Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
38
2
2011
Rheological Study of Paraffin-Water Mixture in Horizontal Rectangular Channel
93-110
Abdelaziz
Mimet
Laboratoire d'Energetique , Mécanique des Fluides et Sciences des Matériaux, Faculté des Sciences / BP 2121 -93000, Tétouan, Maroc
Philippe
Haberschill
CETHIL UMR 5008 / INSA - UCBL - CNRS / Bat Sadi Carnot, 20 Avenue Albert Einstein, 69621, Villeurbanne Cedex, France
Mohamed Najib
El Boujaddaini
CETHIL UMR 5008 / INSA-UCBL-CNRS / Bat Sadi Carnot, Villeurbanne,France; Laboratoire d'Energetique , Mécanique des Fluides et Sciences des Matériaux, Faculté des Sciences / BP2121-93000,Tétouan, Maroc
The mathematical modeling of liquid-solid flows is very complex because the solid particles distribution in the carrier liquid is heterogeneous or even when moving beds occurs. In this paper, a mathematical modelling and a numerical simulation of the flow behavior of the paraffin slurry in a horizontal rectangular channel is presented. The pressure drop was presented and analyzed. The diffusion equation was solved, and the concentrations of suspended solid particles in the mixture have been given for several values of the mixture’s average velocities.
Non-Newtonian Fluid Flow around Ellipsoidal Particles
111-121
Yazan
Taamneh
Department of Aeronautical Engineering, Jordan Univesity of Science and Technology, Irbid,
Jordan
Steady axisymmetric laminar flow of incompressible power-law fluid around ellipsoidal particle is studied numerically. The power law index are ranged over 0.5 ≤ n ≤ 1.5 i. e., covering both shear-thinning and shear-thickening behavior. Numerical results are presented for an ellipsoid of axis ratio a/b = 2 and the limiting case of a sphere at various Reynolds number between 20 and 200. Special consideration is given to the effect of power law index on the skin friction coefficient, separation angles and drag coefficient. The streamline plots showing the nature of flow and the wake structure are presented. It was found that the total drag coefficient around the ellipsoid is strongly governed by the power law index as well as the Reynolds number. It was observed that the separation appears at lower power-law index (shear thinning) and disappear at higher power law index (shear thickening). Separation angels and drag coefficient for special case of a sphere was found to be in good agreement with previous experimental results and with the standard drag curve.
Control of Separation Flow in Sudden Enlargement
122-143
A.
Abdel-Fattah
Department of Mechanical Power Engineering, Faculty of Engineering Menoufiya University, Shebin El-Kom
In the present paper, an injection flow in separation zone in sudden enlargement has been studied experimentally and numerically. The injected flow is achieved through twelve slots placed around the inner side wall of the step. The static pressure is measured and calculated along the wall of sudden enlargement for different values of injection ratio and injection flow angles. The average heat transfer variation with injection Reynolds number (Rej) has been obtained for different values of the injection flow angle. The mean velocity vector, velocity contours, turbulent kinetic energy contours and temperature contours are found. The flow Reynolds number of injected flow in this study is found to vary between 320 and 840, the flow Reynolds number for the main flow is 5895 to 8450 at injection flow angles of 0, 15, 30, 45 and 60°. The results indicate that, the pressure recovery coefficient increases by decreasing the injection ratio and increasing the injection flow angle. The average heat transfer coefficient increases as both injection Reynolds number and injection flow angle increase. The numerical results show that two recirculation zones generate behind the step between the injected flow and the main flow. The size of these recirculation zones decreases by increasing the injection flow rate. The turbulent kinetic energy increases within the region between the recirculation zone and main zone. On the contrary, it decays by injecting flow in the recirculation zone. The zone for higher value of flow temperature decreases by injecting flow in the recirculation zone, and this zone increases as the injection flow rate increases. The comparison between the experimental and the numerical results using the k-ε model with Leschziner and Rodi correction show a fairly good agreement.
Air-Conditioning Cooling Load and Petrol-Ethanol Mixtures in Engines Impact on Global Climate Change
144-152
J. A.
Olorunmaiye
Department of Mechanical Engineering, University of Ilorin, Ilorin, Nigeria
D. O.
Ariyo
Department of Mechanical Engineering, University of Ilorin Ilorin, Nigeria
A. D.
Ogunshola
Department of Mechanical Engineering, Ladoke Akintola University of Technology, Ogbomosho, Nigeria
K. R.
Ajao
Department of Mechanical Engineering, University of Ilorin, Ilorin, Nigeria
The climate is one of the factors on which the energy required to cool a building depends. Hourly dry-bulb temperature and relative humidity data for fifteen years (1978 − 1992) were obtained for Ilorin and Ikeja. From statistical analysis of the data, it was found that the mean dry bulb temperature and the 1, 2.5 and 5 % design dry-bulb temperature used for air-conditioning cooling load calculation were higher than the corresponding values published in 1974 from statistical analysis of weather data for the fifteen year period of 1951−1965. This shows that more energy will be required for cooling buildings if the trend of global warming continues. One way to reduce global warming is by using bio-fuels. A four stroke spark-ignition engine was run on pure gasoline, 5 % ethanol to 95% gasoline, 10 % ethanol to 90 % gasoline, 15 % ethanol to 85 % gasoline and 20 % ethanol to 80 % gasoline. When the engine ran on pure gasoline, it developed a maximum torque of 10.7 Nm, a brake power of 3141.6 W and a brake thermal efficiency of 25.91 %. Each of these performance parameters reduced as the percentage of ethanol increased. For the 20 % ethanol to 80 % gasoline blend the corresponding values of the performance parameters obtained were 10.2 Nm, 2827.44 W and 21.75 %. Even though the performance of the engine declined as the percentage of ethanol increased, the emission of less green house gases is enough motivation to use bio-fuels.
Investigation of Air Flow Rates Effect in Presence of Heated Obstruction Within Room
153-166
Abduljabbar
Ahmed
Mechanical Engineering Department, Faculty of Engineering and Technology Jamia Millia Islamia, New Delhi, India
Mukhtar
Ahmad
Mechanical Engineering Department, Faculty of Engineering and Technology Jamia Millia Islamia, New Delhi, India
Abdur
Rahim
Department of Mechanical Engineering, Faculty of Engineering & Technology, Jamia Millia Islamia, New Delhi - 110025, India
This study reports the results of a numerical investigation of threedimensional turbulent buoyant recirculating flow within rooms with heated obstruction. The study involves the solution of partial differential equations for the conservation of mass, momentum, energy, concentration, turbulent energy and its dissipation rate. These equations were solved together with algebraic expressions for the turbulent viscosity and heat diffusivity using k-ε turbulence model by performing simulations on FLUENT 6.3. The CFD method was validated via comparing with the available experimental data. A comparison with experimental results shows good agreement. This means that the present computer code has a good capability to simulate 3D airflow and effect of obstruction within room. The present study demonstrates the flow behavior, thermal distribution and CO2 concentration inside the room in the presence of heat flux obstruction with respect to three values of volume airflow rate. The results show that the efficiency of ventilation (thermal) is less than one hundred percent and become more than one hundred percent when used low ventilation rate. Concentration of CO2 is very often used as an indicator for the control of air flow rate to the building. The concentration of CO2 is high above the obstruction in the occupation zone at low volume flow rate and it reduces with increase in the volume flow rate.
Experimental Investigation of WaterWave Characteristics in aWave Channel
167-178
Mohammed
Faizal
Division of Mechanical Engineering, The University of the South Pacific Laucala Campus, Suva, Fiji
M. Rafiuddin
Ahmed
School of Engineering and Physics, Faculty of Science and Technology, The University of the South Pacific, Suva, Fiji
Chang-Goo
Kim
Division of Mechanical and Information Engineering, Korea Maritime University 1 Dongsam-Dong, Youngdo-ku, Busan 606-791, Korea
Young-Ho
Lee
Division of Mechanical and Information Engineering, Korea Maritime University 1 Dongsam-Dong, Youngdo-ku, Busan 606-791, Korea
A deeper understanding of the water wave characteristics is essential for designing efficient energy extraction devices. An experimental study of the characteristics of waves was performed in a two-dimensional wave channel by varying the mean depth of water and the wave frequency. The orbital motion of particles in water waves has been of interest to researchers from both academic and practical perspectives. This orbital motion, which results from the directional velocities of the particles under waves at different phase positions, was studied with particle image velocimetry (PIV) measurements and compared with theoretical calculations. The kinetic energy and the size of the orbits were found to be larger near the surface and reduce with increasing depth. It was also found that the wavelength reduces with increasing frequency as well as for reducing mean water depths, while the wave height and the wave power increase with frequency (for non-breaking waves). The wave power was found to be the highest for the case of maximum mean water depth in the wave channel.
Stirring of Fluid Particles through a Rotating Helical Pipe of Circular Cross-Section under Fully Developed Flow Condition
179-191
M. A.
Masud
Institute of Natural Science, United International University Dhanmondi
Md. Mahmud
Alam
Khulna University, Khulna
Laminar incompressible viscous flow through a rotating helical pipe has been studied to understand the stirring of the fluid particles over the cross-section of the pipe. The pitch and the curvature affect the mixing property but the most affecting factor is rotation. In this study, the flow has been considered to be driven by a constant pressure gradient force along the center line of the pipe. The problem has been solved numerically using spectral method. To understand the stirring, 360 fluid particles 1° apart are considered at nondimensional radius 0.8.