نصر عبد الامير جبار الخالدي

Several parameters affect the properties of Portland cement and one of these parameters is the cooling rate of the clinker. If the effectiveness of the cooling method of the clinker increases, a good enhancement in the properties of Portland cement will be found. The counter pattern of air clinker flow was studied using (FLUENT 6.3.26). The dimensions of the cooling room in grate cooler, the constant mass flow rate of both clinker and air, different height ratios, and different clinker porosity were considered in this numerical work, which were studied with the effect of imposing a new direction of airflow for development and compared with a previous study where it was suggested that the direction of airflow is in an opposite direction to that of the clinker flow inside the grate cooler. The results show that the heat transfers in the first half of the cooling room (0 < X < 0.9 m) is larger than that in the second half (0.9 < X < 1.8 m), and this leads to an increase in the temperature of outlet air so can benefits from it in the heating of furnace. When the clinker and air are flowing in the counter direction, the cooling method is more beneficial when compared with that of parallel flow because the exiting clinker has a great rate of cooler and the air exits from the grate cooler is loaded with large thermal energy. Finally, it can design the best length of gate according to the required clinker temperature at the outlet side, and this results to reduce the cost of the cooling process accordin

The natural convection in a square cavity partially heated which is created by adiabatic and isothermal for the horizontal and vertical boundaries respectively. Two isolated baffles linked to vertical walls with different arrangements is studied numerically in this article. The length and location of the baffle are the important parameters affected by natural convection, therefore, these parameters have been investigated for different Rayleigh numbers. The total length of baffles is assumed to be constant (i.e. the sum length of baffles on hot and cold walls equals the length of the square cavity). The results of this study show that the position and length of baffles have a significant effect on the flow characteristics and heat transfer of the enclosure. When the Rayleigh number increases, the average Nusselt number increases too. Also, the directly proportional governs the relationship between Nu increasing and increases in the length of the obstacle in all cases. The positions

An experimental and theoretical study for heat transfer through thermoelectric cooling system in this paper was presented. An experimental work was conducted to evaluate the performance of a thermoelectric module fitted to a sun flower heat sink with a similar sized heat source. The experimental investigation was done to evaluate the effect of TE input voltage, flow rates of cooling air and heat source (heating element) power input on the performance of a thermoelectric cooling system. Four low heating load (1.7, 2.4, 3.6 and 5 W) were used and hot side was fitted to a sunflower heat sink with forced convection. Experimental results show that the increasing of cooling air flow rates improves system performance, while increasing in applied TE voltage leads to deterioration it. The COPmax obtained is about 4.7 at 2V TE voltages and 5W heating load, and then decreased sharply as voltage further increased and reaches 0.13 at 12V. The results of the current study show that all Thermo-electric Cooling system recorded temperatures increase with increasing in heating load at a constant TE voltage and air flow rate. In addition to that the Tc decreases and Th increases with the increment of input voltage and that can lead to increase of the air temperature passing over heat sink. TE performance is highly affected by air flow rate. The theoretical result validated experimentally and shows an acceptable agreement between them.

his study is a numerical study. It investigates the steady state flow of fluid by natural convection in three dimensions as well as the transfer of heat for a set of innovative shapes of fin array. This study utilized four different shapes of fin array as well as the absence of fins. The different forms are as follows: straight, vertical (sine wave along y-axis), horizontal (sine wave along z-axis) and sweep (sine wave along both y and z axis). We examined the following parameters of the fin: geometrical dimension and thermal properties. In the steady state thermal analysis, an analysis of the differences in temperature regarding the distance at which heat flow takes place through the fin is carried out using CFX Ansys 15. The result shows that the sine wave along z-axis increases the transfer of heat more than the fin array of other shapes. Nusselt number increased as a result of the increasing heat flux which is exerted on the base as a boundary condition.

The properties of Portland cement depend on several parameters, and the cooling method is one of these parameters. When the effectiveness of cooling method increases, the properties of Portland cement are enhanced. In the present work, a new cooling method is suggested and numerical analysis is made by CFD modeling using (FLUENT 6.3.26). Using the same dimensions of cooling room in grate cooler, constant mass flow rate of air and clinker, different porosity of clinker, and different height ratios ( height of air / height of clinker), the numerical results were calculated. The results show that the height ratio is an important factor affecting the new cooling method and can be used in order to decrease the length of cooling room or the time of cooling process according to the porosity of clinker. The maximum temperature of clinker with the lowest possible porosity is much lower than the maximum temperature of clinker with maximum porosity at a constant height ratio (H.R.). Also, when the height ratio (H.R.) increases, the temperature of clinker decreases at any point, also the rate of change between clinker and air temperature decreases with increasing the height ratio (H.R.).

Natural convection heat transfer through a fluid-saturated porous media in inclined cylindrical enclosure was investigated experimentally and numerically in the present work. Numerical solution of the governing equations was made with the appropriate boundary conditions by using a CFD code FLUENT (fluid flow) 6.3.26. The experiment tests were carried out for inclination angles (0o, 25o, 50o, 70o, and 90o) at period ranges (10,22,50, and 90 min ) and amplitude (500,1000, 1500, and 2000 w/m2). The Results indicate an increase in the heat transfer with increasing of Rayleigh number, time, amplitude, period and angle of inclination from the horizontal position. Theoretical predications agree well with experimental results

العنف ضد الطفل في المواثيق الدولية والشريعة الاسلاميةاسبابه وطرق علاجه

تستهدف الدراسة عن ذوي الاعاقة واهم المشاكل التي تواجههم وكيفية ادماجهم بالمجتمع

تستهدف الدراسة عن الاستهلاك السلبي للمياه في العراق وطرق تقليله