volume-08-Issue 1 (2014)
IJTEE, volume-08, Issue 1 (2014) , PP 55 - 61
Published: 27 Jul 2014
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
IJTEE, volume-08, Issue 1 (2014) , PP 45 - 53
Published: 27 Jul 2014
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
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
IJTEE, volume-08, Issue 1 (2014) , PP 25 - 31
Published: 26 Jul 2014
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
IJTEE, volume-08, Issue 1 (2014) , PP 17 - 24
Published: 14 Jun 2014
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
IJTEE, volume-08, Issue 1 (2014) , PP 9 - 15
Published: 08 Nov 2014
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 . 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
IJTEE, volume-08, Issue 1 (2014) , PP 1 - 7
Published: 14 Jun 2014
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.