Print ISSN: 1681-6900

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Volume 39, Issue 9

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Volume 39, Issue 9, September 2021

Hot Spot Analysis of Photovoltaic Module under Partial Shading Conditions by Using IR-Imaging Technology

Ali. Numan; Hashim Hussein; Zahraa Dawood

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1338-1344
DOI: 10.30684/etj.v39i9.841

The probable appearance of localized overheating (hot spot) represents one of the main matters for the reliability and safety of c-Si cells. It entails both a risk for the photovoltaic module's lifetime and a decrease in its operational efficiency. Partial shading is the most common cause of a hot spot in a PV system. The main aim of this work is to analyze the hotspot phenomena by I-V curve as well as IR thermography and investigate the impact of partial shading on the hottest cell experimentally to find its effect on the output power. The results show that at normal operating conditions (G=865W/m2 and Ta=39.7°C) the output power is 89.05W; the temperature difference between the hottest and cooled cell was about 6°C. Moreover, the short circuit current and consequently, the maximum output power reduced if only one cell fully or partially shaded. However, when the hottest cell is shaded by 25%, 50%, 75%, and 100% of the shaded area, the power losses were 37.17 %, 50.05%, 48.61%, and 52.86% respectively. Wheals, the hottest cell temperature was 80.6, 99.1, 101.4, and 62.4°C for 25, 50, 75, and 100% of the shading area, the major temperature difference observed at 75% of the shading area.

The Influence of Ultrasonic Impact Peening on the Mechanical Properties of Similar Friction Stir Welded Joints of AA 7075-T73

Abdul Ameer Jebur; Samir Amin; Ibtihal Mahmood

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1345-1351
DOI: 10.30684/etj.v39i9.1725

The purpose of this study is to study the ultrasonic peening influence upon the mechanical properties of the welded joints of 3 mm AA 7075-T73. Friction stir welding (FSW) was carried out by using milling machine and cylindrical tool with tapered pin. The used welding parameters were 710 rpm , 35 mm min for rotational and travel speed , respectively .Tensile tests results showed that the welding efficiency was about 60% for welded samples , and this value increased by using one and two lines ultrasonic peening treatment to 74% , and 71% , respectively , this improvement is due to generating compressive stresses along the surface of welded joints. The microhardness of the welded samples showed that there were fluctuations across the welded centerline and minimum hardness occur in the heat affected zone (HAZ).

Optimum Parameter Selection for Milling Different Laminate Composites Made by Hand Layup with CNC Milling Machine

Ghadak Alkhafaji; Fathi Alshamma; Enas Khalid

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1352-1361
DOI: 10.30684/etj.v39i9.1737

Recently, composite materials were widely used in different applications due to their lightweight, and good thermal and mechanical properties. In this study, an attempt to manufacture laminate composites by hand layup was performed. Also, optimal parameters for the best surface roughness were investigated. Therefore, three parameters had been examined; spindle speed, feed rate, and depth of cut. The L9 Taguchi orthogonal array, signal to noise (S/N) ratio, and analysis of variance (ANOVA) were selected to determine the optimum parameters. To create composites, the compression method was employed. Four different types of composites were manufactured with 2.8 mm thickness, to determine the effect of the parameters on the surface roughness and for specified parameters using the CNC milling machine. The weight fraction ratio of fibers was 39%, the polymer was 34%, and 27% for Aluminum. The results showed that the optimum parameters for surface roughness in milling machine of composites for Polyester resin for aluminum–fiberglass composite are; spindle speed=5000 r.p.m, feed rate=1600 mm/min, depth of cut=1.6 mm and Ra=1.853 μm, and for epoxy resin; aluminum–carbon fiber composite is spindle speed=4000 r.p.m, feed rate=800 mm/min, depth of cut=1.2 mm and Ra=2.43 μm.

Effect of Wavy Fins on Thermal Performance of Double Pass Solar Air Heater

Jalal Jalil; Rasha Nothim; Mustafa Hameed

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1362-1368
DOI: 10.30684/etj.v39i9.1775

In this paper, experimental study on double pass solar air heater with wavy fins absorber has been investigated. The fins attached to the upper and lower surfaces of the absorber. Two wavy fins arrangement (3 and 7 fins) have been investigated with plan absorber by changing solar radiation intensity (500, 600, 700 and 800 W/m2), air mass flow rate form 0.008575 kg/s to 0.0214375 kg/s. The results of wavy finned absorbers are compared with plane and the improving in thermal efficiency reached 80% and 84% in 3 and 7 wavy fins absorbers respectively.

Experimental Investigation of Dimensional Accuracy in Non-traditional Sheet Metal Spinning Process for Producing Rectangular Spun Part

ِِAmmar Saleh; Aseel Abd; Aqeel Bedan

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1369-1375
DOI: 10.30684/etj.v39i9.1974

The non-conventional spinning process was adopted for producing polygons, but one of the process limitations is the error between design and the final product especially with no-mandrel. Dimensional accuracy was adopted for this purpose which gives an indicator of the ability of the formed part to matches the design and checking validated of the adopted methodology for producing rectangular cross-section spun parts, by comparing the coordinating points of real part with the points of the design model. The point of a real part was measured by using a sphere probe fixed on the three-axis milling machine and capturing the data of machine axis movements for the center location of the probe, also, the measurements oppositely took place, by offsetting the points of design along the normal vector for comparison with the real part points. Three parameters were invested for study the effects on the dimensional accuracy, these parameters are spindle speed (48, 68, and 135 RPM), feed ratio (0.16, 0.22, and 0.32 mm/rev), and the ball diameter of the forming tool (16, 22 and 25 mm). The results show that tool ball diameter mainly affecting dimensional accuracy with a higher value of average error reach (6.47mm) when 16mm diameter of tool ball was used, on the other hand, the minimum average error was 1.705mm at low spindle speed.

An Experimental Investigation of The Dynamic Effects in Upper Drum Boiler Under Steam Mass Flow Rate Variation

Russul Mohammed; Hashim Hussein; Ali Numan

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1376-1383
DOI: 10.30684/etj.v39i9.1998

The dynamic effects in the “upper“ drum of the boiler (mechanical’s effects) are very complex problems and critical due to the pressure disturbance in the upper drum of the boiler. This work deals with an experimental investigation of the dynamic behavior of the boiler drum level system is reported from plant data (Al-Quds power plant) in Baghdad / Iraq under a particular condition of operating, and the mathematical equations of the boiler model variables explained and defined. The dynamic effects are investigated with increasing steam mass flow rate (10% and 20%) at the outlet of the boiler. The results showed that the rapid rise in the rate of steam mass flow causes the dynamic effects to increase (shrink and swell) by 15%, rates of evaporation and thus causes an increase in the volume of water inside the upper drum boiler that causes overheating in the tubes.

Enhanced Mechanical and Fatigue Properties In AA5052 Via TiO_2 Nanoparticles Addition Sintering Temperature (ST)

Zahraa Kadhim; Hussain Alalkawi; Ahmed Reja

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1384-1391
DOI: 10.30684/etj.v39i9.2020

The goal of the present work is to study the effect of different sintering temperatures (900, 1000 and 1100 ) on fatigue and mechanical characteristics of the metal matrix AA5052 reinforced with 5% of TiO2 nanoparticles. The stir casting process is used for manufacturing of AA5052/TiO2 nanocomposite. The mechanical characteristics of nano composites have been obtained at ambient temperature. The results of mechanical properties showed that the best enhancement in hardness (HB), ultimate tensile strength (UTS) and yield strength (YS) is occurred in nanocomposite with 1000  sintering temperature (ST). However, the fatigue test results showed that the samples manufactured under 1000  (ST) have longer fatigue life compared to other materials with different sintering temperatures. The endurance fatigue strength is improved by 7.2% compared to metal matrix. The experimental results showed that the microstructure image of 1000  (ST) composite has uniformly distributed of TiO2 in AA5052 matrix.

Electricity Generation from Hydro, Wind, Solar and the Environment

Olumide Towoju; Oluwatoyin Oladele

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1392-1398
DOI: 10.30684/etj.v39i9.2145

Human actions such as electricity generation are contributory causes of climate change. In a quest to reduce the emission of greenhouse gases associated with electricity generation from fossil fuels, the world is turning to renewables. Renewable sources, however, also do have an impact on the environment. Likewise, renewable electricity generation is also dependent on the climate. Hydro, Wind, and Solar are the popular renewable energy sources for the generation of electricity. This work reviews the impact of these renewables in electricity generation on the environment. It also considers the effect of climate change on its use. The construction of renewable electricity generating plants leads to habitat disruptions and can also cause fatalities. Climate change weighs an enormous impact on the performance of renewable electricity generating plants. The recent blackout experienced in Texas as a result of the cold weather is a good example. The end of extreme weather conditions is not yet, and the need to start preparing to prevent a blackout re-occurrence. A possible solution for sustainable renewable electricity generation in extreme weather conditions lies in synthetic fuel availability.

A Practical Study of The Thermal Performance of a Vacuum Tube For Solar Collector Using a Double -Sided Electronic Curtain With Nano-Fluid

Nagham Majeed; Khalid Sultan; Hosham Anead

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1399-1408
DOI: 10.30684/etj.v39i9.2029

In this research, a practical study and appraisal of the thermal performance for the solar collector with vacuum tube has conducted Two types of nanomaterials (aluminum and aluminum oxide) have added to distilled water with nanoparticles diameters of 30 nm and 50 nm respectively. The nanomaterials were used in three several concentrations and three several flow rates which used as a working fluid in evacuated tube solar collector (ETSC) in order to increase the efficiency and beneficial thermal gain. An electronic double-sided reflective and absorbent electronic curtain were added to enhance the performance and control the temperature of the nanoscale. A clear improvement in efficiency was observed when using the reflective curtain that helped to speed up the Nano fluid heating and controlling the required temperature.