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Opposed-Piston Crankshaft System Dynamics Simulation and Durability Analysis in a Neotype Two-Stroke Diesel Engine
Chang Ming He,
Si Chuan Xu
Issue:
Volume 2, Issue 2, March 2017
Pages:
54-63
Received:
27 October 2016
Accepted:
8 December 2016
Published:
16 January 2017
Abstract: For the opposed-piston and opposed-cylinder (OPOC) diesel engine with higher power density, recently it has drawn even more attentions than ever in several developed countries, such USA and Germany, et al, which is regarded as a technical innovation to further reduce emission, and decrease fuel consumption, attributed to outstanding thermal efficiency and engine package downsizing. To explore the interrelation of this special crank system in concept design stage, the multi-body dynamics and durability of the piston-opposed crankshaft system was investigated. Firstly the optimized function model of the unique crankshaft system in an OP2S (Opposed-piston two stroke) engine was established. Then it was to figure out the influence of all structural design parameters on OPE crankshaft averaged output torque, respectively. The calculated results show that the initial crank angle difference between inner crank web and outer crank web was the most critical contributor to elevate the averaged torque output than other structural parameters. The parametric 3D model of crankshaft system was refreshed automatically based on the optimized variables. Finally an OPE crankshaft prototype was manufactured and bend fatigue experiment was carried out in a relevant laboratory to obtain the material S-N Curve. The HCF (High Cycle Fatigue) result was indicated that the minimum safety factor on crank journal fillets can reach relevant estimation criterion without crankshaft failure occurring for an engine speed sweep.
Abstract: For the opposed-piston and opposed-cylinder (OPOC) diesel engine with higher power density, recently it has drawn even more attentions than ever in several developed countries, such USA and Germany, et al, which is regarded as a technical innovation to further reduce emission, and decrease fuel consumption, attributed to outstanding thermal efficie...
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Adaptive Tuning of Sliding Mode-PID Control in Free Floating Space Manipulator by Sliding Cloud Theory
B. Kharabian,
H. Bolandi,
A. F. Ehyaei,
S. K. Mousavi Mashhadi,
S. M. Smailzadeh
Issue:
Volume 2, Issue 2, March 2017
Pages:
64-71
Received:
20 September 2016
Accepted:
27 December 2016
Published:
20 January 2017
Abstract: In this paper, a combinational control approach of sliding mode-PID is utilized in free floating space manipulator. Due to float base, nonlinearity of free floating space manipulator dynamics lead to having unstable behaviour and complicated dynamic model. To simplify the dynamic equation, dynamically equivalent manipulator is utilized which is a fixed base manipulator. In this approach, an unique map transfers dynamic parameters of free floating space manipulator to a fixed base manipulator. This transfer enlarges uncertainty bound of parameters. Hence, sliding mode-PID control as a combinational robust control approach is applied in the system. In this case, PID like sliding surface is proposed instead of conventional sliding surface. Adaptive tuning of sliding surface provides a Sliding Cloud that is a kind of dynamic sliding surface. In this way, inclination of system to stable behaviour increases and robustness of system, in the presence of uncertainties, is bolstered.
Abstract: In this paper, a combinational control approach of sliding mode-PID is utilized in free floating space manipulator. Due to float base, nonlinearity of free floating space manipulator dynamics lead to having unstable behaviour and complicated dynamic model. To simplify the dynamic equation, dynamically equivalent manipulator is utilized which is a f...
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Maintainability Evaluation of Steam and Gas Turbine Components in a Thermal Power Station
Christian Emeka Okafor,
Augustine Alexander Atikpakpa,
Ugochukwu Chuka Okonkwo,
Ekerikevwe Kennedy Irikefe
Issue:
Volume 2, Issue 2, March 2017
Pages:
72-80
Received:
10 November 2016
Accepted:
27 December 2016
Published:
20 January 2017
Abstract: Maintenance costs have risen steadily over recent years in proportion to total investment in thermal power stations, however lack of regular maintenance can result in serious equipment failure with catastrophic consequences. In general, the Nigerian power generation capability has nosedived to an abysmal level, particularly at the generation stations due to poor maintenance culture. This paper evaluated maintainability of steam and gas turbines components in a thermal power station. Data were obtained from a thermal power station in Nigeria; these raw data were extracted from the operation department, which represents records of plant generation capabilities as well as other inherent daily conditions that will enhance the success of this study. Various maintainability measures were used in analyzing the data, the study implemented log normal distribution considering that most turbines fails due to fatigue and other phenomenon that are caused by ageing or wear resulting in failure rates that increase with time. The estimated mean time to failure of turbine 2 reduced from 35744.5 hours to 33643.8 hours after the use of a condition based preventive maintenance policy. Mean Preventive Maintenance Time (MPMT) for Economizer Inlet non Return Valve and its effect on steam turbine 1 ranges from 77144hrs to 4296hrs for gas turbine 2. The station overall mean maintenance time showed that steam turbine 1 has a maximum hours (77144hrs), while its is minimum for gas turbine2 (4296 hrs). MPMT of sub-equipment is maximum up to 48717 hrs on Gear defect/Hood diaphragm for steam turbine 2; also maximum for the Economizer Inlet non Return Valve, while this was minimum about 48708 hrs for the water pump. For gas turbine 2 MPMT hours for seal leakages and air filters have a maximum value of about 4295.5 hrs, while it is very low on other equipment. The equipment maximum corrective maintenance time (MCMT) of various turbines is higher for steam turbine 2 (10.04 hrs), while minimum for gas turbine 2 (10.00 hrs). Conclusively, planned maintenance tasks can reduce the number of unplanned or emergency trips of these turbines.
Abstract: Maintenance costs have risen steadily over recent years in proportion to total investment in thermal power stations, however lack of regular maintenance can result in serious equipment failure with catastrophic consequences. In general, the Nigerian power generation capability has nosedived to an abysmal level, particularly at the generation statio...
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Influence of Core Compressibility, Flexibility and Transverse Shear Effects on the Response of Sandwich Structures
Koovapparambil Ramunny Pradeep,
Boggarappu Nageswara Rao,
Sivakumar Madras Srinivasan,
Krishnan Balasubramaniam,
Sirajudeen Ahamed
Issue:
Volume 2, Issue 2, March 2017
Pages:
81-91
Received:
15 October 2016
Accepted:
6 December 2016
Published:
21 January 2017
Abstract: This paper examines the adequacy of first order shear deformation theory (FSDT) based layered shell finite element by comparing with 2D and 3D models without imposing any constraint on the deformation behaviour of core. The effect of core compressibility and transverse flexibility in the behaviour of sandwich beams are studied. Plane and 3D models are able to capture the higher order shear stress variation across the thickness of core, whereas classical models and layered models results in constant shear stress across the thickness of the core. Results of the finite element models indicate the necessity of shear correction factor for rigid core considering shear strain energy criteria or average shear strain criteria, whereas for soft core, the shear correction factor is unity (=1).
Abstract: This paper examines the adequacy of first order shear deformation theory (FSDT) based layered shell finite element by comparing with 2D and 3D models without imposing any constraint on the deformation behaviour of core. The effect of core compressibility and transverse flexibility in the behaviour of sandwich beams are studied. Plane and 3D models ...
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Optimum Drilling Parameters of Coir Fiber-Reinforced Polyester Composites
Doddapineni Rajeev Kumar,
P. S. Sravan Kumar Varma,
Boggarapu Nageswara Rao
Issue:
Volume 2, Issue 2, March 2017
Pages:
92-97
Received:
15 October 2016
Accepted:
6 December 2016
Published:
21 January 2017
Abstract: This paper presents optimum drilling parameters of coir fiber reinforced polyester composites following the Taguchi design of experiment. A simple multi-objective optimization approach is suggested and presented an efficient prediction methodology to estimate thrust force, torque and tool wear for the identified optimum process parameters.
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A Comparative Study of Energy Consumption for Residential HVAC Systems Using EnergyPlus
Issue:
Volume 2, Issue 2, March 2017
Pages:
98-103
Received:
2 November 2016
Accepted:
5 January 2017
Published:
24 January 2017
Abstract: Energy conservation and sustainability have become an attractive field for research due to the growth in population and continuing search for better living standards. Heating, Ventilation, and Air Conditioning (HVAC) systems account for almost half of consumed energy in buildings and around 10 to 20% of total energy consumption in developed countries. In general, the trend of installing central HVAC systems increases in residential and commercial buildings. In this research, a study of energy consumption of HVAC systems in residential buildings has been conducted with the aim to compare those systems from an energy consumption point of view. The final goal of this research is to reduce energy requirements of residential buildings sector to save energy and reduce carbon emission. A medium size residential building in the city of Tripoli, Libya, was selected as a case study. EnergyPlus building simulation software along with OpenStudio software were used to model the house and HVAC systems. The results show that the virtual component “ideal air loads” used in EnergyPlus is very easy to use, however, its calculated energy consumption is overestimated compared to other models. Therefore, using that component can be misleading and may result in high monthly and annually energy consumption results. The results also show that in a residential building, unitary systems consume the least annual energy consumption compared to other models. It was concluded that variations in energy consumption of the considered HVAC systems decrease as the coefficient of performance (COP) increases and visa verse.
Abstract: Energy conservation and sustainability have become an attractive field for research due to the growth in population and continuing search for better living standards. Heating, Ventilation, and Air Conditioning (HVAC) systems account for almost half of consumed energy in buildings and around 10 to 20% of total energy consumption in developed countri...
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Determination of Monthly Unit Cost of Energy for Standalone Photovoltaic System in Owerri, Imo State
Umoren Mfonobong Anthony,
Mfonobong Charles Uko,
Ogungbemi Emmanuel Oluropo
Issue:
Volume 2, Issue 2, March 2017
Pages:
104-110
Received:
31 October 2016
Accepted:
4 January 2017
Published:
29 January 2017
Abstract: In this paper, simulation approach is used for determination of the monthly unit cost of energy generated from standalone PV (SAPV) power system in Imo State. The meteorological data used in the study are compiled from National Aeronautics and Space Administration (NASA) worldwide meteorological database. The meteorological data include 22-year monthly and annual averaged insolation incident on a horizontal surface (kwh/m2/day) and 22-year monthly averaged air temperature. A hypothetical electric load demand data of 5000 kWh per day is used for the simulation. The PVsyst industrial PV system planning software solution was selected to model and simulate the entire PV system. PVSyst uses life cycle cost analysis approach to determine the investment cost and unit cost of energy generated from SAPV system. According to the results, the average total energy supplied to the user (load) in a year is 1751 kWh. The economic analysis result shows that the total annual cost of energy is 246760 Naira per year at a unit cost of 141 Naira per kWh. Also, the highest unit cost of energy of 168.6 Naira/ kWh occurred in August whereas the lowest unit cost of energy of 132.7 Naira/ kWh occurred in October. The idea presented in this paper is useful for smart grid, dynamic energy pricing and energy cost management system.
Abstract: In this paper, simulation approach is used for determination of the monthly unit cost of energy generated from standalone PV (SAPV) power system in Imo State. The meteorological data used in the study are compiled from National Aeronautics and Space Administration (NASA) worldwide meteorological database. The meteorological data include 22-year mon...
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Influence of Abrasives in Roller Burnishing Process on Microhardness Using Factorial Design
Pavana Kumara,
G. K. Purohit
Issue:
Volume 2, Issue 2, March 2017
Pages:
111-116
Received:
20 October 2016
Accepted:
28 November 2016
Published:
16 February 2017
Abstract: Burnishing is essentially a cold-working process used to improve properties of the machined surfaces. In present work, an attempt is made to investigate the effect of fine silicon carbide abrasive particles (in the form of a paste) in between roller burnishing tool and cylindrical components of EN24 steel. The mathematical models were developed using 2 4 full factorial design of experiments (DoE) for micro hardness in terms of four variables namely burnishing force, burnishing speed, feed and a number of passes for dry burnishing case and ‘with-paste’ (where burnishing is done using paste) burnishing case. Analysis of variance (ANOVA) is carried out to check the adequacy of the derived models. The results showed that micro hardness of the untreated EN24 steel can be improved by 11% and 18% for dry burnishing case and ‘with-paste’ burnishing case respectively compared to turned components.
Abstract: Burnishing is essentially a cold-working process used to improve properties of the machined surfaces. In present work, an attempt is made to investigate the effect of fine silicon carbide abrasive particles (in the form of a paste) in between roller burnishing tool and cylindrical components of EN24 steel. The mathematical models were developed usi...
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