Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : saturated

Enhancing Photoelectric Conversion Efficiency of Photovoltaic Panel Using Cooled Water by Evaporation

A.J. Kadem; S. R. Fafraj; I A. Hasan

Engineering and Technology Journal, 2017, Volume 35, Issue 5, Pages 525-531

It has been found a linear progression between the panel temperature and its efficiency. A novel cellulose pad arrangement, which is saturated with water, at back surface of photovoltaic panel for cooling has achieved better results. The experimental results showed a reduction in maximum PV panel temperature at using the proposed water cooling system. The average temperature of the PV panel dropped 10.1°C and an increase in average solar panel efficiency about 20.8% during operating time. Then, a comparison between the PV panel results cooling by natural convection and using the proposed water cooling system will reveal the most efficient.

Evaluation of Reinforced Sub-Base Layer on Expansive Sub-Grade Soil

Mohammed Y. Fattah; Aqeel S. Aladili; Hussam F. Yousif

Engineering and Technology Journal, 2016, Volume 34, Issue 9, Pages 1789-1803

Reinforcedpavementlayershavebeengainingpopularityinthefield ofcivil engineeringdue totheir highlyversatileandflexible nature.Withthe adventofgeosynthetics in civil engineering, reinforced earth technique has taken a new turn in its era. The practice of reinforced earth technique became easy and simple with geosynthetics. The research requirements are providing the materials and manufacturing of the loading machine (loading test apparatus). Materials include soil (bentonite), granularsub base, sand, and geogrid. The testing program consists of preparing of 6 models that represent layers beneath flexible pavement layers (subgrade and sub base layers). The model dimensions are 800*800*800 mm, subgrade layer is 400 mm thick and sub base layer 300 mm thick. The model tests include using geogrid reinforcement at the interface of the subgrade and sub base layer and in the center of sub base layer.
It was concluded that a geo-grid reinforced soil is stronger and stiffer and gives more strength than the equivalent soil without geo-grid reinforcement. Geo-grids provide improved aggregate interlock in stabilizing road infrastructure through sub base restraint and base reinforcement applications, Geo-grid reinforcement provided between the sub base course and subgrade soil carries the shear stress induced by vehicular loads and thus it reduces the load transferred to the subgrade and the volume changes induced by swelling of the subgrade soil. The load carrying capacity of the pavement system is significantly increased for geogrid reinforced sub base stretch compared to unreinforced sub base layer on expansive soil subgrade. Comparison of the results of the model without geogrid reinforcement with other models reveals that there is an increase in the bearing capacity of model that includes geogrid reinforcement at the interface of subgrade by about 40%; and 20% for the model that consists of geogrid reinforcement in the center of sub base layer.

Effect of Exit Pressure of Steam Turbine Last Stage Cascade Blade on Two Phases of Saturated Vapor and Water Droplet

Assim H. Yousif; Amer M. Al-Dabbagh; Reyadh Ch. Mahawi

Engineering and Technology Journal, 2013, Volume 31, Issue 2, Pages 235-244

Experimental investigation was carried out in low pressure steam turbine cascade to determine the effect of exit pressure on two phases of saturated vapor and fine water droplet. Numerical investigation was also presented by assuming the flow is two dimensional, compressible, turbulent, viscous, with the aid of the classical nucleation model applied for the mass transfer in the transonic conditions to predict the two phases behavior in the cascade. Comparison between experimental and theoretical results for the cascade flow was found to be fairly acceptable. Experimentally it was found that the most important influence of rapid condensation on the pressure distribution is on the suction surface. Also when the outlet is termed supersonic the heat release causes a pressure rise in the zone of rapid condensation, therefore the term "condensation shock" for this feature is misleading. In the numerical approach when the flow is regard subsonic the rapid condensation zone occurs downstream the throat and not accompanied by a pressure rise, while in the experimental test for the same case there is no sign of this condensation.