Iraqi journal of mechanical and material engineering

Liquefied petroleum gas LPG is a good alternative to gasoline fuel. It has emerged as a solution to the deteriorating urban air quality problem especially in an oil country like Iraq. Computational model is used for parametric study of spark ignition engine works on Iraqi fuel (gasoline or LPG). Transient one dimensional continuity, momentum and energy equations are solved by two – step Lax wender off (Ritchmyer) approach to evaluate brake specific fuel consumption BSFC, brake power, brake thermal efficiency, volumetric efficiency, air fuel ratio, in cylinder pressure and exhaust gas temperature. Results revealed that LPG fuel improves BSFC by 3.11% as a maximum compare to gasoline for 10 kW brake power and 9.9:1 compression ratio. The maximum cylinder pressures predicted for LPG are lower than that for gasoline fuel. The volumetric efficiency was 76.8 % for engine works with, LPG at compression ratio 9.9:1. While that for gasoline was 85.9%. The equivalence ratio is higher for gasoline than that for LPG, since the first required higher air-fuel ratio for combustion. The reported maximum exhaust gas temperature for LPG is 706oC, while that for gasoline is 741.4oC.

In the present research the effect of corrosion on buckling behavior of 304 stainless steel with increasing of compressive dynamic loads was studied. There are long types of the columns were used. For compression test, there are 24 columns specimens were used in the dynamic axis, 12 columns tests were carried out with increasing in the dynamic axis of compressive load, while for the corrosion test was performed by using 12 specimens were buried for two months under the ground before tested them. The digital gauge was employed at the distance about 0.7 for the column length at the fixed end of column. has alarm system was used to define critical buckling and to avoid the failure of the specimen and installed at the distance equal to 0.7 of the column length from fixed end. The empirical results showed that the effect of negatively corrosion on mechanical properties of alloys with 2.53% reduction of ultimate tensile strength comparing with non-corroded specimens, in the other hand the corrosion will reduce the critical buckling load by 6% for two months. The experimental results comparing with the standard theories of the buckling behavior and with the finite element (ANSYS) results to verify the mathematical model.

The evaluation of flat shallow cavity solar collector inserted with porous substrate was investigated experimentally and numerically. The aim of this work is to improve the thermal performance of flat plate solar collectors using enhanced heat transfer technique. Porous media were made of multilayer of aluminum mesh to form a porous layer of thickness 25 mm inserted under the absorber plate with porosity of 0.9 and permeability of 84.87. The solar collector was installed in Baghdad south facing at a fixed tilt angle (45°). Three types of solar collector have been designed and constructed namely solar collector made of shallow enclosure (model I), solar collector made of shallow enclosure inserted partially with porous layer (model II) and solar collector with channels of corrugated channels inserted partially with porous layer (model III). The results of parametric study of model III in case of continuous operating showed that the maximum average water temperature difference of water between collector outlet and inlet exceeds (7.21°C) and the maximum outlet temperature exceeds (50°C) at solar noon for (November, and December 2013). The thermal efficiency for collector model III was ranged from 47.52% to 52.2%, while that for model I was ranged (33.5% to 42.3%) under the same environmental conditions.

Friction stir spot welding (FSSW) is provided a premium difference to resistance spot welding and rivet process for making the structures of aluminum sheet and it is a new development. ANSYS works is done which conducted on dissimilar material sheets of a1.1mm thick sheet of aluminum alloy (AA2024-T3) and a 0.8mm thick sheet of carbon steel (1006-AISI). A 3-D finite element model was built using ANSYS APDL to simulate the thermal and mechanical model during FSSW. The welding processes are performed using cylindrical pin with a 10mm diameter. Three tool rotational speeds are used during FSSW processes (900rpm, 1400rpm, 1800rpm). Results showed that the maximum temperature was 242.57ºC in nugget zone of dissimilar spot weld, at 15sec with a 0.4mm depth and 135.752°C at 10sec with a depth of 0.2mm.

In this study , the adsorption of an industrial blue dye was investigated by using date palm tree waste . The effect of the process parameters such as, contact time ; adsorbate concentration, ( pH) and (temperature ) are reported . \\"Nearly 2-3 hr of contact time are found to be sufficient for the adsorption to reach equilibrium\\" (A better fixation was obtained at acidic pH (2) and room temperature 25◦C.

Hydrogen is a clean fuel for internal combustion engines since it produces only water vapor and nitrogen oxides when it burns. In this research, hydrogen is used as a blending fuel with diesel to reduce pollutants emission and to improve performance. It is inducted in the inlet manifold, of a single cylinder, four stroke, direct injection, water cold diesel engine, type (Kirloskar). Hydrogen blending is done on energy replacement basis. A special electronic unit is designed and fabricated to control hydrogen blending ratio. The maximum achieved ratio is 30% of input energy and beyond that engine operation becomes unsatisfactory when the air temperature is 20 oC and injection timing of -35o CA which represent the first part of this work. Inlet air heating system is built and added in the experimental work. The heating system allows to increase the air temperature up to 100 oC. A heating of air to 60 oC with injection timing of -30o CA and 55% of hydrogen blending is executed in the second part of this study. Tests are done with 17.5 compression ratio and 1500 rpm. The brake specific fuel consumption is reduced by 29% and 46%, the engine thermal efficiency is increased with 16% and 21% for the 1st and 2nd part respectively. The pollutant emissions of carbon oxides, UHC, and smoke opacity are dramatically decreased by 19.5%, 13%, and 45% respectively for the 1st part and 41%, 38% and 65.6% for the 2nd part while NOx emission is increased by 10% and 25% for the 1st and 2nd part respectively.