Print ISSN: 1813-162X

Online ISSN: 2312-7589

Volume 15, Issue 2

Volume 15, Issue 2, Spring 2008, Page 1-111


EFFECT OF NOISE DISTURBANCES ON THE RESPONSEOF MEASURING DEVICES

K. T. Rashed; Dr. G. M. Alwan

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 50-61

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

FEASIBILITY STUDY OF SEDIMENT FLUSHING FROM MOSUL RESERVOIR, IRAQ

Thair Mahmood Al-Taiee

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 1-16

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.KEYWORDS: Flushing Sediment, Sluicing, Reservoirs

AN EXPERIMENTAL STUDY FOR HEAT TRANSFER ENHANCEMENT BY LAMINAR FORCED CONVECTION FROM HORIZONTAL AND INCLINED TUBE HEATED WITH CONSTANT HEAT FLUX, USING TWO TYPES OF POROUS MEDIA

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 15-36

دُرس في هذا البحث تجريبياً الحمل ألقسري الطباقي لهواء يجري في قناة دائرية المقطع موضوعة بزوايا مختلفة ومسخنة بثبوت الفيض الحراري، كما حشيت القناة بنوعين من المادة المسامية هما الكريات الفولاذية (Steel Spheres) والكريات الزجاجية (Glass Spheres) على التوالي، أجريت الاختبارات لثلاث قيم لعدد بكليت (2111.71، 3945.52، 4575.47) مع تغيير كمية الفيض الحراري المسلط لكل حالة ولخمس مرات لكل عدد. بينت النتائج المستحصلة إن توزيع درجة الحرارة اللابعدي ( ) يقل بازدياد طول القناة اللابعدي ولجميع الحالات من تغير عدد بكليت وتغير الفيض وتغير زوايا الميلان وتكون قيمته اقل بالنسبة للكريات الزجاجية عنه للكريات الفولاذية عند الفيض الكبير ويكون بالعكس عند الفيض القليل بالنسبة لزاوية الميلان ويكون النقصان في درجة الحرارة اللابعدية متقارب للحشوتين عند زوايا الميلان الأخرى. أوضحت الدراسة إن عدد نسلت (Nusselt number) الموقعي يقل بزيادة طول القناة اللابعدي في كلتا الحشوتين ولمختلف الفيض الحراري المسلط، وتبين من الدراسة ايضاً أن معدل عدد نسلت يزداد بازدياد عدد بكليت (Peclet number) في كلتا الحشوتين تكون قيمته اكبر في كريات الزجاج منه في كريات الفولاذ وبنسبة (98.3%) عند عدد بكليت القليل وبنسبة (97.2%) عند بكليت الكبير وعندما يكون الأنبوب أفقي وبنسبة (98.3%) عند عدد بكليت القليل وبنسبة (97.8%) عند بكليت الكبير وعند زاوية الميلان .وظهر من الدراسة أن معدل عدد نسلت على طول القناة يزداد بازدياد الفيض الحراري وذلك لان درجة حرارة المائع الظاهرية سوف تزداد كلما تقدم الجريان إلى نهاية القناة وبذلك فان معامل انتقال الحرارة يزداد. تبين من الدراسة ان في حشوة الفولاذ يكون انتقال الحرارة بالتوصيل هو الغالب منه بالحمل في حين يكون في حشوة الزجاج انتقال الحرارة بالحمل ألقسري الطباقي والذي يكون اقل عدد نسلت سجل مقداره (Nu=3.8) عندما يكون الأنبوب أفقي واقل فيض حراري واقل بكليت.الكلمات الدالة: حمل قسري، قناة دائرية أفقية ومائلة، هواء، كريات زجاجية، كريات فولاذية

DETERMINATION OF THE TEMPERATURE DISTRIBUTION THE PERFORATED FINS UNDERNATURAL CONVECTION

Raid R. Jasim; Thamir Kh. Ibrahim; Dr. Aziz M. Mhamuad

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 62-77

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 (100x270 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.

THERMODYNAMIC MODEL FOR HIGH PRESSURE PHASE BEHAVIOR OF CARBON DIOXIDE IN SEVERAL PHYSICAL SOLVENTS AT DIFFERENT TEMPERATURES

Arkan Jasim Hadi; em A. Karim; Dr. Abdul Mun

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 32-49

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.

DESIGN THREE PHASE OVERCURRENT RELAYS

Mohammed Y. Suliman; Amer M. Kado

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 78-89

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.

NUMERICAL STUDY OF NON-DARCIAN NATURAL CONVECTION HEAT TRANSFER IN A RECTANGULAR ENCLOSURE FILLED WITH POROUS MEDIUM SATURATED WITH VISCOUS FLUID

Ahmed Tawfiq Ahmed; Khalaf Ibraheem Hamada; Mahmood H. Ali

Tikrit Journal of Engineering Sciences, Volume 15, Issue 2, Pages 90-111

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 ( ) which is in the tall layers region at medium Rayleigh number ( ), 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).