angle of rotation of the channel on the same axis (from zero to 30 degrees and 60 degrees).

The researcher concluded that the usage of glass balls as a porous medium boosts the overall heat transfer coefficient. Consequently, the overall heat transfer coefficient at the Reynolds number (10915) is around 90.2% for the balls at a diameter equal to 5 mm, and 88.1% for balls at a diameter of 12 mm when compared with the channel that is not filled with porous medium. Further, the effect of changing the channel rotation angle is very slight at the same Reynolds number.

The researcher recommended that the usage of glass balls as a porous medium works to enhance the performance of heat transfer via the triangular channel, that affects increasing the pressure difference on the two ends of the channel, as well as the increase in the coefficient of friction. Extra, the effectiveness coefficient of the entire system was at porosity (0.616) better than at porosity (0.468).

Best wishes to our student Mr. Sabah Raad Mahdi Saleh

A patent for A group of Mechanical Engineering Department Faculty Members 

Titled “Design and Control of an Intelligent Artificial Knee Joint Using an Electromechanical Linear Actuator with a Servo Cylinder”

Inventor's name and address:

• Shaima Helal Kamel

 University of Technology / Department of Mechanical Engineering

• Prof. Dr. Mohsen Nouri Hamza

University of Technology / Department of Mechanical Engineering

• Prof. Dr. Qassem Abbas Attia

   University of Technology / Department of Mechanical Engineering

• Saad Abdel Aziz Abdel Latif,

    Iraqi University / College of Medicine

About the Patent Prototype:

 The knee prosthesis is the main component of the above-knee amputee prosthesis as it replaces the functional joint. The loss of a limb has a destructive influence on any person, especially if it is the lower limb because it is very important for human movement. A lower limb prosthesis has been developed to help amputees restore motor functions such as walking, standing, and going up and downstairs.

The present smart prosthesis is equipped with sensors, actuators, controls, and a mechanical structure that simulates the function of a natural limb and reduces the metabolic energy of above-knee amputees, allowing them to achieve various effective daily movements.

The newly designed smart artificial knee joint is distinguished by its special and very high efficiency for both mechanical and electronic aspects, the new design of the smart artificial knee joint has been proven to be 100% successful as a passive mechanical movement and electronic movement. Further, It operates when power is cut from the source, and it has the ability to move very smoothly and raise the leg highly, where achieves great success in the swing phase and achieves deceleration and acceleration with very high accuracy.

It is characterized by moving at different speeds slow, medium, and high. Several important aspects have also been achieved, including reducing the total cost of smart prosthetics by $2,895, while the price of smart prosthetics around the world is $30,000 to $100,000. The above-knee amputee weighs 110 kg and provides an intelligent knee joint flexion angle of 120 degrees. The design is according to the natural standard dimensions of the knee and leg joints of the human body, and it bears a force of 5000 Newton, which is a standard force to bear the performance of effective daily movements with high accuracy. It meets the requirements of Iraqi society and the wide world for smart prosthetic limbs.

Department of Mechanical Engineering

University of Technology

Final Defense of PH. D Degree Dissertation

Titled “Characterization of Porous Functionally Graded Materials in Vibration and Buckling of Sandwich Plates”

By:  Imad Kazem Najm

Members of the examining committee:

Chair:

          Prof. Dr. Ibtihal Abdel Razzaq Mahmoud

 Members:

          Prof. Dr. Bashar Awaid Badawi

Prof. Dr. Mohsen Abdullah Abdul-Hussein

Asst. Prof. Dr. Abdulsattar J. M. Hassan

Asst. Prof. Mohsen Nouri Hamza

By Supervision:

Asst. Prof. Dr. Sadiq Hussein Bakhi

Asst. Prof. Dr. Muhannad Lafta Shalaka

Mr. Imad Kazem Najm discussed his dissertation, which aimed to study the properties of composite panels manufactured from functionally graded materials that include pores changing in a specific direction of the structure. Where a mathematical model has been proposed to describe the free vibration, buckling, and bending based on the traditional plate theory (CPT) for composite panels. The outcomes of this work can be applied to the simulation of aircraft wings, rotary machines, and life medicine under various boundary restrictions.

The major conclusions of this study are:

• Based on the results of the analysis using the experiment design program (DOE), that the optimal conditions for the highest frequency (769.78 Hz) were: the ratio of pores equal to (0.29857) and the height of the hollow equal to (0.019988 m), the thickness of the upper and lower plates equal to ((0.025 m), while the exponent of the functional gradient equals (k = 0.000945).
• In the buckling analysis, it was found that the optimum load was (785.788 kN) occurring at a pore ratio equal to (0.299), a hollow height equal to (0.01978m), the thickness of the upper and lower plates equals to (0.025 m), while the functional gradient exponent equals k=3).
• Based on the analytical results, the natural frequency increased by 2.6% when changing the porosity ratio from 10 to 20% at k = 0.5, hollow height 10 mm, and lamina 0.65 mm.

The major recommendations of this study are:

• Using the other plate theories, such as first-order deformation theories and high order theory to make theoretical analysis more efficient
• Using the mechanical convection for free vibration and buckling experiments of a composite structure made of functionally graded materials containing the pores of PFGMs.
• Employing the 3D printing method to manufacture samples can be used to describe the behavior of samples manufactured from functionally graded materials subjected to moving and static loads.

Congratulations! To our student Mr. Imad Kazem Najm

Department of Mechanical Engineering

University of Technology

Final Defense of a PhD dissertation

Titled “Parametric Study for Artificial Roughness Effect on Flow Boiling of Binary Mixture in Microchannel”

By:  Qahtan Adnan Abass Al-Nakeeb

Examination committee members:

Chair:

Prof. Dr. Ihsan Y. Hussain

 Members:

          Prof. Dr. Ihsan Y. Hussain

Asst. Prof. Dr. Abdulsattar J. M. Hassan

Asst. Prof. Dr. Ali L. Ekaid

Asst. Prof. Dr. Falah Fakher Hatem

By Supervision:

Prof. Dr. Ekhlas M. Fayyadh  

Asst. Prof. Dr. Moayed R. Hasan

Mr. Qahtan Adnan Abass Al-Nakeeb discussed his dissertation on 20^th December 2021 at 9:00 am, which aimed to investigate the effect of heat flux, mass flux, and artificial nucleation sites (ANS) on the onset of nucleation, flow boiling instability, pressure drop, and heat transfer coefficient on both deionized water and binary mixture (water-ethanol) at sub-cooled conditions. Further, the effect degree of sub-cooled for deionized water and concentration for binary mixture were considered.

The major conclusions of this study are:

• The onset of boiling depends on the amount of mass flow, as increasing the mass flow of the fluid delays the boiling start of both the deionized water and the binary mixture,
• Increasing the inlet temperature of deionized water without saturation requires a higher heat flux to start boiling. In addition to reducing the amount of pressure drop through the microwave channel and reducing the heat transfer coefficient
• The stability of boiling depended on the amount of fluid inlet temperature without saturation in addition to the amount of mass flow and the amount of concentration of the mixture.

The major recommendations of this study are:

• The use of artificial vacuoles enhances the heat transfer performance highly via the microwave channel
• The use of the binary mixture can reduce the instabilities of boiling as it avoids the drying of the channel wall (keeps it moist).
• The increase in the number of vacuoles enhances pressure drop.

Congratulations! To our workmate Mr. Qahtan Adnan Abass Al-Nakeeb