Iraqi journal of mechanical and material engineering

Numerical simulation of free convection air flow through a porous media in an
inclined rectangular cavity is studied. Physical problem consists of a rectangular
inclined cavity filled with a porous media. The top and bottom surfaces are thermally
insulated while the left and right walls are maintained at isothermal hot and cold
temperatures respectively. The two-dimensional flow is characterized using Under
Relaxation finite difference scheme. It is found that the two-dimensional flow is
characterized by the vortices that are initiated by the existence of buoyancy effect. The
problem considered deals with a two-dimensional internal, laminar, isothermal flow
in an inclined rectangular porous cavity. In this work, the Darcy model is used and
the governing equations are solved using Under-Relaxation explicit technique for
flow characteristics of Prandtl number at 0.7, an aspect ratio equals to 1.5, Rayleigh
number ranging 50 and 100, and inclination angles o, 50o and 90o
respectively. The results explain that the flow field is dominated by one cell rotating in
a clockwise direction and filling the cavity. Also, the variation of the average Nusselt
number with inclination angles is also presented. The results showed a good
agreement with other published results.

The wind turbine performance test has high aspect on wind energy utilization.
Present work wind tunnel testing of Savanious rotor performance with four blades.
Results compared with well-known wind turbine Savnious of two blades. Savanious
rotor models are manufactured in Industrial Engineering Company. The subsonic
wind turbine had been calibrated before the test. The rotting speed and torque
generated one turbine shaft are reported. Powers, power coefficient, tip speed ratio
and Rynolds number are calculated. Results show that Savanious rotor with two
blades give good performances compared with four blades rotor.

There are many parameters affecting on the martensitic transformation of
nonferrous alloys such as point defects, pores and heat treatment. In this work, the
effect of aging after direct quenching treatment and step-quenched treatment on the
Martensitic transformation of porous CuZnAL alloy are studied. X-ray diffraction
analysis is based to identify phases presence in the microstructure of examined
specimens. Optical microscopy and scanning electron microscopy examinations have
also studied for prepared samples. It has been shown that aging and step-queched heat
treatment lead to precipitate some intermetallic compounds in the Martensite matrix
which make the lower percentage of shape memory effects for prepared alloy.

In this research the wear rate of one type of the thermosetting polymer
(polyester) reinforced by ceramic particles (silica) has been investigated. A Pin -on-
Disc wear testing machine of variable speed has been used. Flat against flat sliding
surfaces under variable working parameters conditions have been tested.
Statistical and mathematical analyses were used to the processing of the
experimental data. A mathematical model was done which shows the wear rate of
composite materials as a function of grain size and weight fraction.
The results of flat sliding surfaces show that the wear rate of the specimens
depends heavily on the working condition. It increases with the increase of the load
and sliding speed.
The results also show that the wear rate decreases with the increase of the
weight fraction and the decrease of the grain size of the reinforcing particles. The
optimum wear resistance of the reinforced polyester was at weight fraction of (20 %)
and grain size of (25 m).

In this study free vibration of uniform curved beam with varying curvature and
taper thickness between the root and tip of beam are investigated by using the finite
element method using Ansys(9.0). nine models from curved beam all models have
four cases have different in taper ratio for the same curvature are studied. The results
obtained from this study are compared with the results of other investigators in
existing literature for the fundamental natural frequency and its found from this
results the natural frequency increase with increasing the taper ratio and curvature for
the servel models from curved beams. Finally the effect of the taper ratio and
curvature on the natural frequency are shown in graphics

The usage of inertia air filter to clean air passing to air consuming device has
few attention in spite of its importance .This work focuses on the idea and advantages
beyond this filter .A finite element solution of Navier- stoke equation in turbulent
Zone is used to obtain pressure and velocity distribution through typical section in
inertia air filter, these values are used to obtained the trajectory of different particle
size using four order Runge-kutta integration method .The path trajectory will device
on how large particles size can enter certain zone. Inertia air filter will prevent the air
consuming devices from stopping due to blocked air filter .A special design is
proposed so that to minimize loss with good ability in filtering dusty air .The usage of
inertia air filter will help in elongate the life time of the usual air filter without
appreciable increasing in pressure loss.

The present article summarizes an experimental study on the mechanical
behavior of high density polyethylene (HDPE)/ wheat straw (WS) composites. The
mean goals of this investigation were using of wheat straw (WS) as a filler
(reinforcer), effectiveness of straw flour fiber with different size (10-30 mesh as fine)
and (30-50 mesh as coarse) on mechanical properties of composites and effect of
maleic anhydride (MA) as a coupling agent treatment is performed to improve
interfacial adhesion between the fibers and HDPE matrix. Generally, (16) treatment
were conducted as (8) treatment of HDPE with 10, 20, 30, 40% coarse wheat straw
with (0.5, 1.0, 1.5, 2.0) MA, 8 treatments of (HDPE) with 10, 20, 30, 40% fine wheat
straw (WS) with (0.5, 1.0, 1.5, 2.0) MA, (HDPE) (WS). This study focused upon
tensile strength, flexural, impact strength and hardness of reinforced polyethylene.
The results showed that increase wheat straw rate to 30% in both fine and coarse,
improved [tensile, strength hardness flexural and impact strength] values, Fine (WS)
particles sample showed better, then coarse (WS) when addition for HDPE as fiber to
produced composite material.The optimum formulation for the (HDPE and WS)
composites on the mechanical properting is (30wt.%WS as fine-HDPE-1.5wt.%MA).

Used cylindrical steel case usually plated with zinc, to reuse these cases, dirt, oil,
grease, rust and old layer of zinc coat must be removed and again replated.
In a mechanical complex, cleaning and surface preparation of used steel case was
carried by mechanical method. Sanding lathe machines with an emery sandpaper
were used to do this job, this method has many disadvantages, some of are the low
production rate, the need for large manpower, original metal damage, it is expensive
and dust occur during slandering cause environmental problems at the jobsite.
In this case study cheap, and high production rate chemical method was proposed
and executed to clean and prepare steel case surface for recoating as alternative to the
mechanical method, the production rate increased more than tenfold compared with
mechanical method. The concentration of the consistent of the chemical solutions
and operation conditions were determined as a result of several experiments. Eight
steps technological procedure was suggested.

This paper provides an overview of the mechanical properties of reinforced Al
12%Si alloy by uni-directional of the eutectic phases in specific direction. A special
solidification unit have been designed and manufactured to ensure the correct
orientation of growing eutectic phase. Two types of insulation materials have been
used to isolate the carbon steel mold of solidification unit, (dry sand and glass wool).
The second type insulator found to be favorable in augmenting the growth and uni
direction of eutectic phase with the conditions of cold-water flow through the unit.
The produced microstructure consists of little elongated α-phase with a noticeable
correct orientation of the growing discontinuous eutectic phase in the direction of heat
sink. Hardness, tension, compression and impact properties have improved in
comparison with the samples of free mold isolation case (i.e. free solidification).
These results reflect directly the effect of uni-directional growth of eutectic phase in
the reinforcement process of the investigated alloy as an in situ-composite material.

In this work, an experimental and analytical solution for tensile properties of
hyper composite material is presented. The composite material consist of composite
matrix, bounded from resin material and short fiber, and long reinforcement fiber.
The result for the tensile properties of composite material combined from
composite matrix and reinforcement fiber, E1, E2, G12, and 12. In addition, the
results showing the effect of volume fraction of short and long fiber, and the types of
short and long fiber reinforcement, presented by analytical solution. And, the yield
stress of hyper composite material is defined by experimental study with various of
volume fraction of resin, short fiber, and long fiber.

Erosion and erosion-corrosion have important role in oil fields especially in steel oil
pipelines. Therefore; in the present work erosion and erosion-corrosion tests are studied
individually to investigate the relation between erosion and erosion-corrosion processes and
to quantify the synergy (that is caused by erosion) in realistic flow environments.
The experimental work tests were done using special device which was designed and
manufactured according to (G 73) ASTM.
The experimental work tests were achieved using traditional weight loss technique to
measure weight loss rates in (gmd) unit. Also, the microstructure observations of the test
specimens were studied.
It was observed that whole tests were conducted on oil pipe (X 60) made of low carbon
steel in plate form, tests were made on corrosion using 3.5 wt % sodium chloride. (NaCl)
solution as sea water purged with CO2 gas as the corrosive medium in crude oil, but in
erosion-corrosion 1 wt. % silica sand was added as slurry to that medium, pure erosion using 1
wt % silica sand as the erodent in distilled water purged with N2 gas as anti-corrosive medium
to get erosion just during pure erosion, all tests above were done in pumped media and
pumped media had constant pressure of 1 bar, flow rate Q = 36 L/min, temperature ≈ 25 ºC
and pH = 4.4 for erosive-corrosive media but pH = 7.4 for erosive medium.
After traditional weight loss technique was achieved, it was found that erosion rate (E.R)
was smaller than that of erosion-corrosion rate(E-C. R).

Several tests were carried out, such as Green, final porosity, densities,
compression, wear with (PinonDisk) type, hardness. Corrosion tests, which include
the simple immersion method and corrosion /erosion. The study indicated the increase
in weight loss for corrosion/erosion test with phase transformation before and after heat
treatment. The results indicate that the added alloy elements to the alloy based increase
in corrosion resistance about (113.3 – 566.6%). Also, high resistance in
corrosion/erosion of two alloys are calculated. When the heat treatment is carried out,
the improvement ratio is (488.9%), and the hardness has (185HV) value. The
compression strength and ductility have improved with excellent value. The mechanical
wear resistance has low change after heat treatment. While the addition of (Si) and
all the above-mentioned metals to the base alloy, increase the resistance to wear and
give the lowest corrosion The change case in weight with time indicate a stable case
after exposed to corrosion media.
The addition of (Si) metal with (3wt%) gave higher value in resistance to sliding wear
and follow in (Fe) metal in the same behavior, where the improvement ratio, are
(165%) and (126%). Alloy (CuAlNiMnFeSi) also demonstrates a high hardness,
low corrosion rate in sea water, good resistance to wear and compressive strain. These
improvements were attributed to enhancement of properties of alloy based (Cu – 9.5
Al) used in Marine propellers industry.