Tikrit Journal of Engineering Sciences

The Feasibility of sediment flushing from Mosul reservoir located northern iraq was conducted. Many upto date world criteria and indices for checking the efficiency of sediment flushing from reservoir which have been got through analyzing large amount of data from many flushed reservoirs in the world which were depended tested and applied in the present case study (Mosul Reservoir). These criteria and indices depend mainly on the hydrological , hydraulic and topographical properties of the reservoirs in-addition to the operation plan of the reservoirs. They gave a good indication for checking the efficiency of the sediment flushing process in the reservoirs. It was concluded that approximately the main criteria for the successful flushing sediment was verified in Mosul reservoir such as Sediment Balance Ratio (SBR) and the Long Term Capacity Ratio (LTCR),the shape factor of reservoir (W/L) and the hydraulic condition such as the percentage of (Qf/Qin) and (Vf/Vin). This gave an indication that the processes of flushing sediment in Mosul reservoir is probably feasible and may be applied in the future to maintain the water storage in the reservoir.

The present study emphasized on the information of cavitations during the dual phase flow i.e. (water and vapor) in venture converge-diverge nozzle. The choice of nozzle with a transparent material (PMMA), was found suitable for the observation and measurements. The model of this problem of defining dual compressible viscous flow, and k-epsilon model. The comparisons of numerical calculation and experimental observation were found to be comparatively coincidable in cavitational zone and throat pressure, and fractional phase flow.

In the present study a thermodynamic model for prediction of gas-liquid equilibrium at high pressures and different temperatures prepared for the binary systems of carbon dioxide (1) with each of the one of the liquid physical solvents (2) (sulfolane, n-methyl-2-pyrrolidone and propylene carbonate) using Peng-Robenson equation of state (PR-EOS) with different mixing rules to show the effect of the type of mixing rule used. Comparison of the experimental phase equilibrium data in the literature with the results of the model showed very good representation for some mixing rules and good for the others.

The present work studies the effect of noise on the dynamic response of pH, conductivity and thermocouple sensors which used into several industrial processes. Thermocouple would be proven had more stability against noise than conductivity and pH meter. The effect of noise on process signals could be condensate as low as possible by using suitable model of filter especially when the sensors were implemented to a digital computer.

This work treats the problem of heat transfer for perforated fins under natural convection. The temperature distribution is examined for an array of rectangular fins (15 fins) with uniform cross-sectional area (100×270 mm) embedded with various vertical body perforations that extend through the fin thickness. The patterns of perforations include 18 circular perforations (holes). Experiments were carried out in an experimental facility that was specifically design and constructed for this purpose. The heat transfer rate and the coefficient of heat transfer increases with perforation diameter increased.

A new design of three phase overcurrent relay described in this paper. The performance of the new design shows the ability to obtain any shape of characteristic with high accuracy and distinguish between transient and steady state fault. This design used more precise and flexible model Sachdev linear model for get any characteristic, also fast measurement theory to measure load current for less than half cycle and good hardware system design controlled by Pentium version 4 processor.

A numerical study of non-Darcian natural convection heat transfer in a rectangular enclosure filled with porous medium saturated with viscous fluid was carried out. The effects of medium Rayleigh number, porosity, particle to fluid thermal conductivity ratio, Darcy number and enclosure aspect ratio on heat transfer were examined to demonstrate the ability of using this construction in thermal insulation of buildings walls. A modified Brinkman-Forchheimer-extended Darcy flow model was used and no-slip boundary conditions were imposed for velocity at the walls and the governing equations were expressed in dimensionless stream function, vorticity, and temperature formulation. The resulting algebraic equations obtained from finite difference discritization of vorticity and temperature equations are solved using (ADI) method which uses Three Diagonal Matrix Algorithm (TDMA) in each direction, while that of the stream function equation solved using successive iteration method. The study was done for the range of enclosure aspect ratio ( 2 H / L 30 ) which is in the tall layers region at medium Rayleigh number (5 2000 m Ra ), Darcy number (Da=10-3, 10-4, 10-5 ), porosity ( =0.35, 0.45, 0.55), particle to fluid thermal conductivity (kS/kf=5.77, 38.5, 1385.5).The results showed that the Nusselt number is direct proportional to medium Rayleigh number and porosity and reversely proportional to Darcy number, ratio of particle to fluid thermal conductivity and enclosure aspect ratio. The variables that affect the heat transfer in the above arrangement was correlated in a mathematical equation that account better for their affects on heat transfer which is represented by mean Nusselt number (Nu).

The strain path for sheet metal may be changed during forming , this may be affect the forming limit curve (FLC) . In this work the FLC before and after prestraining was determined for aluminum alloy (2024 T3) to study the effect of this type of prestraining and in different values on the FLC. This alloy was chosen because it is used widely , specially in aircraft structures .It was shown that the using of uniaxial tension prestrain affects the FLC . The major strain in right side is increased with the increasing in the prestrain , while in the left side the effect is small.

An experimental forced laminar study was presented in this research for an air flowing through a circular channel for different angles ( gif.latex?0^0&space;%E3%80%96,30%E3%80%97^0,%E3%80%9645%E3%80%97^0&space;%E3%80%96,60%E3%80%97^0), the channel was heated at constant heat flux , the channel also was packed with steel and glass spheres respectively . The tests were done for three values of Peclets number (2111.71,3945.42,4575.47) with changing the heat flux for each case and five times for each number. The results showed that the dimensionless temperature distribution will decrease with increasing the dimensionless channel length for all cases with changing Peclet number, heat flux and inclination angles, and its lowest value will be for glass spheres at highest flux, while at lower flux for gif.latex?0^0 , and the decreasing in dimensionless temperature was closed for both types of packed at other inclination angles. The study declared that the local Nusselt number decreases with increasing the dimensionless length of the channel for both packeds and for different applied heat flux, also through this study it was declared that the average Nusselt increases as Peclet number increases for both packed. Its value for the glass spheres is greater than the steel spheres with percentage (98.3%) at small Peclet, and percentage (97.2%) at large Peclet number for the horizontal tube, and (98.3%) at small Peclet number and (97.8%) at large Peclet number at θ=gif.latex?%E3%80%9660%E3%80%97^0 . Through this study its was found that average Nusselt number increases along the channel as the heat flux increases, because the bulk temperature will increase as the flow proceeds toward the end of the channel , so the heat transfer coefficient will increase. It was declared from this study that in the case of the steel packed the heat transfer will occur mainly by conduction, while in the case of glass packed the heat transfer will occur mainly by laminar forced convection, where the lowest Nusselt number (Nu=3.8) was found when the pipe is horizontal and lowest heat flux and lowest Peclet number.

In this research the effect of repeated loads on the initial modulus of elasticity for the fiber reinforced concrete was studied by casting six standard cylinders specimen (150*300mm) for every ratio of fiber, three volume ratios of steel fiber (0,0.4,0.8,1.2)%,were used after 28 days the specimen was tested choosing mix with water cement ratio that gives slump about (80-100) mm. The modulus of elasticity for fiber reinforced concrete cylinders at 28 days for the same ratio were tested by applying load on the three specimens until failure. The other specimens was studied under loads ratio (50%, 60%,75%) from the ultimate load under 25 repeated load then the stress-strain curve was found until load failure. The modulus of elasticity was calculated from the linear part of the stress-strain relationship.