IJTEE, volume-09 , Issue 2 (2015), PP 117 - 126
Published: 13 Jul 2015
by K. Bala Showry, P. Ravinder Reddy, A.V. Sita Rama Raj from DRK Institute of Science and Technology, Hyderabad, India, 500090 Mechanical Engineering Department, CBIT Hyderabad, India, 500075 Mechanical Engineering Department, JNTUH Hyderabad, India, 500085
Abstract: In order to meet the stringent emission standards, significant efforts have been imparted to the research and development of cleaner IC engines. Diesel combustion and the formation of pollutants are directly influenced by the spatial and temporal distribution of the fuel injected. The development and validation of computational fluid dynamics (CFD) models for diesel engine combustion and emissions is described. The complexity of diesel combustion requires simulation with many complex interacting sub-models in order to have success in improving the performance and to reduce the emissions. In the present work, an attempt has been made to develop a multidimensional ax-symmetric model for CI engine combustion and emissions. Later simulations have been carried out using split injection for single, double, and three pulses (split injection) for which commercial validation tool FLUENT was used for simulation. The tool solves basic governing equations of fluid flow that are continuity, momentum, species transport, and energy equation. Using the finite volume method turbulence was modeled by using the RNG K-ɛ model. The injection was modeled using the La Grangian approach and the reaction was modeled using non-premixed combustion which considers the effects of turbulence and detailed chemical mechanism into account to model the reaction rates. The specific heats were approximated using piecewise polynomials. Subsequently, the simulated results have been validated with the existing experimental values. The peak pressure obtained by simulation for single and double is 10% higher than that of the experimental value. Whereas for triple injections 5% higher than that of the experimental value. For quadruple injection, the pressure has been decreased by 10% when compared to triple injection.NOX has been decreased in simulation for single, double, and triple injections by 15%, 28%, and 20%. For quadruple injection NOX was reduced in quadruple injection by 20% to that of triple injection. The simulated value of soot for single, double, and triple injections are 12%, 22%, and 12% lesser than the experimental values. For quadruple injection, the soot levels were almost negligible. The simulated heat release rates for single, double, and triple were reduced by 12%, 18%, and 11%. For quadruple injection, heat release is reduced the same as that of triple injection read more... read less...
Keywords: Split injection, Computational Fluid Dynamics, Start of injection, Duration of injection
EnergyEfficiency Improvements through Optimization of Low Grade Industrial Waste Heat Recovery Organic Rankine Cycle by usingGeneticAlgorithms and Taguchi s Method
IJTEE, volume-09 , Issue 2 (2015), PP 107 - 115
Published: 04 Jul 2015
by Umesh Kumar, Munawar N. Karimi from Department of Mechanical Engineering, Jamia Millia Islamia, New Delhi, India
Abstract: Present work focuses on thermodynamic optimization of Organic Rankine Cycle (ORC) used for waste heat recovery from industries. The effect of variation in operating parameters is studied for three different working fluids. Parameters of the ORC are optimized with thermal efficiency, net work output and exergy destruction rate as the objective functions using genetic algorithm in MATLAB. Optimization of ORC performed by genetic algorithms is compared with that done by Taguchi’s method for the similar set of performance parameters and the same waste heat source. Both the methods revealed results in accordance with each other. ORC shows the optimized thermal efficiency with R-245fa and optimized net work output for R-134a. It is found that performance parameters have significant effect on the performance of ORC. By genetic algorithm the optimum performance can be predicted with good accuracy. read more... read less...
Keywords: Organic Rankine Cycle, Energy Efficiency, waste heat, Genetic algorithms
Design, Construction and Operation of Solar Dryer for Granules and Micros Chips of Manihot esculenta crantz Tuberous Roots
IJTEE, volume-09 , Issue 2 (2015), PP 99 - 105
Published: 05 Jun 2015
by P. Bokungu Efoto, L. Efoto Eale, S. Lukombo Singi and Mahungu Nzola Meso from Department of Physics, Faculty of sciences, University of Kinshasa, Kinshasa, D.R. Congo Scientific Committee for the Research and Development of Biodiversity (CSB), Faculty of sciences, University of Kinshasa, Kinshasa, D.R. Congo International Institute of Tropical Agriculture (IITA), 4163, Av. Haut-Congo, Gombe, Kinshasa, D.R. Congo
Abstract: This study presents the design details and the performance analyses carried out with Eloumah 1, the solar drier of cassava tuberous roots reduced in granules and microchips. Eloumah 1 is composed by a solar collector, a drying chamber and a box of rectangular section that joins the two previous components. In this solar drier the wet agricultural products are dried on the basis of the heat flux buoyancy that is induced by the difference in temperature and humidity in its compartments. Analyses of masses evaporated water of zizila and Obama (TME 419) granules and microchips tuberous roots varieties have been carried out in order to estimate the drying performance of Eloumah 1 and to know the natural laws of the drying process. The results show that Eloumah 1 is able to dry granules and microchips and to reduce their moisture contain to less than 10%. Moreover, it can be established that the drying process is a logistic process because in wet control samples, moisture contain has limited value. Therefore, the drying process cannot extract the free water beyond this limit value. The logistic function adjusts well these data based on the correlation coefficient (R2) and chi square coefficient (χ2). read more... read less...
Keywords: Manihot esculenta crantz, drying process, logistics process, drying speed function
IJTEE, volume-09 , Issue 2 (2015), PP 91 - 97
Published: 05 Jun 2015
by M.R. Guechi, P. Desevaux, P. Baucour, C. Espanet, R. Brunel and M. Poirot from University of Franche-Comté, FEMTO-ST-UMR CNRS 6174, Dept Energy, Belfort F-90000, France INSA Lyon, IMP-UMR CNRS 5223, Villeurbanne F-69621, France
Abstract: The objective of this work is the improvement of the heat dissipation and the cooling of electric motors intended for the traction of vehicles. Two ways of improvement are proposed. The first one consists in replacing the air surrounding the stator windings by resins of higher thermal conductivity. The second way consists in using the spray cooling technique to cool the hottest parts of electric motor, i.e. coil windings. The two solutions are tested independently and simultaneously. Results show that filling the coil windings with resin enables better heat dissipation in the case of basic cooling by free air convection. On the contrary, the lowest temperatures are obtained with traditional coil winding without resin and by using spray cooling. In that case, the liquid part of the spray may infiltrate inside the coil and the evaporation takes place at the hottest point. read more... read less...
Keywords: Electric motor, Thermal performance, Heat dissipation, Windings impregnation, Spray cooling
Turning to Service, Preliminary Study of a Wood Conventional Semi Industrial Dryer and Cost Price of the Wood Drying in the African Tropical Context
IJTEE, volume-09 , Issue 2 (2015), PP 83 - 90
Published: 31 May 2015
by Merlin Simo Tagne, Romain Rémond, Yann Rogaume, André Zoulalian, Eric Mougel from Douala Higher Institute of Technology, PO Box 1623, Douala-Cameroon Association for Research and Promotion of Sustainable Energy in Central Africa (ARPEDAC) University of Lorraine, LERMaB, PO Box 1041-88051, Epinal- France
Abstract: As all apparatus used permanently or not, dryers of wood require a regular maintenance in other that the entry orders are effectively operated in the dryer and these components: interior air, interior wall and wood during the drying. This maintenance also permits to obtain the real values of the measured orders to following very well the drying operation. In this paper, we present the equipment and the calibration of wood semi industrial dryer of the National Higher College of Wood Technologies and Industries (ENSTIB) of the University of Lorraine situated at Epinal-France. These actions are much importance to use this dryer for the serious scientific studies. Then, the results that we have obtained in this dryer are analyzed and validated. Ayous wood (Triplochiton Scleroxylon) is used, because desorption isotherms are well-know and desorption energy is deducted very easily. We have also estimated the appropriated wood waste to bring the energy needed by combustion. An estimation of the cost price of the drying of wood is doing in order to motivate the workers of the domain. read more... read less...
Keywords: Wood dryer, calibration, drying kinetic, enthalpy, cost price, ayous, tropical woods.
IJTEE, volume-09 , Issue 2 (2015), PP 75 - 82
Published: 31 May 2015
by Sunil J. Kulkarni, Jayant P. Kaware from Department of Chemical Engineering, Datta Meghe College of Engineering, Airoli, Navi Mumbai, India, 400708 Bhonsala College of Engineering and Research, Akola, Maharashtra, India, 444001
Abstract: Packed bed adsorption of various pollutants from effluents is efficient and cost effects method. Various factors affecting the removal percentage are initial concentration, flow rate, pH and bed height. Various models can be used to explain the packed bed adsorption. In the current work, the experimental data obtained for packed bed is fitted in the two model equations. Thomas model and Yoon Nelson model were used and the kinetic parameters were computed. Also effect of the factors like initial concentration, flow rate, pH and bed height on these kinetic parameters was studied. It was observed that these factors moderately influence the kinetic parameters. The experimental data was well described by these two models. read more... read less...
Keywords: kinetic model, parameters, capacity, concentration, saturation.
IJTEE, volume-09 , Issue 2 (2015), PP 67 - 74
Published: 02 May 2015
by Mazen Abualtayef, Reem Elghossain, Mahmoud Shatat, Israa Abushaban from Environmental Engineering Department, the Islamic University of Gaza, Gaza, Palestine, Institute of Sustainable Energy Technology – University of Nottingham, Nottingham, NG7 2RD – UK
Abstract: Sustainable energy supply is one of the main challenges that people will face over the coming decades. Biomass can make a substantial contribution to supplying future energy demand in a sustainable way. Currently it is the largest global contributor of renewable energy, and has significant potential to expand the production of heat, electricity and fuels for transport. Municipal solid waste is an enormous renewable resource that has high energy capacity because it contains a high proportion of biomass materials. This kind of sustainable waste management typically called waste-to-energy is critical for reducing the reliance on fossil fuels and non-renewable materials. Waste-to-energy is a reliable and alternative form of energy that has become the basis for many of the most successful solid waste management systems in many countries. Energy recovery from waste is the conversion of waste materials into useable heat, electricity, or fuel through a variety of processes. This study assesses the potential contribution of waste-to-energy facilities to total Gaza peak power demand up to the year 2040 based on three scenarios: incineration, anaerobic digestion and landfill gas recovery. Three dumping sites are distributed along the Gaza Strip, Johr El-deek, Deir El-balah and Rafah. The analysis shows a potential to produce about 1100 MWh per day based on the anaerobic digestion scenario, about 580 MWh per day based on incineration of municipal solid waste scenario, and about 130 MWh per day based on landfill gas recovery scenario. These values accounts to 275%, 145% and 33% of the year 2014 peak electricity demand of 400 megawatt from the three scenarios, respectively. The forecasted results of the three scenarios can be used to design future waste-to- energy facilities in the main cities of the Gaza Strip. The production cost of energy was 7¢/kWh, 5¢/kWh and 17¢/kWhfor incineration, anaerobic digestion and landfill gas recovery scenarios, respectively. read more... read less...
Keywords: Municipal solid waste, Biomass, Waste-to-Energy, Cost.
Study of the Effect of pH and Supersaturation on the Kinetics and Rate of Solid Layer Formation at External Sides of Thermal Heat Transfer Tubes
IJTEE, volume-09 , Issue 2 (2015), PP 61 - 66
Published: 07 Apr 2015
by Waid S. Omar from Chemical Engineering Department, College of Engineering, King Faisal University, Al-Hofuf, Al-Ahsaa 31982, Saudi Arabia
Abstract: The formation of scale layers at the external sides of heated tubes at situations comparable with a Multi Effect Distiller (MED) desalination processes is experimentally studied. The growth of scale layer was measured at different temperatures, pH levels and salinities. The measured scale deposition rate data were correlated to the calcium carbonate supersaturation according to a power low kinetics. It was found that the growth rate order (n) with respect to supersaturation is strongly temperature dependent. It decreases with increasing temperature. The calculated value of activation energy of scale layer growth is Ea = 33360 J/mol. The scale layer growth was found to be strongly dependent on pH. It increases in the basic medium. The salinity was found to be significant in determining the growth rate of scale layer. The scale layer composition is affected by temperature. It was found that calcium carbonate is dominant at high temperatures (80 °C). calcium sulfate deposited besides calcium carbonate at lower temperatures (60-70 °C). read more... read less...
Keywords: scale layer, outer tubes, MED, kinetics, growth, pH, Temperature, activation energy, tubes.
IJTEE, volume-09 , Issue 2 (2015), PP 53 - 60
Published: 07 Apr 2015
by Md S. Opu from Oorja Fuel Cells, Fremont, California, USA, 949
Abstract: In this fundamental research investigation, the simple fundamental experimental design with two platinum wire as anode/cathode electrode and KOH solution as electrolyte were used throughout the experiments. The effect of electrolyte volume and concentration, electrode location and submerged length into the electrolyte, distance between two electrode and operating temperature on efficiency of water electrolysis was investigated. The results showed that the performance of alkaline water electrolysis is significantly affected by distance between electrode, electrolyte concentration and operating temperature. Higher rate of hydrogen production can be possible at smaller gap between electrodes with higher concentration of electrolyte operating at higher temperature. read more... read less...
Keywords: electrolyte, anode/cathode electrode, electrode location
Computational Analysis of Performance and Emissions of a Compression Ignition Engine under various Air Induction Methods
IJTEE, volume-09 , Issue 1 (2015), PP 47 - 52
Published: 25 Dec 2015
by Afaaq Ahmad Mir, M. Marouf Wanib from Research Scholar, NIT Srinagar, India,190006 Faculty of Engineering, NIT Srinagar, India,190006
Abstract: A computational study on performance and exhaust emissions from a 4-stroke DI CI engine using different air induction methods was carried out. Using AVL Boost IC engine simulation software a model was developed with a Naturally Aspirated (NA) air induction mode, the second model was developed by incorporating a turbocharger (TC) and again a third model was developed by the introduction of a turbocharger along with an intercooler (TCI). The individual effects of all the three air induction methods on the performance and emission of engine were studied and compared. The power output for the engine with TCI was observed to be 7.8% more than that of an engine with TC, where as it was even greater i-e 20% more when compared with NA engine. Similar Improved results for torque were also observed in case of an engine with TCI. It was also observed that emissions were higher with TCI followed with TC and NA. read more... read less...
Keywords: Air Induction, Turbo-charging, Inter-cooling, performance, Emissions
Application of Software for the Prediction of Heat Loss in Outdoor Condition during Physical Activity in Nigeria
IJTEE, volume-09 , Issue 1 (2015), PP 41 - 46
Published: 23 Dec 2015
by A. I. Musa, S.O. Ismaila, M.A. Waheed and T.M.A. Olayanju from Mechanical Engineering Department, Moshood Abiola Polytechnic, P.M.B. 2210, Abeokuta, Nigeria 110001 Mechanical Engineering Department, Federal University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria 110001 Agricultural Engineering Department, Federal University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria 110001
Abstract: The human body works to convert energy to provide desired thermal comfort level. This study developed a friendly-user software that is capable of determine and predict correctly the heat loss of a human being working in an outdoor environment. This task was with the use of mathematical model based on the conceptual heat balance equation of the human-environment interaction. There is lacks of computational simulation with user-friendly interfaces to simulating human body physiological responses in outdoor environment reference to the existing outdoor physical and physiological processes mathematical model. This study developed a simulation processes based on the mathematical model reported to determine the heat value, physical sweat rate production and predict the stored energy of human being working in an outdoor environment. This simulation presented was based on the 2nd law of thermodynamics. read more... read less...
Keywords: Outdoor, Human, Software, Energy, Environment, Model, Heat balance.
Feasibility of Using Volcanic Tuff Stone in Ground Heat Exchange for Cooling and Heating Systems in Buildings
IJTEE, volume-09 , Issue 1 (2015), PP 33 - 39
Published: 23 Dec 2015
by Sameh Sqoor, Mohmd Sarireh, Ali Alahmer , Wafa Tarawneh from Department of Mechanical Engineering, Tafila Technical University, P. O. Box 179, 66110 Tafila, Jordan Department of Civil Engineering, Tafila Technical University, P. O. Box 179, 66110 Tafila, Jordan
Abstract: Energy is a crucial sector in Jordan. In the world, Jordan is considered as the highest dependency on foreign energy sources, with 96% of the country's energy imported from oil and natural gas from neighboring countries. Numerically, it consumes 13% from the gross national product (GNP) costing 2.6 billion JD. The need is appearing to use new renewable resources specifically in air conditioning processes to reduce the bill of energy paid annually, in addition to the improve of practices and policies in energy sector. The current research focuses on the use of the ground heat exchange (GHE) model for cooling and heating system to improve the efficiency of the heating, ventilating, and air conditioning (HVAC) units in households and apartments using volcanic tuff stone. A GHE model was constructed by making a hole of 2 m X 1.5 m with a depth of 1.5 m, the volcanic tuff stone is placed enabling heat transfer through volume and voids of stone. The cooled air is extracted by a fan located at the exit (duct 20 X 20 cm) with electric capacity is 60 watts. The temperatures and relative humidity for air inlet and outlet were continuously measured during the period of testing. The results showed that the feasibility of using GHE model as a main part of heating/cooling system. The average temperature difference between the air inlet and exit of GHE model are or cooling and heating system respectively. Also, the relative humidity of air improves reasonably and increases in most cases. read more... read less...
Keywords: Ground heat exchange, energy, HVAC, volcanic tuff, cooling, heating.
Performance Analysis of an Irreversible Regenerative Brayton Cycle Based on Ecological Optimization Criterion
IJTEE, volume-09 , Issue 1 (2015), PP 25 - 32
Published: 23 Dec 2015
by Rajesh Kumara, S. C. Kaushik and Raj Kumar from Department of Mechanical and Automation Engineering, Amity University Haryana, Gurgaon-122413, India b Centre for Energy Studies, Indian Institute of Technology, Delhi, New Delhi-110016, India c Department of Mechanical Engineering, YMCA University of Science & Technology, Faridabad-121006, India
Abstract: An ecological optimization along with a detailed parametric analysis of an irreversible regenerative Brayton cycle with finite heat capacity of external reservoirs have been carried out. The external irreversibilities due to finite temperature difference and internal irreversibilities due to fluid friction losses in compressor / turbine, regenerative heat loss, pressure loss are included in the analysis. Ecological function is thermodynamically optimized which is defined as the power output minus the product of environment temperature and entropy generation rate. A detailed analysis shows that the ecological function and corresponding power output / thermal efficiency can be maximized with judicious selection of parameters such as efficiency of turbine and compressor, effectiveness of various heat exchangers, heat source inlet temperature, pressure drop recovery coefficients and heat capacitance rate of the working fluid. It is found that the regenerative effectiveness is more prominent for maximum ecological function and corresponding thermal efficiency while cold side effectiveness is dominant factor for corresponding power output. It is also found that the effect of turbine efficiency (ηt) is more than the compressor efficiency (ηc) on the thermodynamic performance of an irreversible regenerative Brayton heat engine cycle. The model analyzed in this paper gives lower values of various performance parameters as expected and replicates the results of an irreversible regenerative Brayton cycle model discussed in the literature at pressure recovery coefficients of α1=α2=1. read more... read less...
Keywords: Ecological Criterion, Irreversible Brayton cycle, Regenerator, Power, Efficiency
IJTEE, volume-09 , Issue 1 (2015), PP 17 - 24
Published: 23 Dec 2015
by Sunil J. Kulkarni, Jayant P. Kaware from Department of Chemical Engineering, Datta Meghe College of Engineering, Airoli, Navi Mumbai, India, Bhonsala College of Engineering and Research, Akola, Maharashtra, India
Abstract: In the current research, removal of cadmium from the effluent by using rice husk adsorbent is studied in packed bed with respect to various parameters like initial concentration, adsorbent dose, bed height and pH. Also the solute uptake data was analyzed for first and second order kinetic equations by varying these parameters. The effect of these parameters on kinetics of solute uptake is reported. It was observed that with increase in initial concentration from 10 mg/l to 50 mg/l, the exhaustion time decreased from 830 mg/l to 570 mg/l and break point time decreased from 330 minutes to 120 minutes. Also with increase in flow rate, exhaust time and break through time decreased significantly. The alkaline conditions favoured the adsorption with optimum pH of 6.The exhaustion and break through delayed with increasing bed height. The kinetics of the cadmium removal was affected by initial concentration and flow rate. At low initial concentration, it indicated second order kinetics. There was increasing shift from second to first order with increase in initial concentration. With increase in bed height from 30 to 40 cm there was shift from second to first order but with further increase in bed height, again shift towards second order kinetics was observed. The optimum bed height, initial concentration, flow rate and pH values were 50 cm,30 mg/l, 60 ml/min and 6 respectively. The adsorption efficiency was estimated to be 69 percent for optimum values of pH, initial concentration, bed height and flow rate. read more... read less...
Keywords: adsorbent, break through point, concentration, kinetics.
IJTEE, volume-09 , Issue 1 (2015), PP 7 - 16
Published: 23 Dec 2015
by S.M. Situmbeko, F.L. Inambao from University of KwaZulu-Natal, Durban, South Africa
Abstract: The paper presents work done on the development of a heat exchanger model suitable for incorporation into a low temperature solar thermal power cycle. In particular it presents the mathematical model comprising heat transfer, mass transfer, and convective heat transfer coefficients, and velocity and pressure drop correlations for single and two phase flows. The preliminary evaporator model is based on a counter flow double pipe configuration; the flow boiling process incorporates both convective and nucleate boiling. The shell side heat transfer fluid consists of ethylene glycol at 50 % concentration; the tube side fluid flow is modelled on four candidate working fluids pre-selected from previous stages of the research study. The evaporator model is implemented on the engineering equation solver platform; following on the computer simulation results a further proposal is made for conversion of the model design into a feasible shell-and-tube heat exchanger. The outputs of the model study are in the form of the rate of heat exchange, size and type of the heat exchanger, whilst ensuring that the pressure drops and fluid velocities are within acceptable limits. read more... read less...
Keywords: low temperature solar thermal, convective and nucleate boiling, engineering equation solver.
IJTEE, volume-09 , Issue 1 (2015), PP 1 - 6
Published: 23 Dec 2015
by Merlin Simo Tagne from Douala Higher Institute of Technology, Douala, Cameroon, PO Box 1623
Abstract: In the present paper, a numerical modeling of solar dryer is doing. This solar dryer operates in the natural convection condition and his construction is not difficult because, local materials are used and it is not necessary to follow a particular formation. We have obtained a numerical solution which explains experimental solution. Application is doing on ebony wood that is a wood most difficult to dry and most utilized for the sculpture. With 30mm of thickness, the sample passed 25 days to reduce his water content to 15%, initial water content was equal to 27%, and the drying period is the month of March from the town of Yaoundé, political capital of Cameroon. This modeling proposed is a modest contribution to explain the solar drying of tropical woods at the laboratory scale. read more... read less...
Keywords: Tropical woods, solar drying, modeling, numerical simulation, experiment, diospyros crassiflora.