Journal of Engineering

Experimental investigation of the influence of inserting the metal foam to the solar chimney to induce natural ventilation are described and analyzed in this work. To carry out the experimental test, two identical solar chimneys (without insertion of metal foam and with insertion of metal foam) are designed and placed facing south with dimensions of length× width× air gap (2 m× 1 m× 0.2 m). Four incline angles are tested (20o,30o,45o,60o) for each chimney in Baghdad climate condition (33.3o latitude, 44.4o longitude) on October, November, December 2018. The solar chimney performance is investigated by experimentally recording absorber plate and air temperatures and velocity of air. Results indicated that the using metal foam absorber plate lead to reducing the mean temperature of absorber plate by 6.7 °C as a result, the values of chimney outlet air temperature increased. The daily solar chimney efficiency enhanced by 58.7% and the useful energy received also increased. The existence of metal foam caused higher air velocity at the exit and increasing in the ventilation rate that the maximum ventilate rate obtained from the solar chimney is 5.96 1/hr for 27 m3 volume of room at solar irradiance of 730 W/m2 for chimney incline angle of 60o. The results of the experimental work show that the addition of metal foam to the solar chimney as an absorber plate is an efficient method to enhance the characteristics of heat transfer and the thermal performance of the solar chimney in the weather condition of Iraq.

The performance analyses of 15 kWp (kW peak) Grid -Tied solar PV system (that considered first of its type) implemented at the Training and Energy Research Center Subsidiary of Iraqi Ministry of Electricity in Baghdad city has been achieved. The system consists of 72 modules arranged in 6 strings were each string contains 12 modules connected in series to increase the voltage output while these strings connected in parallel to increase the current output. According to the observed duration, the reference daily yields, array daily yields and final daily yields of this system were (5.9, 4.56, 4.4) kWh/kWp/day respectively. The energy yield was 1585 kWh/kWp/year while the annual total solar irradiation received by solar array system was 1986.4kWh/m2. The average power losses per day of array, system losses and overall losses were (1.38, 0.15, 1.53) kWh/kWp/day respectively. The average capacity factor and performance ratio per year were 18.4% and 75.5% respectively. These results highlighted the performance analyses of this PV solar system located in Baghdad city. The performance can be considered as good and significant comparing with other world PV solar stations.

A numerical and experimentally investigation for two types of winglets (spiroid and blended), which are used to reduce the induced drag caused by the trailing vortices were presented and discussed in this work. The SOLIDWORK 2016 was used to model a rectangular wing geometry
of NACA2415 cross-sectional airfoil with blended and spiroid airfoils (2415 and 0012). The steady, incompressible N.S equations with standard (????-ω) turbulence model were simulated and solved by ANSYS FLUENT 18.0 for turbulent flow. The three-dimensional printer was used to manufacture the models in the experimental work. The present work focused on the difference between two types of winglets of aircraft which are performed in a low-speed wind tunnel of 55m/s maximum speed and (0.7m × 0.7m × 1.5m) rectangular test section. The flow field and the aerodynamic characteristics of lift coefficient, drag coefficient, pitching and bending moment coefficient were investigated with lift to drag ratio for different angles of attack numerically and experimentally at Reynolds number of 3.72x105. The results show that in general, the maximum lift to drag ratio for two winglet configurations for 6̊ angle of attack is 20% different for blended winglets as compared with spiroid winglets. The results show that the blended winglet is more effective than spiroid winglet at low angles of attack, but for high angles the spiroid winglet is.

An experimental study on a KIA pride (SAIPA 131) car model with scale of 1:14 in the wind tunnel was made beside the real car tests. Some of the modifications to passive flow control which are (vortex generator, spoiler and slice diffuser) were added to the car to reduce the drag force which its undesirable characteristic that increase fuel consumption and exhaust toxic gases. Two types of calculations were used to determine the drag force acting on the car body. Firstly, is by the integrating the values of pressure recorded along the pressure taps (for the wind tunnel and the real car testing), secondly, is by using one component balance device (wind tunnel testing) to measure the force. The results show that, the average drag estimated on the baseline car for different Reynolds numbers was (0.381) and the drag force was reduced by adding a spoiler and a slice diffuser to (4.45%, 1.5%) respectively, whereas the amount of drag reduction was (5.46%) when all drag reduction modifications were added together on the base car. No effect was noticed as vortex generators when added separately. The deviation in the drag coefficient from the real car testing was about (6.2%) and shows a very good agreements between the real car test and that of the wind tunnel test.

As the prices of the fuel and power had fluctuated many times in the last decade and new policies appeared and signed by most of the world countries to eliminate global warming and environmental impact on the earth surface and humanity exciting, an urgent need appeared to develop the renewable energy harnessing technologies on the short-term and long-term and one of these promising technologies are the vertical axis wind turbines, and mostly the combined types. The purpose of the present work is to combine a cavity type Savonius with straight bladed Darrieus to eliminate the poor self-starting ability for Darrieus type and low performance for Savonius type and for this purpose, a three-bladed Darrieus type with symmetrical S1046 airfoil was tested experimentally and numerically at different wind speeds (4.5 m/s, 8 m/s and 10 m/s) and it showed a poor self-starting ability at low wind speed although its higher performance at high wind speed. However when adding the cavities in two setup configuration and testing it at the same conditions, it was found that when adding the cavities as reversed cups in the core of the turbine, the performance increased and the power coefficient reached a maximum value at 10 m/s wind speed and it was observed to be 0.0914 , but when the solidity increased by adding three cavities, the performance was higher at low wind speed (4.5 m/s) but it tragically decreased at higher wind speed which indicates that the performance depends on the solidity and the turbine configuration. On the other hand, the numerical simulation showed a good match with the experimental results although it under-predicted the performance

Experimental tests were carried to control lost circulation in the Khabaz oil field using different types of LCMs including Nano-materials. A closed-loop circulation system was built to simulate the process of lost circulation into formations. Two dolomite plugs were used from different depths of the formation of Azkand in Khabaz oil field. The experimentations were carried out to study the effect of different types of LCMs, cross-linked copolymer (FLOSORB CE 300 S), SiO2 NP, and Fe2O3 NP, on mud volume losses as a function of time.
The rheological measurements of the nanoparticles-reference mud system showed that both of the SiO2 NP and Fe2O3 NP worked best at 1.2 g/l. and the closed-loop circulation system showed that SiO2 NP cured losses by 48.3% and 37.5% for core plugs 5C1 and 1C2 respectively which is better than Fe2O3 NP loss curing which was 37.9% and 31.3% for core plugs 5C1 and 1C2 respectively.
On the other hand, FLOSORB CE 300 S- Fe2O3 NP-reference mud systems cured losses up to 69% with 0.25g/l FLOSORB CE 300 S and 79.3% with 0.5 g/l FLOSORB CE 300 S which is better than the FLOSORB CE 300 S- SiO2 NP-reference mud systems results.

Asmari is the main productive reservoir in Abu Ghirab oilfield in the south-east part of Iraq. It has history production extends from 1976 up to now with several close periods. Recently, the reservoir suffers some problems in production, which are abstracted as water production rising with oil production declining in most wells. The water problem type of the field and wells is identified by using Chan's diagnostic plots (water oil ratio (WOR) and derivative water oil ratio (WOR') against time). The analytical results show that water problem is caused by the channeling due to high permeability zones, high water saturation zones, and faults or fracturing. The numerical approach is also used to study the water movement inside the reservoir. A three dimensional geological and a three phase reservoir model was constructed for Asmari reservoir. The simulation model was used to visualize the water front advance in order to evaluate the water production structurally. The numerical results also show that the channeling is the main cause of water production, as well as, oil-water contact advance problem was noted due to fault sealing behavior effects.

The reduction in the rivers capacity is one the most important issue to give the decision maker an idea during the flood season. The study area included the rivers of the Al Atshan, Al Sabeel and Euphrates, which are surveyed with a length of 21, 5 and 20 km respectively. The Euphrates , the
Atshan and Al Sabeel rivers were simulated by using HEC-RAS 5.0.3 software to study the real condition within the city of Assamawa. As well as the simulation was implemented by modifying the cross sections of the Euphrates and Al Sabeel rivers to increase their capacity to 1300 and 1200 m3/s respectively which are a flood discharges100 year return periods. The results showed that the maximum discharge capacity under real conditions of Euphrates River is 750 m³/s and both Al Atshan and Al Sabeel arms are 500 m3/s.

In this paper two axis sun tracking method is used to absorb maximum power from the sun's rays on the solar panel via calculating the sun’s altitude and azimuth angles, which describe the solar position on the Iraqi capital Baghdad for the hours 6:00, 7:00, 8:00, 9:00, 12:00, 15:00 and 17:00 per day. The angles were calculated in an average approach within one month, so certain values were determined for each month. The daily energy achieved was calculated for the solar tracking method compared with the fixed tracking method. Designed, modeled and simulated a control circuit consisting of reference position truth table, PI Controller and two servomotors that tracked the sun position to adjust the PV panel perpendicular on the rays of the sun. The results obtained by a simulation software MATLAB/Simulink.

Strengthening of the existing structures is an important task that civil engineers continuously face.
Compression members, especially columns, being the most important members of any structure,
are the most important members to strengthen if the need ever arise. The method of strengthening
compression members by direct wrapping by Carbon Fiber Reinforced Polymer (CFRP) was
adopted in this research. Since the concrete material is a heterogeneous and complex in behavior,
thus, the behavior of the confined compression members subjected to uniaxial stress is investigated
by finite element (FE) models created using Abaqus CAE 2017 software.
The aim of this research is to study experimentally and numerically, the behavior of square plain
(without steel reinforcement) concrete compression members, that has concrete strength of fc
′ =
24.41 MPa, confined with one layer of CFRP wraps under uniaxial compressive loading. Finally,
the outcomes are compared with the finite element models using Abaqus software.
Laboratory experimental results showed that confining compression members with CFRP wraps
is an efficient strengthening method. In terms of load carrying capacity, an enhancement was
measured for about 56.1% of the reference non-confined members. This enhancement was also
reached using Abaqus software.

This research shows the experimental results of the bending moment in a flexible and rigid raft foundation rested on dense sandy soil with different embedded depth throughout 24 tests. A physical model of dimensions (200mm*200mm) and (320) mm in height was constructed with raft foundation of (10) mm thickness for flexible raft and (23) mm for rigid raft made of reinforced concrete. To imitate the seismic excitation shaking table skill was applied, the shaker was adjusted to three frequencies equal to (1Hz,2Hz, and 3Hz) and displacement magnitude of (13) mm, the foundation was located at four different embedment depths (0,0.25B = 50mm,0.5B = 100mm, and B = 200mm), where B is the raft width. Generally, the maximum bending moment decreased with increasing the embedment depth from zero to B, by (75%,41%, and 43%) for the flexible raft under (1, 2 and 3) Hz respectively, for the rigid raft the maximum bending moment decreased by (62%, and 37%) under (1and 2) Hz respectively, for 3Hz excitation frequency, the direction of behavior wasn't the same for the case of the rigid raft foundation as the maximum bending moment increased with increasing the embedment depth from zero to (0.25B,0.5B and B) by (142% , 268% and 5%) compared with the surface raft foundation.

For the time being, the cold-formed sections are widely used due to their simple manufacturing and construction processes. To be feasible, the strength of cold-formed columns should be determined based on their post-buckling behavior. Post-buckling relations are cumbersome and need design aids similar to those of American Iron and Steel Institute (AISI) to be applicable. These design aids have been developed to sections and materials other than those available in the local market. Therefore, this paper tries to develop a general finite element model to simulate the postbuckling behavior of cold-formed steel columns. Shell element has been used to discretize the web, flanges, and lips of the column. A linear bucking analysis with subspace Eigen value scheme has been achieved to determine the global, distortional, and local mode shapes. Subsequently, these modes have been used to generate the correspond imperfections. Finally, the modified Riks method has been used to solve the nonlinear equations of equilibrium and to a void the possible snap through phenomenon. Comparing with the traditional analyses using the effective width method and the direct strength method indicates that the finite element analysis is adequate and can be used for practical applications when dealing with local sections and materials.
Finally, different case studies with different column spans have been considered to show the behavior of the column for different slenderness ratios.

This is a survey study that presents recent researches concerning factional controllers. It presents several types of fractional order controllers, which are extensions to their integer order counterparts. The fractional order PID controller has a dominant importance, so thirty-one paper are presented for this controller. The remaining types of controllers are presented according to the number of papers that handle them; they are fractional order sliding mode controller (nine papers), fuzzy fractional order sliding mode controller (five papers), fractional order lag-lead compensator (three papers), fractional order state feedback controller (three papers), fractional order fuzzy logic controller (three papers). Finally, several conclusions were drawn from the results that were given in these papers.

Biodiesel production process was attracted more attention recently due to the surplus quantity of glycerol (G) as a byproduct from the process. Glycerol Utilization must take in to consideration to fix this issue also, to ensure biodiesel industry sustainability. Highly amount of Glycerol converted to more benefit material Glycerol carbonate (GC) was one of the most allurement compound derived from glycerol by transesterification of glycerol with dimethyl carbonate (DMC). Various parameters have highly impact on transesterification was investigated like catalyst loading (1-5) %wt., molar ratio of DMC: glycerol (5:1 – 1:1), reaction time (30 - 150) min and temperature (40 – 80) ᴼC. The Optimum glycerol carbonate yield (YGC) and glycerol conversion (XG) was obtained 94.2% and 94.5% respectively at catalyst loading 5% wt., temperature 70ᴼC, DMC:G ratio 5:1 and 120 min. GC has large scale of uses such as liquid membrane in gas separation, surfactants ,detergents , blowing agent , in plastics industry, in Pharmaceutical industry and electrolytes in lithium batteries.