Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 40, Issue 7 (Mechanical Engineering

Volume 40, Issue 7 (Mechanical Engineering, 7 Articles), July 2022

Research Paper

Thermal Behavior Simulation of An Externally Cooled Electric Motor

Noureddine MENECEUR; S. Boulahrouz; A. Boukhari; R. Meneceur

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 926-941
DOI: 10.30684/etj.2021.131114.1006

This paper presents the simulation results of the thermal behavior for an externally cooled asynchronous electric motor in both steady and transient states cases. For this purpose, a mathematical model based on the heat equation is first developed to determine internal thermal sources such as copper, mechanical and iron losses. Then, a computer program is developed to numerically simulate the proposed mathematical model. This program determines the radial distribution of steady and transient states temperatures, and predicts the effect of the ambient temperature on the transient and permanent temperature distributions. This makes it possible to calculate the specific speed of the motor as a function of its rotation speed, the airflow rate and the pressure dropping at the fan level. The obtained results show that the engine heating is mainly due to the elements that show thermal losses by Joule effect. The mitigation of these losses is strictly related with the specific speed, which makes it possible to select the right choice of the engine cooling system. Using the nodal numerical method to determine the distribution of the radial temperature in both steady and transient states cases under the effect of the ambient temperature. The obtained results are analyzed and discussed.

Numerical Investigation of a Window Solar Air Collector with Moveable Absorber Plates

Norhan I. Dawood; Jalal M. Jalil; Majida K. Ahmed

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 942-950
DOI: 10.30684/etj.v40i7.2270

Window solar air collector is an imperative instrument for heating residential buildings in cold regions. This paper presents a numerical investigation of the thermal performance of a window solar air collector with seven moveable absorber plates. With glass on the front and back sides of the collector. By the use of FORTRAN 90; The three-dimensional steady-state turbulent forced convection method was used to solve the Navier-Stokes equations. The seven plates opened and closed at different angles in unison manually by a specific mechanical mechanism. The effect of changing the plate angles has been tested, alongside the effect of airflow rates and the intensity of solar radiation. Numerical results illustrate that air temperature difference is higher at vertical plates position (angle 0) compared to that at angle 90. In contrast, flexibility between sunlight penetrating the room and hot air from the collector will be gained when the plates are set on angle 90. Results indicate that the thermal performance was improved by 67% when the plates were set at angle 0. Maximum thermal efficiency for angle 0 was 72% at a mass flow rate of 0.0298 kg/s. However, maximum thermal efficiency was 51% at mass flow rate 0.0298 for angle 90°.

Economic Operation of Low Voltage Smart Micro-grid with Integration of Renewable Energy

Kadhim M. Jabber; Mohammed K. AL-Saadi; Ameer Jaddoa

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 951-958
DOI: 10.30684/etj.2022.131063.1000

This paper develops a unit commitment multi-period energy management system to minimize a low voltage microgrid's total operation and emission cost. The optimization problem is formulated in the mixed-integer quadratic program. The environment cost and battery degradation cost are taken into consideration in the proposed optimization approach. The unit commitment strategy is employed to minimize the total cost. A set of constraints are considered in the proposed optimization approach. The proposed energy management system is applied to the low voltage distribution grid, including different distributed generators, such as diesel engines, fuel cells, and microturbines. The microgrid also contains storage batteries, renewable energy resources, wind turbines, and photovoltaic panels. The results reveal that the storage battery charging and discharging operations are controlled to reduce the operation and emission cost even considering the battery degradation cost.

Study of the Effect of Working Fluids on The Thermal Performance of A Horizontal Heat Pipe with Stainless Steel Wick

ALI K. soud; Qusay J. Abdul Ghafoor

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 959-969
DOI: 10.30684/etj.2022.131137.1014

The present work aims to study the effects of working fluids on the thermal performance of the heat pipe with a wick and in a horizontal position. The experiments were conducted using a copper heat pipe with a 20.8 mm inner diameter, and the length of the evaporator, condenser, and the adiabatic regions were 300 mm, 350 mm, and 300 mm, respectively. The working fluids selected were water, Methanol, ethanol, and different binary mixtures (50: 50) %, (30: 70) %, (70: 30) % mixing ratios. The filling ratio was 50% of the evaporator volume for all working fluids, and the heat input values were 20, 30, 40, and 50 W. The results show that the heat pipe charged with Methanol has a thermal resistance of (0.85166oC/W), the lowest thermal resistance value. The lowest thermal resistance of using mixtures is (0.785 oC/W) for (50 % methanol: 50% ethanol). Both are achieved at 50 W heat input. Also, at 50 W heat input, the highest value of heat transfer coefficient when using water as a working fluid is (510.386 W/m2. oC), and for using a mixture (70 % water: 30% methanol) is (556.78 W/m2. oC).

Study Effect of Exhaust Gas Recirculation upon Emissions and Performance by Using European Diesel and Iraqi diesel

Lina Jamal; Adel M. Saleh

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 970-978
DOI: 10.30684/etj.2021.131273.1021

This study investigated the effect of exhaust gas re-circulation (EGR) on performance and exhaust emissions in a single-cylinder, air-cooled, and direct-injection diesel engine. The Iraqi diesel fuel (D100) and European diesel fuel (ED100) were utilized at different speeds from (2100 to 3300 in intervals of 300) using the recycling of exhaust gas by a ratio (0%, 5%, 10%, 15%, and 20%. The study showed that European diesel fuel positively impacts engine performance and emissions. Compared to Iraqi diesel fuel, European decreased diesel fuel the brake-specific fuel consumption by (10.96%), increased brake thermal efficiency by (8.67%), decreased exhaust gas temperature by (9.99%), and (NOX, UHC, and decreased (CO) emissions by (7.94%, 10.07%, and 36.98%) respectively. When using the EGR ratio, the highest percentage that can be used is (20%). If this percentage exceeds this, it will cause a flame loss because the recycled gases are inert. Furthermore, the results indicate that brake-specific fuel consumption increases by (15.395%) and brake thermal efficiency decreases by (13.44%) with increased EGR ratio. In contrast, exhausting gas temperature and NOX emissions decreases by (4.01% and 14.57%) respectively. Finaly, the UHC and CO emissions increased with the increase of EGR ratio.

Review Paper

Potential and Development of Horizontal Axis Wind Turbine Systems and Technologies: A Review

Mohammed Habib; Abdullateef A. Jadallah; Ahmed A. Hussein

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 979-989
DOI: 10.30684/etj.2022.132452.1117

Wind energy has a potency of playing a vital role in the future of energy demand providing and environment freshening in many areas of the world. Utilizing wind turbine systems has become a competitive recourse among other renewable energy sources in terms of cost-effectiveness and the transition toward renewable energy usage. Researchers and developers are constantly dedicated to innovating to improve the technology of designing wind turbine systems. Wind energy depends mainly on the wind velocity and the area that swept them, increasing the wetted area. This is done by either upscaling the area of the wind rotor or constructing multi-wind turbines according to the type of designs that fit modern innovative systems. Though large wind turbine units do not fit with all sites, especially in cities, these turbines may be installed offshore and onshore. This paper aims to explore the relevant works technologies related to the wind energy potential, developments, design improvements, and multi-rotor horizontal axis wind turbine systems (HAWTs). This was achieved based on favorable characteristics such as economic viability and clean energy resources. Hence, these aspects reduce the environmental impacts and improve technological advantages and profitability. The results of this paper provide a recognizable system's facts and platforms that can be easily utilized. Wind Energy has the potency of hybridization with other renewable energy resources, which play an important role in urban planning, smart cities, and Buildings integration.

Research Paper

Experimental Study on The Effect of Aspect Ratio on Flexural Behavior of Aluminum Sandwich Composite

Ganesh Radhakrishnan; Al Haitham Al Hattali; Al Muntasser Al Yahyai; Al Muntasser Al Riyami; Al Muatasim Al Hadhrami

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 990-995
DOI: 10.30684/etj.2022.134317.1234

Sandwich composites are one such kind of light-weight composites developed for structural and vehicle body buildings etc. Due to their remarkable features such as high specific strength, high toughness and resistance to inter laminar shear strength. In this study, commercially available aluminium sandwich composite (ASC) laminate was considered for investigating its flexural behavior and buckling behavior as it was mostly used for various structural applications. Flexural analysis was done for different aspect ratios in order to analyze the influence of cross section of the specimen and support span on the flexural capability of the sandwich beam. The composite specimens prepared for flexural test consist of length 150 mm and widths 15, 12 and 10 mm. The flexural test was done for support span of 90, 110 and 130 mm respectively. The performance measures of flexural test are maximum bending load, deflection, flexural stiffness and inter-laminar shear stress. The flexural analysis revealed the fact that the aspect ratio appreciably affected the flexural capacity of the sandwich composite laminates. Maximum flexural capacity with bending load around 3.5 to 4 kN and flexural stiffness around 2.5 to 4.7 kN/mm respectively was observed for the sandwich specuimen for the aspect ratios L/t = 30 and b/t = 5. Being a anisotropic structure, the flexural behavior of this sandwich composite exposed as a combination of bending and shear failure. The soft core material and ductile skin face sheets resulted in a combined failure against flexural load in static condition.

Numerical and Theoretical Analysis of a Spur Gear Using Composite and Conventional Materials

Jwan K. Mohammed; Dlair o. Ramadan

Engineering and Technology Journal, 2022, Volume 40, Issue 7, Pages 996-1005
DOI: 10.30684/etj.2022.133641.1198

A spur gear is one of the most common forms of precision cylindrical gear. In the industry, reducing the weight of gears while keeping their useful properties has become an even more pressing challenge. As a result, the investigators have made many attempts to reduce the weight of the gears. Despite these efforts, the problem still requires more research. This study presented a spur gear's modeling and finite element analysis using different materials. A three-dimensional spur gear was designed, modeled, and simulated using ANSYS software. Five different materials, including two conventional materials (stainless steel and copper alloy) and three different composite materials, including 50% carbon fibers reinforced in epoxy resin, 1.5% filler containing acetal, i.e., Graphene Reinforced Acetal,  and glass-filled polyamide. Composites were fabricated by varying the graphene quantity in Acetal nanocomposites. The spur gear stress was calculated theoretically using the Hertzian equation, and FEM was analyzed using ANSYS 14.0 under limited loading conditions and rotational speed. Although the obtained results showed that both methods were comparable, there was a significant difference between the two methods when 50% carbon fibers reinforced in epoxy resin matrix were used, which is Hertzian analysis was 250.13 MPa. In contrast, this result was reduced up to 152.13 MPa in FEM. The study concluded that among the different presented materials, 50% carbon fibers reinforced in epoxy resin matrix were the optimal material for spur gear fabrication due to their high strength and low density. Hence, the spur gear material can be replaced by 50% carbon fibers reinforced in the epoxy resin matrix.