Department of Mechanical Engineering

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https://hdl.handle.net/11073/8414

Work by the faculty and students of the Department of Mechanical Engineering

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Finger-operated pumping platform for microfluidic preparation of nanoparticles
(Springer, 2024) Azmeer, Ahmed; Kanan, Ibraheem; Husseini, Ghaleb; Abdelgawad, Mohammad
Microfluidic preparation of nanoparticles (NPs) offers many advantages over traditional bench-top preparation techniques, including better control over particle size and higher uniformity. Although many studies have reported the use of low-cost microfluidic chips for nanoparticle synthesis, the technology is still expensive due to the high cost of the pumps needed to generate the required flows inside microchannels. Here, we present a low-cost finger-operated constant-pressure pumping platform capable of generating pressures as high as 120 kPa using finger-operated pumping caps that can be attached to any pop bottle. The platform costs around $208 and enables the generation of flow rate ratios (FRR) of up to 47:1 for the continuous flow synthesis of NPs. The pump has a resolution of 500 Pa per stroke and exhibits stable pressures for up to a few hours. To show the functionality of the proposed pump, we used it to prepare pegylated liposomes and poly lacticco-glycolic acid (PLGA) nanoparticles with sizes ranging from 47 nm to 250 nm with an average polydispersity of 20% using commercially available micromixer chips and in-house made hydrodynamic flow focusing devices. We believe this platform will render microfluidic preparation of NPs accessible to any laboratory with minimal capabilities.
Production of Targeted Estrone Liposomes Using a Herringbone Micromixer
(IEEE, 2024) Agam, Mohamed Abdalla; Paul, Vinod; Abdelgawad, Mohammad; Husseini, Ghaleb
Liposomes are spherical vesicles formed from bilayer lipid membranes that are extensively used in targeted drug delivery as nanocarriers to deliver therapeutic reagents to specific tissues and organs in the body. Recently, we have reported using estrone as an endogenous ligand on doxorubicin-encapsulating liposomes to target estrogen receptor (ER)-positive breast cancer cells. Estrone liposomes were synthesized using the thin-film hydration method, which is a long, arduous, and multistep process. Here, we report using a herringbone micromixer to synthesize estrone liposomes in a simple and rapid manner. A solvent stream containing the lipids was mixed with a stream of phosphate buffer saline (PBS) inside a microchannel integrated with herringbone-shaped ridges that enhanced the mixing of the two streams. The small scale involved enabled rapid solvent exchange and initiated the self-assembly of the lipids to form the required liposomes. The effect of different parameters on liposome size, such as the ratio between the flow rate of the solvent and the buffer solutions (FRR), total flow rate, lipid concentrations, and solvent type, were investigated. Using this commercially available chip, we obtained liposomes with a radius of 66.1 ± 11.2 nm (mean ± standard deviation) and a polydispersity of 22% in less than 15 minutes compared to a total of ∼ 11 hours using conventional techniques. Calcein was encapsulated inside the prepared liposomes as a model drug and was released by applying ultrasound at different powers. The size of the prepared liposomes was stable over a period of one month. Overall, using microfluidics to synthesize estrone liposomes simplified the procedure considerably and improved the reproducibility of the resulting liposomes.
Investigation of an integrated hydrogen production system based on nuclear and renewable energy sources: a new approach for sustainable hydrogen production via copper–chlorine thermochemical cycles
(Wiley, 2011) Orhan, Mehmet Fatih; Dincer, Ibrahim; Rosen, Marc
Hydrogen production via thermochemical water decomposition is a potential process for direct utilization of nuclear thermal energy to increase efficiency and thereby facilitate energy savings. Thermochemical water splitting with a copper–chlorine (Cu–Cl) cycle could be linked with nuclear and renewable energy sources to decompose water into its constituents, oxygen and hydrogen, through intermediate Cu and Cl compounds. In this study, we analyze a coupling of nuclear and renewable energy sources for hydrogen production by the Cu–Cl thermochemical cycle. Nuclear and renewable energy sources are reviewed to determine the most appropriate option for the Cu–Cl cycle. An environmental impact assessment is conducted and compared with conventional methods using fossil fuels and other options. The CO2 emissions for hydrogen production are negligibly small from renewables, 38 kg/kg H2 from coal, 27 kg/kg H2 from oil, and 18 kg/kg H2 from natural gas. Cost assessment studies of hydrogen production are presented for this integrated system and suggest that the cost of hydrogen production will decrease to $2.8/kg.
Design and simulation of a UOIT copper–chlorine cycle for hydrogen production
(Wiley, 2012) Orhan, Mehmet Fatih; Dincer, Ibrahim; Rosen, Marc
A design and simulation study of the four-step copper–chlorine (Cu–Cl) cycle using Aspen Plus software (Aspen Technology Inc., Cambridge, MA)is reported. The simulation consists of four main sections: hydrolysis, oxy-decomposition, electrolysis, and drying. This paper explains and justifies how the actual reaction kinetics is factored into these four main sections. Also, it illustrates all the process units that are used in the simulation of four-step Cu–Cl cycle, providing their associated specifications and design parameters. It is found that hydrolysis reactors with smaller capacities and larger (≥10/1) steam to CuCl ratios were desirable to increase the reaction efficiency and prevent the formation of side products such as CuO and CuC. In contrast, larger capacity oxy-decomposition reactors with longer residence times are preferable to allow enough time for the copper oxychloride to decompose. Therefore, 10 (or more) small-scale hydrolysis reactors can feed one oxy-decomposition reactor with large capacity to keep continuity of the flow in the overall cycle. On the basis of the process flow sheet, a pinch analysis is developed for an integrated heat exchange network to enable effective heat recovery within the Cu–Cl cycle.
Process simulation and analysis of a five-step copper–chlorine thermochemical water decomposition cycle for sustainable hydrogen production
(Wiley, 2014) Orhan, Mehmet Fatih; Dincer, Ibrahim; Rosen, Marc
A process model of a five-step copper–chlorine (Cu–Cl) cycle is developed and simulated with the Aspen Plus simulation code. Energy and mass balances, stream flows and properties, heat exchanger duties, and shaft work are determined. The primary reactions of the five-step Cu–Cl cycle are assessed in terms of varying operating and design parameters. A sensitivity analysis is performed to examine the effect of parameter variations on other variables, in part to assist optimization efforts. For each cycle step, reaction heat variations with such parameters as process temperature are described quantitatively. The energy efficiency of the five-step Cu–Cl thermochemical cycle is found to be 44% on the basis of the lower heating value of hydrogen, and a parametric study of potential efficiency improvement measures is presented.
Numerical Analysis of Film Cooling Shield Formed by Confined Jet Discharging on a Flat Plate
(International Information and Engineering Technology Association, 2019) Al-Hemyari, Mohammed; Hamdan, Mohammad; Orhan, Mehmet Fatih
The effects of centrifugal force and thermal conductivity on the effectiveness of a film cooling shield are investigated in this study. A confined jet with 90 degree angle is used, to inject cooling fluid into hot steam, to form a film cooling shield that protect a flat plate. Film cooling is modelled in 2D using ANSYS Fluent commercial computation fluid dynamic tool. The RNG k-ε turbulence model with enhanced wall function (EWF) is selected to capture the low-Reynolds number effects near the wall. The selected turbulence model has showed better prediction of the adiabatic film cooling effectiveness accuracy (AFCE) compared to other turbulence models. The results show that centrifugal force alters the flow field and affects the film cooling shield attachment to the flat plate. A clear drop in the AFCE is observed when positive centrifugal force acts perpendicular on the confined jet, which causes overheating in the vicinity of the jet. The effect of wall thermal conductivity on film cooling effectiveness FCE is reported using different thermal conductivity ratios between wall and fluid; mainly, 1, 10, 100, 1,000 and 10,000. The results show that thermal conductivity ratios less than 1 have almost no effect on FCE while high thermal conductivity ratios deteriorate the FCE in the vicinity of the jet.
Exergy analysis of heat exchangers in the copper–chlorine thermochemical cycle to enhance thermal effectiveness and cycle efficiency
(Oxford University Press, 2011) Orhan, Mehmet Fatih; Dincer, Ibrahim; Rosen, Marc
Most existing nuclear power plants in North America are typically water-cooled and operate at 250–500°C. For this temperature level, the copper–chlorine (Cu–Cl) cycle is one of the most promising cycles that can be integrated with nuclear reactors for hydrogen production by decomposing water into its constituents. In this study, we analyze the heat exchangers in the Cu–Cl thermochemical cycle so as to enhance heat transfer effectiveness and thereby improve the cycle efficiency. The thermal management options for internal and external heat transfer are studied and heat recovery opportunities are investigated and compared. Each heat exchanger in the cycle is examined individually based on the chemical/physical behavior of the process, and the most appropriate options are recommended. A thermodynamic analysis and associated parametric studies are performed for various configurations to contrast their efficiencies and effectivenesses.
Optimization of a Confined Jet Geometry to Improve Film Cooling Performance Using Response Surface Methodology (RSM)
(MDPI, 2020) Al-Hemyari, Mohammed; Hamdan, Mohammad; Orhan, Mehmet Fatih
This study investigates the interrelated parameters affecting heat transfer from a hot gas flowing on a flat plate while cool air is injected adjacent to the flat plate. The cool air forms an air blanket that shield the flat plate from the hot gas flow. The cool air is blown from a confined jet and is simulated using a two-dimensional numerical model under three variable parameters; namely, blowing ratio, jet angle and density ratio. The interrelations between these parameters are evaluated to properly understand their effects on heat transfer. The analyses are conducted using ANSYS-Fluent, and the performance of the air blanket is reported using local and average adiabatic film cooling effectiveness (AFCE). The interrelation between these parameters and the AFCE is established through a statistical method known as response surface methodology (RSM). The RSM model shows that the AFCE has a second order relation with the blowing ratio and a first order relation with both jet angle and density ratio. Also, it is found that the highest average AFCE is reached at an injection angle of 30 degree, a density ratio of 1.2 and a blowing ratio of 1.8.
Evaluating velocity and temperature fields for Ranque Hilsch vortex tube using numerical simulation
(Elsevier, 2021) Al Saghir, Ahmad Mohammad; Hamdan, Mohammad; Orhan, Mehmet Fatih
In this study, a three-dimensional numerical investigation is carried out to study the flow field inside a Ranque-Hilsch vortex tube (RHVT) model. Flow parameters such as velocity, temperature, and pressure are plotted at various locations inside the tube. The study reports the effect of cold mass fraction on the energy separation of vortex tube . The results show that the flow inside RHVT consists of a free vortex from r/R=0 to 0.9 and a force vortex from r/R=0.9 to 1 and that heat transfer occurs from the inner core to the periphery of the tube. Furthermore, it is observed that the minimum cold temperature and the maximum hot temperature are achieved at different mass fractions, 0.19 and 0.8, respectively.
Design and Comparison Analysis of Various Flow Configurations in Bipolar Plates via Numerical Simulation
(Canadian Center of Science and Education, 2021) Azzam, Mohammed H. A.; Qaq, Zabayyan; Orhan, Mehmet Fatih
Bipolar plates play a major role in the overall performance of fuel cells, hence their proper design and optimization are essential. In this regard, pressure drop across bipolar plates has a major impact on the efficiency. Therefore, it is crucial to minimize the friction between the plate walls and the working fluid, with a proper flow configuration, to eliminate pressure drops. The study, involved the simulation of various modified pin-flow bipolar plate configurations where a comparative analysis was carried out. A parametric study was performed to optimize various designs and operating parameters such as fluid flow, velocity and pressure. Computational fluid dynamics (CFD) was employed for the numerical simulation to ensure the optimum uniformity of fluid distribution. Results showed that the pressure drop is proportional to the velocity magnitude in the laminar region. Moreover, the pressure drop was minimized by eliminating the sharp edges in the flow channels.
Design and Optimization of Fuel Cells: A Case Study on Polymer Electrolyte Membrane Fuel Cell Power Systems for Portable Applications
(Wiley, 2022) Orhan, Mehmet Fatih; Saka, Kenan; Yousuf, Mohammad Hani
Fuel cells are energy conversion devices that directly convert chemical energy of fuels such as hydrogen to useful work with negligible environmental impact and high efficiency. This study deals with thermodynamic analysis and modeling of polymer electrolyte membrane fuel cell (PEMFC) power systems for portable applications. In this regard, a case study of powering a computer with a PEMFC is presented. Also, an inclusive evaluation of various parameters such as voltage polarization, overall system efficiency, power output, and heat generation is reported. In addition, a parametric study is conducted to study the effect of many design and operation parameters on the overall efficiency. Results show the direct influence of current density and temperature values on optimization of the design parameters in PEMFCs.
Fluid properties impact on energy separation in Ranque–Hilsch vortex tube
(Springer Nature, 2022) Al Saghir, Ahmad Mohammad; Hamdan, Mohammad; Orhan, Mehmet Fatih
This paper examines the energy separation in vortex tubes which is a passive device that can split a pressurized room temperature gas stream to hot and cold streams. The paper employs numerical simulations to investigate the impact of various working fluids such as helium, air, oxygen, nitrogen, and carbon dioxide on the energy separation in the vortex tube, using the SST k−𝜔 turbulence model with viscous heating. A three-dimensional numerical investigation is sued to examine the effect of a single fluid property on vortex tube performance, while keeping the rest of the fluid properties unchanged, which is impossible to achieve via experimental study. The numerical investigation examines the influence of molecular weight, heat capacity, thermal conductivity, and dynamic viscosity on energy separation. The results show that energy separation performance improves with lower molecular weight and heat capacity, and higher dynamic viscosity of the working fluids, while no impact of the thermal conductivity is observed. Out of five gases tested in this study, helium has yielded the maximum temperature separation, while carbon dioxide has yielded the lowest performance. Results show that viscous dissipation contributes to the temperature separation in vortex tube.
A Study and Assessment of the Status of Energy Efficiency and Conservation at School Buildings
(MDPI, 2022) Ragab, Karim Mohamed; Orhan, Mehmet Fatih; Saka, Kenan; Zurigat, Yousef
The building sector consumes a significant portion of global energy use. In this regard, this work was undertaken to study the status of energy efficiency and conservation at a large school building in the northern part of United Arab Emirates (UAE). The annual electrical consumption at the school was analyzed and an awareness survey among the students and teachers was conducted to measure the level of awareness as well as to assess the current energy consumption practices. In order to identify energy saving opportunities, an energy audit was carried out wherein the school energy consuming systems, particularly the lighting and air-conditioning systems, were assessed. Furthermore, thermography scanning of the school building envelope was conducted to examine the building insulation and identify air leakage locations. The building electricity supply and distribution systems were assessed using power analyzer and thermography devices. The energy conservation measures identified include removing the extra lighting, installing motion sensors in classrooms and labs, as well as integrating a Networked Optimization Software with the current HVAC (heating, ventilating and air conditioning) system. The methodology consists of seven fundamental steps: (1) case study data collection (analysis of buildings and utility data); (2) survey of real operation conditions; (3) understanding of building behavior; (4) analysis of energy conservation measures; (5) estimation of energy-saving potential; (6) economic assessment; and (7) proposing Energy Conservation Measures (ECMs). In this regard, the school energy consuming systems (lighting, building envelope, and air conditioning (AC)) were examined to identify possible ways to reduce the school energy consumption. The results indicate that the cost of installing motion sensors in classrooms, and labs is approximately AED 20,000 (United Arab Emirates Dirham), which yields an annual energy saving of AED 93,691. Furthermore, with all energy saving measures, a total annual saving of AED 364,000 is anticipated, which is approximately 16% of the annual electricity bill.
Variation in cooling performance of a bio-based phase change material by adding graphene nanoplatelets with surfactants
(Elsevier, 2022) Sheikh Mohammed, Yahya; Orhan, Mehmet Fatih; Umair, Muhammed; Mehaisi, Elmehaisi; Azmeer, Ahmed
In this paper, thermal characteristics of various phase change materials induced with additives and surfactants are studied to enhance cooling properties and chemical stability. In this regard, graphene nanoplatelets at various mass fractions are integrated with surfactant-induced-PureTemp PCM and used as a heat sink for an electric heating source. The surfactants considered in this study are sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and sodium stearoyl lactylate. The thermal characteristics are measured in terms of indices such as thermal conductivity, thermal capacity, and time of reaching the reference temperature. The results indicate that composite samples are superior in cooling when compared to the plain PureTemp PCM. Also, the highest thermal conductivity and phase change enthalpy are recorded in NanoPCM-SDS at 5% GnPs mass fraction and NanoPCM-SSL at 1% GnPs mass fraction amounting to 1.03 W/m.K and 236.5 J/g, respectively. NanoPCM-SSL displayed the longest delay of 1015 s to reach the reference temperature of 43 °C.
Melting performance of a composite bio-based phase change material: An experimental evaluation of copper foam pore size
(Elsevier, 2022) Sheikh Mohammed, Yahya; Orhan, Mehmet Fatih; Azmeer, Ahmed
This paper presents an experimental study on the thermal performance of a composite heat sink consisting of a bio-based phase change material and copper foam. The experiments are carried out at three different heat loads (10, 15, and 20 W) using five copper metal foam samples with the same dimensions (10 × 9 × 0.3 cm), porosity (98%), and pore densities of 20, 35, 60, 80, and 95 pores per inch (PPI). The thermal performances are evaluated using the temperature profiles, the time required to reach specific temperatures, and the enhancement ratios of the heat sinks. The results favor the PCM-Copper composite sample with 95 PPI because it took the longest time to achieve a constant temperature when compared to its other pore density counterparts. Also, for the same sample under 20 W power input, the enhancement ratios are 1.29, 1.45, and 1.23 at critical temperatures of 50, 55, and 60 °C, respectively.
Enhancement of the corrosion resistance of mild steel with femtosecond laser- nanostructuring and CrCoNi medium entropy alloy coating
(Elsevier, 2022) Ahmad, Shahbaz; Ahmad, Waqas; Abu Baker, Aya; Egilmez, Mehmet; Abuzaid, Wael; Orhan, Mehmet Fatih; Ibrahim, Taleb; Khamis, Mustafa; Alnaser, Ali
In this work, the corrosion resistance of mild steel surface nanostructured with a femtosecond laser and coated with high corrosion resistant CrCoNi (CCN) medium entropy alloy through magnetron sputtering is studied. Substantial improvement in corrosion protection was achieved by applying a combination of high-power femtosecond laser surface nano-structuring at ambient conditions and thin-film coating with (CCN) medium entropy alloy. XRD analysis revealed that femtosecond laser structuring increases the susceptibility of the surfaces to Fe₂O₃ nucleation through oxidation. The surface wettability measurements and electrochemical polarization tests revealed that the combined approach of femtosecond laser structuring and magnetron sputter coating is the best for desired high corrosion resistance. Through this novel method, the resulting corrosion resistance of mild steel was improved by more than one-fold. The results are explained considering the detailed microstructural analysis. The presented findings open new possibilities for corrosion prevention using a combination of new powerful technologies that yield to unprecedented corrosion-inhibition efficacy.
Energy assessment of an integrated hydrogen production systemEnergy assessment of an integrated hydrogen production system
(Elsevier, 2022) Shahin, Mohamed Shahin; Orhan, Mehmet Fatih; Saka, Kenan; Hamada, Ahmed T.; Uygul, Faruk
Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crisis, especially when produced from a renewable energy source. Solar energy is a renewable source that has been commonly utilized in the production process of hydrogen for years because it is inexhaustible, clean, and free. Generally, hydrogen is produced by means of a water splitting process, mainly electrolysis, which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system into a conventional Rankine cycle, producing electrical and thermal power used in domestic applications, and hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The model is divided into three subsystems: the solar collector(s), the steam cycle, and an electrolysis subsystem, where the performance of each subsystem and their effect on the overall efficiency is evaluated thermodynamically using first and second laws. A parametric study investigating the hydrogen production rate upon varying system operating conditions (e.g. solar flux and area of solar collector) is conducted on both parabolic troughs and heliostat fields as potential solar energy harvesters. Results have shown that, heliostat-based systems were able to attain optimum performance with an overall thermal efficiency of 27% and a hydrogen production rate of 0.411 kg/s, whereas, parabolic trough-based systems attained an overall thermal efficiency of 25.35% and produced 0.332 kg/s of hydrogen.
Design and Utilization of a Direct Methanol Fuel Cell
(MDPI, 2022) Ahmed, Aser Alaa Fathi Elsayed; Al-Lababidi, Malik Mamoun; Hamada, Ahmed T.; Orhan, Mehmet Fatih
This study introduces a step-by-step, summarized overview of direct methanol fuel cell (DMFC) fundamentals, thermodynamic–electrochemical principles, and system evaluation factors. In addition, a parametric investigation of a JENNY 600S DMFC is conducted to simulate cell performance behavior under varying operating conditions. The system is mathematically modeled and solved in MATLAB and accounts for multi-irreversibilities such as the activation and ohmic and concentration overpotentials. The performance of the modeled system was validated against theoretical and experimental results from the literature. The results indicated that increasing the fuel cell’s operating temperature yields enhanced output cell voltages due to enhanced methanol oxidation reactions. Nevertheless, the maximum efficiency limits of the fuel cell tend to decrease with an increase in temperature. In addition, the model has also depicted that enhanced output cell voltages are associated with increased oxygen consumption, resulting in the lower exit flowrates of the reactants.
Design and Analysis of Gas Diffusion Layers in a Proton Exchange Membrane Fuel Cell
(MDPI, 2022) Saka, Kenan; Orhan, Mehmet Fatih; Hamada, Ahmed T.
A proton exchange membrane fuel cell is an energy convertor that produces environmentally friendly electrical energy by oxidation of hydrogen, with water and heat being byproducts. This study investigates the gas diffusion layer (GDL) of the membrane electrode assembly (MEA) in proton exchange membrane fuel cells (PEMFCs). In this regard, the key design concerns and restraints of the GDL have been assessed, accompanied by an inclusive evaluation of the presently existing models. In addition, the common materials used for the GDL have been explored, evaluating their properties. Moreover, a case study of step-by-step modeling for an optimal GDL has been presented. An experimental test has been carried out on a single cell under various compressions. Lastly, a parametric study has been performed considering many design parameters, such as porosity, permeability, geometrical sizes, and compression of the GDL to improve the overall efficiency of the fuel cell. The results are presented in this paper in order to help ongoing efforts to improve the efficiency of PEMFCs and facilitate their development further.
Cooling potential for hot climates by utilizing thermal management of compressed air energy storage systems
(Springer Nature, 2022) Alami, Abdul H.; Orhan, Mehmet Fatih; Al Rashid, Rashid; Yasin, Ahmad; Radwan, Ali; Ayoub, Mohamad; Abdelkareem, Mohammad Ali; Alashkar, Adnan
This work presents findings on utilizing the expansion stage of compressed air energy storage systems for air conditioning purposes. The proposed setup is an ancillary installation to an existing compressed air energy storage setup and is used to produce chilled water at temperatures as low as 5 °C. An experimental setup for the ancillary system has been built with appropriate telemetric devices to measure the temporal temperature variation, which consequently can be used to calculate the heat transfer and available cooling capacity. The system is compared to commercially available compression cooling air conditioners, and the potential of replacing them is promising, as one ton of conventional cooling can be replaced with a 500-L (0.5 mᵌ) air tank at 20 bar operating for an hour. More tanks can be added to extend the operational viability of the system, which is also serving the original purpose of storing energy from grid excess or from solar photovoltaic panels. The thermal management has had the added benefit of increasing the roundtrip efficiency of the storage system from 31.4 to 35.2%, along with handling a portion of the cooling load.

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