volume-03-Issue 2 (2011)
Latest Articles
Heating of Subcooled Refrigerants Flowing inside Porous Tubes Study of Heat Transfer: CO2 Case Study
IJTEE, volume-03, Issue 2 (2011) , PP 121 - 124
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.010
by M. Tarawneh, A. Alshqirate, M. Hammad from Department of Mechanical Engineering, The Hashemite University, Zarqa, Jordan, Al-Balqa' Applied University, Jordan, University of Jordan, Amman, Jordan
Abstract: Experimental study for the heat transfer characteristics in a porous tube was conducted in this work. The tubes were filled with sand beads. Three different particles mean diameters were used, (dm = 5.15 mm, 3.18 mm, 2.03 mm). Liquid CO2 flowed inside tubes placed in laboratory conditions. The tube out wall temperature in 32 points with longitudinal steps was measured. The pressure at inlet was also measured with the rate of the flow of the gas. Heating tube exit was saturated liquid conditions. Results of these experiments were used to calculate the inside tube heat transfer coefficient. An analytical investigation besides the experimental work was carried out for the heating of the sub cooled CO2 liquid as a single-phase refrigerant. An empirical correlation for the coefficient of convectional heat transfer coefficient was formulated as non-dimensional relation: Nude = 0.19 * (Rea) 0.35 (PR) 0.4 (ε) -1.39 A comparison between experimental results and that obtained by this developed correlation was carried out. Comparison also was conducted between correlated results and those calculated using the correlation found in Mills 1995, for flow of liquids in porous tubes. The results of this research showed that for heating processes the proposed correlations were proved to possess low deviations. The deviation from the experimental results reached a maximum value of about 4.7 %. This work can enhance the calculations of heat flux of liquid flowing inside porous media, and can help in the design procedure and practical applications of heat exchangers. read more... read less...
Keywords: Heating, Porous media, Convection heat transfer, R744
Theoretical Analysis of Solar Distillation Using Active Solar Still
IJTEE, volume-03, Issue 2 (2011) , PP 113 - 120
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.009
by Omar Badran from Mechanical Engineering Dept, Faculty of Engineering Technology, Al-Balqa Applied University, Amman, Jordan
Abstract: The performance of active single slope solar still using different operational parameters is studied theoretically and compared with the experimental data for validation purposes, to find out best factors enhancing still productivity. The thermal performance of a single slope solar still coupled with collector is evaluated through implementing the following effective parameters a) different insulation thicknesses of 1, 2.5 and 5 cm, b) solar intensity, c) overall heat loss coefficient d) effective absorptivity and transmissivity, and e) temperature differences between the still cover and water and f) wind speed. It can be concluded from this study that active solar stills can be one of the options for enhancing the productivity of stills, while wind speed and insulation thickness can contribute to the enhancement of the overall yield. read more... read less...
Keywords: Still Performance, Solar still. Solar Energy, Active Solar Systems
Mass and Number Concentration and Size Distribution of Particles Emitted from Diesel Engine
IJTEE, volume-03, Issue 2 (2011) , PP 109 - 112
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.008
by Elzbieta Jankowska from Central Institute for Labour Protection – National Research Institute, Warsaw, Poland, 00-701
Abstract: This paper presents results of research of mass and number concentrations and size distribution particles emitted as Diesel exhaust fumes (DEF). The parameters of fine particles were determined with the gravimetric method (with PCIS samplers and microbalance METTLER TOLEDO type UMX2) and optical methods (DUST-TRAK, P-TRAK, GRIMM, SMPS). Researchers were carried out during the simulation of three 4-hours periods possible exposure of workers to DEF in a garage with switch-on and switch-off Diesel engine located in different positions. Investigations were also done in atmospheric air close to garage before and after measurements performed in the garage. read more... read less...
Keywords: Diesel exhaust, concentration, ultrafine particles, size distribution
Residential Building Walls and Environment in Amman, Jordan
IJTEE, volume-03, Issue 2 (2011) , PP 101 - 107
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.007
by S. J. Sulaiman, N. Beithou from Department of Mechanical Engineering, Applied Science University, Amman 11931, Jordan
Abstract: Jordan has a moderate weather conditions which is overwhelmingly dry. Winter months, December, January and February usually have cold spells with rain, wind and occasional snow. Residential buildings are well built with an outer white stone layer on walls and relatively well sealed windows. Most houses are fitted with central heating systems and water heating using Diesel fuel fired boilers. The high cost of fuel renders limited and intermittent use of the space heating system or as an alternative, the use of flu-less paraffin and gas fired heaters. This in addition to cooking and other occupant activities cause the inside environment to become unhealthy and uncomfortable in winter when ventilation is kept to its minimum. Dampness often leads to Mold growth on cold surfaces of walls and ceiling. The present study is experimental with some theoretical analysis of walls thermal properties in an attempt to reach some solutions. The results indicates that insulation of walls plus some means of ventilation with heat recovery can actually save energy, improve inside air quality and avoid moisture. read more... read less...
Keywords: Building walls, Air quality, Insulation, Energy, Moisture, Ventilation.
Experimental Study of Emissions and Performance of Internal Combustion Engine Fuels
IJTEE, volume-03, Issue 2 (2011) , PP 95 - 100
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.006
by Moh’d Sami Ashhab, Mahmoud Abu-Zaid, Odai Baqaeen, Maraam Khdair, Eyas Adel from Department of Mechanical Engineering, The Hashemite University, Zarqa 13115, Jordan, Department of Mechanical Engineering, Mutah University, Mutah, Jordan
Abstract: Experimental study of 8 different internal combustion fuels is conducted. The 8 fuels are: octane 90, octane 95, blend of 10% methanol & 90% octane 90, blend of 10% methanol & 90% octane 95, blend of 20% methanol & 80% octane 90, blend of 20% methanol & 80% octane 95, blend of 30% methanol & 70% octane 90 and blend of 30% methanol & 70% octane 95. A dynamometer setup is used to conduct the experiments and the emissions and torque at different speeds were measured. The efficiency, power and specific fuel consumption were calculated. The experimental results are represented graphically from which the advantages and disadvantages of each fuel relevant to environment and performance are extracted. The best fuels for internal combustion engines are recommended read more... read less...
Keywords: Emissions, Fuel, Internal Combustion Engines
Design and Fabrication of Auto Air Conditioner Generator Utilizing Exhaust Waste Energy from a Diesel Engine
IJTEE, volume-03, Issue 2 (2011) , PP 87 - 93
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.005
by Khaled AlQdah, Sameh Alsaqoor , Assem Al-Jarrah from Faculty of Engineering, Mechanical Engineering Department, Tafila Technical University, 66110, Tafila , Jordan, Faculty of Engineering, Engineering Chemical Industries Department, Tafila Technical University, Tafila , Jordan
Abstract: In this investigation analysis and design of an automobile air conditioner was made by utilizing the available diesel engine exhaust waste energy to provide the required heat for the generator. Because automotive air conditioning is one of the most equipment that heavily uses CFC compounds, and the leakage of CFCs from such air conditioners affect the environment, the absorption cycle was found to be an ideal option. Cooling load for the automobile has been estimated and found to be within acceptable ranges which are about 1.37 TR. The reported results show that the COP values directly proportional with increasing generator and evaporator temperatures. Measured COP values of the proposed model varied between 0.85 and 1.04. The generator was designed and fabricated for optimal performance and could be rapidly transfer to the industrial applications, The system was found to be applicable and ready to produce the required conditioning effect without any additional load to the engine The proposed system decreases vehicle operating costs and environmental pollution caused by the heating system as well as causing a lower global warming. Simple experiments were carried out to examine the performance of the generator heat shown the benefit of exhaust gases as an alternative heating source. read more... read less...
Keywords: Generator, Absorber , COP, Waste Energy, Cooling Load; Aqua- ammonia
Potential of One-Axis and Two-Axis Tracking Photovoltaic Systems
IJTEE, volume-03, Issue 2 (2011) , PP 81 - 85
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.004
by A. Al Tarabsheh, I. Etier from Electrical Engineering Department, The Hashemite University, 13115 Zarqa, Jordan
Abstract: This paper explores the potential of solar energy generation in the area of The Hashemite University in Jordan (32.05_N, 36.06_E) by investigating the optimal inclination and azimuth angles of photovoltaic (PV) modules for every hour, day, month, and of the whole year. The object of this study is to maximize the annual energy production of PV systems by tracking the changes of sun's position in the sky north-to-south and east-to-west. Hourly, daily, monthly, and annually global radiation averages are simulated using the METEONORM comprehensive meteorological software and then analysed using the MATLAB™ software. This study shows that the one-axis PV tracking system about the inclination axis increases the energy yield of 5.87% compared to the fixed surfaces (azimuth angle=0° and inclination angle=30°) , while the one-axis PV tracking system about the azimuth axis increases the energy yield of 20.12% compared to the fixed surfaces. On the other hand, the two-axis PV tracking system about both the inclination and azimuth axes increase the energy yield of 30.82% compared to the fixed surfaces. read more... read less...
Keywords: One- and Two-axis Tracking, METEONORM, Solar Energy
Correlation between the Bulk Flow Hydrodynamics, Wind Shear Stress and Evolution of the Surface Waves
IJTEE, volume-03, Issue 2 (2011) , PP 73 - 79
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.003
by Mamoun A. M. Janajrah, Omar O. Badarn from Mechatronics Engineering Department, Al-Balqa Applied University, P.O. Box 15008, Amman, Jordan, Mechanical Engineering Department, Al-Balqa Applied University, Amman, Jordan
Abstract: Wind generated surface waves is described as when the wind blows over the water surface and its momentum transfers through the surface to the bulk and generates perturbations throughout. The appearance of the surface waves starts if the disturbing effects due to the action of wind shear stress and induced bulk flow perturbations exceed the effect of restoring forces of gravity, capillary, and viscous forces this occurs as the flow transition from laminar to turbulent occurs. Based on the above description of wind generated surface waves the characteristics of the surface waves depend on strength of the induced bulk perturbations, wind shear stress and the physical properties of the surface. The correlation between evolution the surface waves and the first two factors are discussed in this paper, however the effect of the physical properties of the water surface will discussed in a separate paper. It was found that -irrespective of the wind speed -the waves cannot be generated under the effect of wind action until the strength of the induced bulk flow perturbations become significant and when the laminar-turbulent flow transition occurs. The evolution of the bulk flow parameters under effect of wind action (such as flow velocity, vorticity, swirling strength, shear strength, velocity vector angle) as the wind attains different orders were obtained using PIV system. read more... read less...
Keywords: PIV, surface waves, flow hydrodynamics
An Optimal Two-Dimensional Geometry of Flywheel for Kinetic Energy Storage
IJTEE, volume-03, Issue 2 (2011) , PP 67 - 72
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.002
by Mofid Mahdi from Department of Mechanical Engineering, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
Abstract: The consumption of energy is increasing drastically. The available resources of energy are limited therefore; the search of new sources is a vital issue. This has to be done with efficient energy consumption and saving. A flywheel may provide a mechanical storage of kinetic energy. A capable flywheel must have a very high rotational speed which may lead to a high stresses. The stress state relies on the flywheel material properties, geometry and rotational speed. On the other hand, the stored kinetic energy relies on the mass moment of inertia and rotational speed. This paper considered three solid flywheel disk profiles that are constructed using functions of cubic splines. Using FEM, the cubic splines parameters are analyzed systematically to seek a maximum stored kinetic energy per unite mass. Subjected to maximum permissible effective stress, favorable flywheel disk profiles were achieved. All FEM computations were carried out using ANSYS. read more... read less...
Keywords: Flywheel Profile , Energy Storage, FEM, Stresses, Cubic Splines.
Implementation of Solar Technologies in the Development of Rural, Remote and Sub urban Communities
IJTEE, volume-03, Issue 2 (2011) , PP 59 - 66
Published: 27 Jan 2011
DOI: 10.5383/ijtee.03.02.001
by N. M. Khattab, H. Soliman, M. Metias, I. El-Seesy, E. Mettawee, E. El-Shenawy, M. Hassan from Solar Energy Department, National Research Center, Giza, Egypt, 12622
Abstract: This case study describes a model household in which a number of simple solar technologies are utilized to provide for the daily household needs of electricity, clean water, cooling and heating. The model was named ―Solar Home‖. A ―Solar Home‖ is primarily suited to rural, remote and sub urban low-income communities that suffer from lack of access to grid electricity and clean quality water. However, with the increased demand on energy in urban communities connected to grid electricity, the ―Solar Home‖ can serve as a practical solution in the near future. The case study presents the results of the studies carried out on a pilot scale Solar Home project built in the Solar Energy Department, NRC, Egypt. The solar system designs used in the pilot Solar Home project are practical, easy to install and maintain, as well as inexpensive. The systems would serve two purposes domestic services and some income generating activities. The case study discusses the performance of the selected solar systems under actual climatic conditions of Egypt, their costs. The case study will detail recommendations for the optimum implementation of the suggested systems and the needed training to use those systems. Finally, the case study will list some of the lessons learned and the challenges faced during implementation and operation. read more... read less...
Keywords: Solar Home, Domestic Solar Systems, Generating Activities systems, Costs