• Issue 1 (2014)
• Issue 2 (2014)

Some Aspects of the Rheological Behaviour of Coal Water Slurries

IJTEE, volume-08 , Issue 2 (2014), PP 103 - 107

Published: 20 Nov 2014

DOI: 10.5383/ijtee.08.02.006

by Sunita Panda, R.K. Swain from Sunita Panda, R.K. Swain

Abstract: Initially coal-slurry fuels were based on coal-oil mixtures. Now the emphasis is largely on coal-water fuels. Since most of the studies have been done with coals available in the western countries having low ash content, an attempt has been made in this paper to study some aspects of the rheological behaviour of coal slurries prepared out of coals having high ash content. Crisis in the volatile oil markets experienced in the seventies have promoted renewed interest in coal-based fuel technologies. Coal-slurry fuels have emerged as viable technical alternatives for oil and gas in utility and industrial boilers. Despite current low prices and the abundance of oil, concerns over its long-term availability and price, as well as strategic considerations make coal-slurry technology attractive. In this paper an empirical relationship has been established among apparent viscosity and volume fraction of solids for coal having high ash content. read more... read less...

Keywords: Oil agglomeration, froth flotation, apparent viscosity, HAAKE rotational viscometer

Application of Taguchi’s Methods for Optimizing Organic Rankine Cycle for Recovering Low Grade Industrial Waste Heat

IJTEE, volume-08 , Issue 2 (2014), PP 91 - 101

Published: 20 Nov 2014

DOI: 10.5383/ijtee.08.02.005

by Umesh Kumar, Munawar N. Karimi from Jamia millia Islamia, New Delhi, India, 110025

Abstract: This research attempts the optimization of Organic Rankine Cycle (ORC) by Taguchi’s robust design methods for generating electricity from industrial waste heat. Experimental results and data from previous researches is used to assign the relative importance of parameters. Parameters selected are waste stream temperature, waste stream flow rate, type of refrigerant and turbine speed. Optimum combination of these control parameters is obtained by using Taguchi’s techniques. Individual effect of parameters on the performance of Organic Rankine Cycle is calculated. Interaction effect of parameters on the performance of ORC is also calculated. A percent effect of individual parameters on performance is estimated by using ANOVA. Using this procedure, an optimal cycle can be obtained for maximum efficiency within available sources. read more... read less...

Keywords: Electricity generation; Waste heat recovery; Optimization; Taguchi's method; Organic Rankine cycle; ANOVA

Modeling and Simulation of the Drying of Beech Timber (Fagus sylvatica) Using Oscillating Regimes

IJTEE, volume-08 , Issue 2 (2014), PP 83 - 90

Published: 20 Nov 2014

DOI: 10.5383/ijtee.08.02.004

by Merlin Simo Tagne, Yann Rogaume, André Zoulalian from Douala Higher Institute of Technology (DIT), Douala, Cameroon, PO Box 1623 b University of Lorraine, LERMaB, ENSTIB, Epinal, France, PO Box 1041, 88051 Epinal cedex 9

Abstract: This paper represents a numerical study of the massive (60mm) and thin (38mm) wood drying using oscillating drying regimes applied on beech timber (Fagus sylvatica). All thermo-physical properties relative of studied wood is taken from the literature on appropriate experiments. We showed that Luikov’s model can be used to predict temperature and moisture content evolutions using oscillating regimes. First numerically tests on 60mm timber wood consists in increasing and decreasing alternation of the drying parameters (temperature), at the rising 12-15°C and at the descent 10- 12°C, every alternation being higher than the precedent with 2-4°C. Second numerical test consists to oscillate the values of equilibrium moisture content with the oscillation amplitudes of ±10% and ±20% at the frequencies of 6hours. These practical experiments are detailed in the literature. Luikov’s model gives satisfactory results, according to the experiments obtained in the literature. But, convective transfer coefficients are function of each experiment and we observed a short difference between oscillation amplitudes of ±10% and ±20% on moisture content evolution. Thus, Luikov’s model can be a tool to study oscillation drying timber in order to reduce consumption of energy during the drying process. read more... read less...

Keywords: Drying, Heat and Mass Transfer, Luikov’s Model, Simulation, Oscillating Regimes, Beech Wood.

Thermoeconomic Analysis of Multi-Stage Thermoelectric Cooler

IJTEE, volume-08 , Issue 2 (2014), PP 77 - 82

Published: 19 Nov 2014

DOI: 10.5383/ijtee.08.02.003

by Sudhanshu Sharma, V. K. Dwivedi, S. N. Pandit from Department of Mechanical Engineering, Mewar University, Chittorgarh, Rajasthan, India, 312901, Department of Mechanical Engineering, Galgotias College of Engineering & Technology, Uttarpradesh, India, 201306, Department of Mechanical Engineering, Noida Institute of Engineering & Technology, Uttarpradesh, India, 201310

Abstract: In this paper a two stage thermoelectric cooler which has total 50 elements out of which 30 elements are on hotter side and 20 elements are on colder side, analyzed on the basis of the principles of thermoeconomics. Exergy destruction has been used to calculate the second law efficiency. Then the exergy has been coupled with unit cost of exergy to calculate the cost of refrigeration produced. The model has been analyzed for a particular life cycle of thermoelectric cooler (TEC) where the operating conditions change with the variation in cold side and hot side temperatures. Two cases have been considered. In first case the cold side temperature is varied with hot side temperature maintained as constant. In second case hot side temperature is varied with cold side temperature maintained as constant. The analysis shows that on the basis of thermoeconomics the first case is favorable but the comparison on the basis of coefficient of performance, rate of refrigeration and second law efficiency show that the second case is favorable. read more... read less...

Keywords: Thermoelectric cooler, Thermoeconomic, Exergy, COP, Rate of refrigeration, Second law efficiency

Crumb Rubber Effect on Acoustic Properties of Self- Consolidating Concrete

IJTEE, volume-08 , Issue 2 (2014), PP 69 - 76

Published: 19 Nov 2014

DOI: 10.5383/ijtee.08.02.002

by Malek Jedidi, Ali Boulila, Omrane Benjeddou, Chokri Souss from Institut Supérieur des Etudes Tecnologiques de Sfax, Département de Génie Civil, B.P.88, 3099 Sfax, Tunisia, Université de Tunis El Manar, Ecole Nationale d’ Ingénieurs de Tunis, Laboratoire de Génie Civil, B.P.37,Tunis Belvédère, 1002,Tunisia, Université de Sfax, Faculté des sciences de Sfax, Laboratoire de Géoressources, Matériaux, Environnement et Changement Globaux, B.P.1171 Sfax, Tunisia

Abstract: Several researches have been conducted to find a practical and environmentally sound solution of the problem of scrap tires. In this context, an experimental study was conducted to provide more data on the effect of crumb rubber on the acoustic properties of self-consolidating concrete SCC. To this end, Parallelepiped and cylindrical specimens were prepared by varying the proportion of crumb rubber with percentages of 0 %, 10 %, 20 % and 30 % of the volume of gravel. Properties such standardized level difference, sound absorption at different frequency and noise reduction were investigated. The results showed that the sound absorption and noise reduction coefficient were increased according to the increase of the percentage of crumb rubber. The self-consolidating concrete rubber SCCR has better acoustic properties in comparison with SCC. read more... read less...

Keywords: Crumb rubber, Self-consolidating concrete, Standardized level difference, Sound absorption, Noise reduction, Sound transmission class.

ENGREF-FCAP “Flying Wood’’ Method to Characterize Unknown Central Africa Tropical Woods Relative of Their Drying

IJTEE, volume-08 , Issue 2 (2014), PP 63 - 68

Published: 19 Nov 2014

DOI: 10.5383/ijtee.08.02.001

by Merlin Simo-Tagnea, Romain Rémond from Douala Higher Institute of Technology (DIT), Douala, PO Box 1623, Cameroon, University of Lorraine, LERMAB, ENSTIB, Epinal, PO Box 1041, F-88051 cedex 9, France

Abstract: When we want to opposite excessive exploitation of some species of wood in the tropics, it is important to characterize unknown woods with intention of their valorization. This is most urgent than in the majority of these countries, only some species are highly exploited and the species less valorized are destroyed during the researches of known species in the forests. ENGREF-FCAP ‘’flying wood’’ method is an alternative to classify unknown woods according to their drying. This method permits us to evaluate deformations of wood sample during a dissymmetrical drying and to estimate also evolution of their drying kinetic. The radius of the curvature of samples and drying kinetic permit us to compare the attacks of the drying air conditions on the samples. When these attacks are capable to destroy the quality of wood, a review of these conditions permits to want favorable conditions until we obtained the drying table of unknown woods read more... read less...

Keywords: ENGREF FCAP ‘’flying wood’’ method- Tropical woods- Drying- Characterization- LERMAB

Development of a Simulation Program to Optimise Process Parameters of Steam Power Cycles

IJTEE, volume-08 , Issue 1 (2014), PP 55 - 61

Published: 27 Jul 2014

DOI: 10.5383/ijtee.08.01.007

by Harshal D Akolekar, P Srinivasan, Jagat Sesh Challa from Department of Mechanical Engineering, Birla Institute of Technology & Science, Pilani, India, 333031 Department of Computer Science & Information Systems, Birla Institute of Technology & Science, Pilani, India

Abstract: Conventional coal-based thermal power plants have an average overall efficiency in the range of 35-38 %. Any increase in the percent efficiency of these power plants, is subjected to constraints posed by maximum and minimum temperatures, which are restricted by the creep property of materials and ambient temperature, respectively. Hence, an increase of efficiency beyond certain limits is not possible without optimizing the process parameters associated with reheat and regenerative cycles. In this work, an attempt is made to optimize reheat and regenerative cycle process parameters such as, reheat pressure, tapping pressure of bled steam, and mass fraction of bled steam, in order to achieve maximum cycle efficiency. The optimization of the process parameters was achieved by developing a simulation program using Microsoft Visual Studio. This program takes into account isentropic efficiencies of turbines and pumps and pressure drop in the boiler, and it can be used to simulate the optimum operating conditions of multi-stage reheat & regenerative cycle based thermal power plants. A comparison between the efficiencies of eight kinds of steam power cycles, at optimized conditions, has been made for different boiler pressures and steam temperatures at the turbine inlet. This comparison can aid power plant designers in choosing appropriate steam power cycles for a given set of operating conditions. It is observed that the results obtained from the program, such as, the optimum reheat pressures for two stage reheat cycles and optimum bled steam tapping pressures for two stage regenerative cycles are in good agreement with the published literature. read more... read less...

Keywords: Reheat cycle, Regenerative cycle, Process parameters, Optimisation, Efficiency, Power plant

Experimental Study and Performance Analysis of Ceramic Packing Cooling Tower Using Taguchi Method

IJTEE, volume-08 , Issue 1 (2014), PP 45 - 53

Published: 27 Jul 2014

DOI: 10.5383/ijtee.08.01.006

by Ramkumar Ramakrishnan, Ragupathy Arumugam from Department of Mechanical Engineering, Annamalai University, Annamalai Nagar-608002, Tamilnadu, India

Abstract: Deterioration of the packing material is a major problem in cooling tower. In this experimental study, ceramic tile is used as packing material. The experimental study was conducted in a forced draft cooling tower. Cooling tower operating parameters were optimized using Taguchi approach. The application of Taguchi method is assessing maximum cooling tower effectiveness for the Forced draft counter flow cooling tower using ceramic packing. An experimental study has been carried out for Taguchi’s L9 orthogonal array. According to Orthogonal array the trail was performed under different inlet conditions of flow rate of water, air and Inlet water temperature. Signal-to noise ratio (S/N) and regression were carried out in order to determine the effects of process parameters on cooling tower effectiveness. Finally, confirmation tests verified this reliability of Taguchi method for optimization of forced draft counter flow cooling tower performance with sufficient accuracy. Confirmation experiment was d o n e u sing optimum combination showed that cooling tower effectiveness was found by experiment is closer to the predicated value read more... read less...

Keywords: optimization, Cooling tower, ceramic packing, performance, Taguchi Method, Regression

Numerical and Experimental Study of Flow Structure and Cooling Behavior of Air Impingement on a Target Plate

IJTEE, volume-08 , Issue 1 (2014), PP 33 - 43

Published: 26 Jul 2014

DOI: 10.5383/ijtee.08.01.005

by Adnan A. Abdul Rasool, Jirunthanin V., F. A. Hamad from Mech. Eng. Dept, college of Engineering, Al-Mustansiriya University, Baghdad, Iraq School of Science & Engineering, Teesside University, Middlesbrough, TS1 3BA, U

Abstract: Numerical and experimental study is carried out to investigate flow structure and heat transfer of air jet normally impinging on a flat plate. Three orifices of 5, 10 and 20 mm diameters and Z/d ratios in the range of 2 to 8 were used. The numerical simulations were performed with the ANSYS FLUENT for steady, three-dimensional, incompressible, and turbulent flow from the jet. The comparison of CFD predictions with experimental results show that a good agreement of the average Nusselt number, the pressure coefficients distributions, radial velocity distributions of the fee jet. read more... read less...

Keywords: CFD simulation, Nusselt number, jet flow, Wall jet velocity

A Study of Spark Ignition Engine Fueled with Methanol and Ethanol Fuel Blends with Iso-Octane

IJTEE, volume-08 , Issue 1 (2014), PP 25 - 31

Published: 26 Jul 2014

DOI: 10.5383/ijtee.08.01.004

by Sandeep Kumar Kamboj, Munawar Nawab Karimi from Mechanical Engineering Department, Jamia Millia Islamia Jamia nagar, New Delhi 110025, India

Abstract: Alternative fuels are derived from resources other than petroleum. The benefit of these fuels is that they emit less air pollutant compare to gasoline and most of them are more economically beneficial compared to oil and they are renewable. In addition, ethanol has higher evaporation heat, octane number and flammability temperature therefore it has positive influence on engine performance and reduces exhaust emissions. In this study, the effects of unleaded iso-octane, unleaded isooctane–ethanol blend (E5) and iso-octane-methanol (M5) blends on engine performance are investigated experimentally in a single cylinder fourstroke spark-ignition engine at a constant 8 Kg load. The engine speed was changed from 1100 to 1800 rpm. The results of the engine test showed that ethanol addition to unleaded iso-octane increases the value of IP, FP and IMEP with E5 fuel. The results also showed that the indicated power, brake power, friction power, indicated mean effective pressure, torque, exhaust temperature, and thermal efficiency increases with the increase in engine speed at a constant load of 8 Kg for E5, M5 and isooctane fuels. Thermal efficiency was maximum for E5 fuel (38.13%) at a speed of 1750 rpm. read more... read less...

Keywords: Thermal efficiency, volumetric efficiency, exhaust temperature, indicated power, bsfc, engine speed

Design and Simulation of a Solar Tracking System for Optimum Energy Absorption

IJTEE, volume-08 , Issue 1 (2014), PP 17 - 24

Published: 14 Jun 2014

DOI: 10.5383/ijtee.08.01.003

by Hussain A. Attia, Beza Negash Getu from Electronics and Communications Engineering Department, American University of Ras Al Khaimah, UAE

Abstract: Nowadays the importance and dependence on solar power source is remarkably increasing as there is a strong need to have clean, cheap and renewable energy compared with other types of energy sources. In this paper, we present a complete design and analysis of an electronic circuit that can be used for optimum solar energy absorption and tracking. The proposed electronic circuit will accurately track the sun light and face the solar panel in the direction of maximum solar energy absorption. The presented design starts with an array of light intensity photo sensors (Light Dependent Resistor (LDR)) followed by a number of processing steps to finally deliver a suitable dc voltage for driving a dc motor, which is required to move and align the solar panel to the direction of maximum solar intensity. There is a continuous controlling and tracking functions using the light intensity information from the three photo sensors. The presented design is implemented using an Op-Amp and general purpose electronic components without a requirement to any special purpose electronic item for tracking. The design also provides an ability of monitoring the various stages using a number of LEDs distributed along the parts of the electronic circuit. read more... read less...

Keywords: Solar energy, Light dependent resistor, maximum power point tracker, Op-Amp, CMOS, drive circuit, DC Motor

Numerical Study of Heat and Mass Transfer during the Thermal Drying of Tropical Woods

IJTEE, volume-08 , Issue 1 (2014), PP 9 - 15

Published: 08 Nov 2014

DOI: 10.5383/ijtee.08.01.002

by Merlin Simo Tagne from Douala Higher Institute of Technology, Douala, Cameroon, PO Box 1623

Abstract: A sector of utilization and transformation of wood give much money at the countries of the central Africa region. If we want to increase these advantages, it is important to do locally the first and second transformations of wood. Self-control of the wood drying is necessary to ameliorate a wood quality and to preserve an art work doing in wood. In this article, we are modeling a drying of one piece of bete wood (Mansonia altissima) with dimensions are 1m of length and thickness is no more than 25cm. We have used a literature to obtain a mass and heat equations and the thermophysical properties of the present wood. We have considered some thermophysical properties that we are unkempt in the precedent work [1]. We have experimentally obtained a relationship between a density of this wood with a water content. The others thermophysical properties come from the literature [1,2]. We have simulated a wood drying in the constant conditions and in the conditions of the bete drying table established by CIRAD Organization. A sensibility study is doing to validate a modeling. Then, the present modeling explains temperature, mass fraction of the vapor in air and water content evolutions during the industrial process of drying. This modeling can to be used for to overhaul a drying table of bete wood and the others of tropical woods. This work uses a gaseous pressure can be used to explain the drying with the high temperatures conditions. read more... read less...

Keywords: Drying- Heat and Mass Transfer -Forced Convection-Modeling- Finite Difference-Mansonia Altissima

Effect of Rubber Aggregates on the Thermophysical Properties of Self-Consolidating Concrete

IJTEE, volume-08 , Issue 1 (2014), PP 1 - 7

Published: 14 Jun 2014

DOI: 10.5383/ijtee.08.01.001

by Malek Jedidi, Ahmed Gargouri, Atef Daoud from Department of Civil Engineering, Higher Institute of Technological Studies, B.P.88, 3099 Sfax, Tunisia, University of Tunis El Manar, National Engineering School of Tunis, Civil Engineering Laboratory, Tunis, Tunisia, University of Gabes, National Engineering School of Gabes, 6029 Tunisia

Abstract: In this work, our choice fell on the exploitation of rubber aggregates from used tires. In this context, an experimental study was conducted to provide more data on the effect of rubber aggregates on the thermophysical properties of self- consolidating concrete (SCC). To this end , four sets of rectangular specimens were prepared by varying the proportion of the rubber aggregates with percentages of 0 %, 10 %, 20 % and 30 % of the volume of gravel .Tests on hardened self-consolidating concrete rubber SCCR included measuring the thermal conductivity and the thermal diffusivity by the method of the boxes at steady and determining the specific heat . The results showed that the thermal conductivity and thermal diffusivity were decreased according to the increase of the percentage of rubber aggregates. This decrease was significantly improved thermal performance of the SCCR. read more... read less...

Keywords: Rubber aggregates, Self-consolidating concrete, Thermal conductivity, Thermal diffusivity, Specific heat.