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Aims and Scope
Editorial Board

1. Investigation on heat transfer augmentation using continuous and broken ribs on a plate of heat exchanger

Ghassan Fadhil Smaisim

Mechanical Engineering Department, University of Kufa, Iraq.

Abstract: Experimental and theoretical studies of the force convection heat transfer throughout a rectangular channel have been obtained. Rectangular rib surfaces inserted to improve the heat transfer amount from the heated plate to the working fluid with inlet velocity that achieves Reynolds numbers between the 500 and 2000 to cover a large range of laminar flow. Different parameters of the rectangular ribs (number of continuous ribs, number of discrete of rib, row arrangement) have been explored. In experimental work, the channel length to hydraulic diameter (L/Dh) is 3, an aspect ratio W/H of 2, roughness pitch p/e of 10, roughness height e/Dh of 0.06, and the attack angle of 90o. Nusselt numbers and the friction factor parameters compared with the corresponding values of the smooth channel at similar condition. The local heat coefficients and local hydrodynamic parameters have been obtained using the commercial ANSYS CFX 14.0 package. Numerical analysis extended to calculate the Nusselt number at 6.66≤p/e≤15, 0.064≤e/H≤0.096, 0.048≤e/Dh≤0.072. Comparisons of the heat results, the pressure drop and the thermal performance via earlier results have been collected. It’s observed that Nusselt number increases with Reynolds number and with use the rib surface for all models. The maximum enhancement in Nusselt number ratio observed to be 2.17 times the value of smooth channel for model 7 and friction factor is observed to be 2.18 for model 3. The overall enhancement ratio was 1.68-1.736 at Reynolds number about 1500 and its value declare slightly as the friction factor increases at the range near the transition regime. The best type of models was number 7. Heat transfer enhanced by rising the roughness height at fixed relative roughness pitch or by reducing the roughness pitch at fixed roughness height. Roughness pitch p/e could be augmented up to 10, further that there is a reduce in the heat transfer enhancement. The results compared with previous works and give good agreements.

Volume 9, Issue 3, 2018, pp.211-232.

2. Improvement in cold flow properties of biodiesel and its effects on diesel engine performance and emissions

Arvind Mangad, Murari Mohon Roy, Wilson Wang

Department of Mechanical Engineering, Lakehead University, Thunder Bay, Ontario, Canada, P7B 5E1.

Abstract: An experimental analysis was conducted to test the feasibility of biodiesel in the regions experiencing adverse cold weather conditions. Biodiesel was produced from canola oil by transesterification and fractionation processes. Winter diesel was used as a reference fuel. Three different fuel series were used: diesel-biodiesel with three blends (B20, B50 and B100), diesel-fractionated biodiesel (FB20, FB50 and FB100), and diesel-fractionated biodiesel with 2 volume percent of Wintron Synergy series (FB20S2, FB50S2 and FB100S2). All the fuel blend series were tested on a two-cylinder light-duty diesel engine to investigate effects of fuel blends on performance and emissions, under low, medium and high loads, at engine speeds of 1000, 2100 and 3000 rpm. Normal biodiesel and fractionated biodiesel with 2 vol% synergy showed significant improvement in the cloud point. FB40S2 had the lowest cloud point compared to other fuel blends measuring -48.5˚C. The emissions of carbon monoxide (CO), unburned hydrocarbon (HC), oxides of nitrogen (NOx) and smoke opacity from different fuel blends were measured and compared to that of diesel fuel. It was found that fractionated biodiesel and synergy blends were effective in reducing CO, HC and smoke emissions; however, all biodiesel blends increased NOx emission. Investigation results indicated that fractionated biodiesel with 2 vol% synergy had better engine performance and lower emission compared with diesel fuel and normal biodiesel blends. Thus, fractionated biodiesel up to 80 vol% with 2 vol% synergy was suitable for use in diesel engines in extreme winter conditions in Canada without the need for any engine modification.

3. Experimental investigation of submerged flow over piano key weir

Saleh I. Khassaf¹, Mohamed Baqer N. Al-Baghdadi²

1 Civil Engineering Department, College of Engineering, University of Basrah, Iraq.

2 Civil Engineering Department, Faculty of Engineering, University of Kufa, Iraq.

Abstract: Extensive experimental investigation has been performed to analyse the behaviour of piano key weir under submerged flow conditions. More than 2500 runs were performed on 14 physical models in an experimental rectangular flume, 15 m long and 0.3 m by 0.45 m cross-section. Effect of submergence phenomenon on the discharge capacity was studied for different discharge values. It was found that the discharge reduction factor Cs is mainly influenced by the submergence factor S. This effect starts when S is greater than the modular submergence limit which proved to be around 0.4 to 0.6. Models with different geometrical parameters were compared to each other and final conclusions about their effect on discharge capacity were achieved. However, the influence of all the geometrical parameters was small (less than 12%).

4. Preparation and characterization of γ-Al₂O₃ nanoparticles via chemical precipitation route: Effect of precursor concentration

Alaa Jassim Awadh¹, Saad H. Ammar¹, Ban A. Altabbakh²

1 Department of Chemical engineering, AL-Nahrain University, Baghdad, Iraq.

2 Petroleum Research and Development Center, Ministry of Oil, Iraq.

Abstract: In the present work, nano-sized γ-alumina powders have been successfully synthesized by control precipitation path using aluminum chloride as forerunner and water and ammonium solution as precipitating agents and at 70 °C. The synthesized γ-alumina samples have been characterized by XRD, AFM, SEM, and N2-adsorption/desorption isotherm at -196 °C by the BET method. Different initial concentrations of aluminium chloride precursor in ethanol solvent were studied on the particle size and surface area of the prepared γ-alumina. Results indicates that the sample prepared by this method gave nano-sized particle with crystallite shape in the range 70-91 nm, surface area 260-291 m²/g and pore volume 0.467-0.36 cm³/g.

5. Numerical simulation of indoor airflow and particle deposition in the clean room (surgical operation room)

Haider M.H. AL-Shami, Ali A. Monem, Emad A. Khazal

Department of Mechanical Engineering, Engineering College, University of Basra, Basra-Iraq.

Abstract: This study presents three-dimensional analysis Lagrangian model (DPM) for particle movement in turbulent indoor airflows inside the clean room (surgical operation room) in al-Najaf hospital in Iraq, to obtain the best appropriate environmental conditions within the room, and to account for the process of particle deposition at solid boundaries. These particles were originated from the supply air. The computations were accomplished with the aid of the computational fluid dynamics (CFD) program, known as ANSYS 15 program using (drift-flux) model. This program was validated against the results of a similar model given by chen. et.al [1], which shows a reasonable matching. The numerical results collected from the surgical operation room were done at different inlet velocities, to state the effect of turbulent inlet airflow velocity on the particles concentration around the room contents (specially the operation table), and to track the paths of these particles.

6. Effect of the carbon nanotube (CNT) in the materials used for prosthetics and orthotics applications

Jumaa S. Chiad, Wajdi Sadik, Abbas Hameed Jeryo

Department of Mechanical Engineering, College of Engineering, Al-Nahrain University, Baghdad, Iraq.

Abstract: In this work, the optimal mechanical properties of the lamination materials that used in manufacturing prosthesis and orthoses parts are studied. The optimization is selected according to high yield, ultimate stresses, bending stress and fatigue properties. The method of selection the  optimal materials is a response surface methodology (RSM) which depend on two parameters, reinforcement material Perlon fiber and percentage of multi-wall carbon nanotube MWCNTs which is mixed with matrix lamination resin. Thirteen samples are suggested according to RSM method by controlling two variables which are the layers number for Perlon and MWCNTs percentage. This method leads to select the optimum materials which give a maximum yield, ultimate and bending stresses. According to ASTM D638 and D790, the three imported tests are performed which are tensile, three-point bending and fatigue tests for all laminations materials as selected by RSM method and manufactured by vacuum method. Also, fatigue test is performed for optimal lamination material and compared with laminations manufactured in the previous study, 10 layers Perlon lamination and 424 laminations (4Perlon, 2carbon fiber and 4Perlon). The results obtained by Design Expert program version 10.0.2 showed that the lamination (10 layers Perlon and 0.75%of MWCNTs) is the optimum lamination according to the maximum yield, ultimate and bending stresses, and, endurance stress.

7. Ultrasonic impact peening technique for improvement the constant amplitude corrosion-fatigue interaction

Hussain J. Mohammed Al-Alkawi¹, Amer H. Majeed², Saba Farhan Naser²

1 University of Technology, Electromechanical Engineering Department, Iraq.

2 University of Al-Mustansiriya, Collage of Engineering, Material Engineering Department, Iraq.

Abstract: The fatigue behavior of 6061-T6 aluminum alloy under constant amplitude loading was investigated in air for as-received and pre-corroded specimens in 3.5% NaCl corrosive solution for 77 days. Constant corrosion-fatigue tests have been done with and without ultrasonic peening treatment under rotating bending load at stress ratio (R= -1) and room temperature (RT= 25 °C). The experimental results presented that the tests of fatigue life on pre-corroded specimens with and without ultrasonic peening revealed a significant reduction in life related with the presence of corrosion defects before cyclic loading. In state of unpeened specimens the constant S-N fatigue strength curve was decreased by 4.5% due to immersed the specimens in corrosive 3.5% NaCl solution for 77 days, while in state of ultrasonically peened specimens the reduction of S-N curve decreased to 2.2% due to the beneficial effect of this treatment for increasing the corrosion-fatigue life. The improvement of fatigue life and corrosion-fatigue life of specimens when applying of ultrasonic peening treatment was 8.69% and 2.3% respectively.

8. Modifying of fatigue characterization for natural rubber materials by carbon Nano-particle tube (CNT) reinforcement

Ali Hammoudi Al-Wazir

Kerbala Institute, Mechanical Department, Iraq.

Abstract: The main purpose of this paper is modified the strength and fatigue characterizations of natural rubber materials by reinforcement with Nano particle materials. Where the Nano particle used is carbon Nano-particle tube with various volume fractions, as (0.2% to 1%). Therefore, the strength on rubber materials, with various Nanoparticle volume fractions, is evaluated by using experimental technique by testing the tensile sample with universal test machine. After this, evaluate the fatigue characterizations of rubber materials, with various Nano particle volume fractions, by two techniques, first, experimental technique with manufacturing the fatigue test sample and then using rubber fatigue machine to testing its samples to evaluating the fatigue strength and life, and second, numerical technique by using finite element method with using Ansys program technique. Where, the experimental results of fatigue characterization are comparison with numerical fatigue results to shows the agreement between experimental and numerical technique. Therefore, its comparison shows the good agreement of fatigue results with maximum error between the two techniques use is about (10.28%). Finally, the results for strength and fatigue are shown that the strength and fatigue characterization are modifying with reinforcement by Nano particle carbon materials. Then, the increasing of Nano particle is lead to increase the strength and fatigue characterizations of natural rubber materials.

9. Using elastography to predict breast cancer

Bashar A. Bedaiwi

Al-Mustansirya University, College of Engineering, Mechanical Engineering Department, Iraq.

Abstract: In this work a finite element investigation carried out to predict breast cancer. Human tissues have varied rapidly stiffness. Recent approach called noninvasive elastography using the change in displacement and strain in tissues when subjected to load are used to detect the breast cancer without using biopsy or radiation. Malignant, benign and healthy tissue can be classified according to its response when simple weights (1, 2, 3 and 4 kg). Different built up equations are used in Ansys 11 to model the hyperelastic tissue behavior and simulate the soft tissue. The results show that a simple Finite element model with linear elastic material properties can be suitable to simulate the real case and can be used more to predict and comparison reason with elastography to predict the type of tumor.