Showing papers in "Journal of Power and Energy Engineering in 2013"

Fault Ride-Through Study of Wind Turbines

Abstract: The installation of wind energy has increased rapidly around the world. The grid codes about the wind energy require wind turbine (WT) has the ability of fault (or low voltage) ride-through (FRT). To study the FRT operation of the wind farms, three methods were discussed. First, the rotor short current of doubly-fed induction generator (DFIG) was limited by introducing a rotor side protection circuit. Second, the voltage of DC bus was limited by a DC energy absorb circuit. Third, STATCOM was used to increase the low level voltages of the wind farm. Simulation under MATLAB was studied and the corresponding results were given and discussed. The methods proposed in this paper can limit the rotor short current and the DC voltage of the DFIG WT to some degree, but the voltage support to the power system during the fault largely depend on the installation place of STATCOM.

Performance Characteristics of n-Butanol-Diesel Fuel Blend Fired in a Turbo-Charged Compression Ignition Engine

Abstract: In this study, n-butanol-diesel blends were burned in a turbo-charged, direct injection diesel engine where the brake thermal efficiency, (BTE) or brake specific fuel consumption, (BSFC) was compared with that of ethanol-diesel or methanol-diesel blends in another study by other authors. The test blends used were B5, B10 and B20 (where B5 is 5% n-butanol by volume and 95% diesel fuel-DF). In this study, the BTE was higher and the BSFC improved more than in the other study. Because of improved BTE with increasing brake mean effective pressure, BMEP, the BSFC reduced, however the increased shared volume of n-butanol in DF increased BSFC. Adding n-butanol in DF slightly derated the torque, brake power output with increasing speed, and caused a fall in exhaust gas temperatures, (EGT) which improves the volumetric efficiency and reduces compression work. Therefore, a small-shared volume of n-butanol in DF fired in a turbo-charged diesel engine performs better in terms of BTE and BSFC than that of ethanol or methanol blending in DF.

Estimation of Global Solar Radiation for Four Selected Sites in Nepal Using Sunshine Hours, Temperature and Relative Humidity

Abstract: Rational and accurate solar energy databases, essential for designing, sizing and performing the solar energy systems in any part of the world, are not easily accessible in different localities of Nepal. In this study, daily global solar radiation, sunshine hours and meteorological data for Biratnagar, Kathmandu, Pokhara and Jumla have been used to derive the regression constants. The linear regression technique has been used to develop a model for Biratnagar, Kathmandu, Pokhara and Jumla. The model has calculated the global solar radiation for these locations. The values of global solar radiation estimated by the model are found to be in close agreement with measured values of respective sites. The estimated values were compared with Angstrom-Prescott model and examined using the root mean square error (RMSE), mean bias error (MBE), mean percentage error (MPE), coefficient of regression (R), coefficient of determinant (R 2 ) and correlation coefficient (CC) statistical techniques. Thus, the resultant correlations and linear regression relations may be then used for the locations of similar meteorological/geographical characteristics and also can be used to estimate the missing data of solar radiation for the respective site.

Performance Investigation of Membrane Electrode Assemblies for High Temperature Proton Exchange Membrane Fuel Cell

Abstract: Different types of ABPBI (poly(2,5-benzimidazole)) membranes and polymer binders were evaluated to investigate the performance of MEAs for high temperature proton exchange membrane fuel cell (HT-PEMFC). The properties of the prepared MEAs were evaluated and analyzed by polarization curve, electrochemistry impedance spectroscopy (EIS), cyclic voltammetry (CV) and durability test. The results showed that MEA with modified ABPBI membrane (AM) has satisfactory performance and durability for fuel cell application. Compare to conventional PBI or Nafion binders, polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF) are more attractive as binders in the catalyst layer (CL) of gas diffusion electrode (GDE) for HT-PEMFC.

Retrofit of the Heat Recovery System of a Petroleum Refinery Using Pinch Analysis

Abstract: Energy efficiency has become an important feature in the design of process plants with the rising cost of energy and the more stringent environmental regulations being implemented worldwide. In South Africa, as elsewhere, most process plants built during the era of cheap energy place little emphasis on the need for energy recovery due to the abundance of cheap utilities sources such as coal. In most of these plants, there exist significant potential for substantial process heat recovery by conceptual design of the heat recovery system. By maximizing heat recovery from the processes, there will be a reduction in the process utilities requirement and the associated environmental effects. Pinch analysis has been demonstrated to be a simple but very effective tool for heat integration and optimization of chemical plants. This study uses the pinch principle to retrofit the heat exchanger networks (HEN) of the crude distillation unit of an integrated petroleum refinery to evolve a HEN that features optimum energy recovery. The network was further relaxed by trading off energy cost with capital cost to obtain an optimal HEN topology not too different from the existing network. The simulation works were implemented in AspenPlus v8.0 environment. Analysis revealed that 34 per cent saving on energy usage per annum is realizable. This significant saving in energy also results in diminished gaseous pollutants associated with energy usage.

Demonstration of Pilot Scale Large Aperture Parabolic Trough Organic Rankine Cycle Solar Thermal Power Plant in Louisiana

Abstract: During the calendar year of 2012 the University of Louisiana at Lafayette in conjunction with CLECO Power LLC (CLECO) has constructed and commissioned a pilot scale parabolic trough solar thermal power plant for the first time in Louisiana. The large aperture trough (LAT) solar collectors were provided by Gossamer Space Frames and are coupled with an organic Rankine cycle (ORC) power block provided by ElectraTherm, Inc. for study of the feasibility of cost-effective commercial scale solar thermal power production in Louisiana. Supported by CLECO and providing power to the existing CLECO grid, the implementation of state-of-the-industry collector frames, mirrors, trackers, and ORC power block is studied under various local weather conditions which present varied operating regimes from existing solar thermal installations. The solar collectors provide a design output of 650 kWth and preliminary actual performance data from the system level is presented. The optimal size, configuration and location for such a plant in the given solar resource region are being studied in conjunction with CLECO’s search for optimal renewable energy solutions for the region. The pilot scale size of the facility and implementation of the simpler ORC allow remote operation of the facility and flexibility in operating parameters for optimization studies. The construction of the facility was supported by the Louisiana Department of Natural Resources, the U.S. Department of Energy, and CLECO. The continued operation of the plant is supported by CLECO Power LLC and the University of Louisiana at Lafayette.

The Characteristics of the Evaporator/Evaporator for Direct Expansion Solar Assisted Heat Pump System

Abstract: Direct expansion solar assisted heat pump (DX-SAHP) technology is developed by combining solar energy heat utilization with heat pump energy saving technology. The experimental researches of the DX-SAHP hot water system are conducted in this paper, and overall performance of DX-SAHP is analyzed with three different structures of collectors/evaporators, namely a bare-plate collector, a glass-plate collector and double collectors/evaporators (a bare-plate collector and a glass-plate collector). The influence factors and overall performance are studied, which show that the overall performance of the system is mainly influenced by solar irradiation intensity and the collector area. Comparing with glass-plate collector in similar conditions, bare-plate collector system COP is higher. While increasing collector area is conducive to improve the system COP, but will reduce the collector efficiency and increase the workload of the compressor by comparing the bare-plate collector with double-plate collectors.

Circuit Model of 100 Ah Lithium Polymer Battery Cell

Abstract: This paper presents a circuit model for a 100 Ah Lithium Polymer Battery that takes into account the effect of temperature and discharge rates. This is done by studying the behavior of two advanced 100 Ah Lithium Polymer Battery cells under different load condition and at different temperatures, to extract the RC parameters needed to develop the equivalent circuit model. This paper presents a methodology to identify the several parameters of the model. The parameters of the circuit model depend on both, battery cell temperature and discharging current rate. The model is validated by comparing simulation results with experimental data collected through battery cell tests. The simulation results of the battery cell model are obtained using MATLAB, and the experimental data are collected through the battery test system at battery evaluation lab at University of Massachusetts Lowell. This model is useful for optimization of the battery management system which is needed to run a battery bank safely in an electric car.

Building Sustainable Score (BSS)—A Hybrid Process Approach for Sustainable Building Assessment in China

Abstract: Sustainable building in China has gained attention both domestically and abroad. Despite the fast increase in sustainable assessment tools developed locally or adopted from overseas, there are still criticisms about the current situation of weak implementation and lack of comprehensive consideration. The lack of consideration of economic and social aspects or building performance on whole building life cycle all lead to departure from the true meaning of sustainable development. And lack of participation on the part of stakeholders makes it too theoretical to be carried out. This research aims to develop a model to address this problem. This research started with review of current sustainable assessment tools applied in China. As the assessment indicators have clear regional disparities, and almost no current tool considers all three pillars of environmental, economic and social in building life cycle. An industry survey was therefore designed for generation of indicators at different building stages, and personal interviews relevant to different occupation in building industry were conducted to complement the questionnaire survey. After that, the model Building Sustainable Score (BSS) was developed based on the stakeholders’ participation. Finally, the model is verified by a case study.

Developments of Multifunctional Additives for High Quality Lube Oil

Abstract: In most lubrication systems, the oil is mixed with air, in contact with air, in contact with metals and at high temperature. This is mean cause of premature lubricant, deterioration which can result in oxidation products, which are mainly acid. Hydrocarbon oxidation in the liquid phase proceeds by a radical chain reaction. In the present paper polyalkylphenol formaldehyde sulphonate and its ethoxylate were synthesized and evaluated as pour point depressant, viscosity improver and antioxidant. The efficiency of these additives depends on their chemical structure and degree of mixing (mole fraction). Values of surface tension of these additives were measured in oil phase and consequently CMC was determined for all additives and their mixtures. A novel method of inhibiting oxidation was proposed. The author suggests the mechanism of inhibiting oxidation according to surface activity of additive in oil phase. More confirmations for suggested mechanism were investigated by measuring the area occupied per molecule of additive at oil phase. The results indicate that the compatibility of sulphonate with ethoxylate group and forming stable micelle which acts as wax dispersant and improver viscosity.

CdHgTe Quantum Dots Sensitized Solar Cell with Using of Titanium Dioxide Nanotubes

Abstract: The sensitization of TiO2 nanotubes with CdHgTe quantum dots (QDs) was applied by using the direct dispersion technique. The CdHgTe-QDs were fabricated with different Hg% ratio in organic medium for controlling their particle size. While TiO2 nanotubes (NTs) were fabricated by anodization technique. The QDs and NTs were characterized using SEM, TEM and UV-VIS spectrophotometer. In this work, the photovoltaic parameters of the quantum dots sensitized solar cell (QDSSC) depend mainly on the Hg% ratio in the QDs. The most efficient QDSSC was obtained at 25% of Hg ratio with Jsc of 4 mA/cm2, Voc of 0.63 V, FF of 0.32 and efficiency of 0.81%.

Addressing the challenge of interpreting microclimatic weather data collected from urban sites

Abstract: This paper presents some installation and data analysis issues from an ongoing urban air temperature and humidity measurement campaign in Hangzhou and Ningbo, China. The location of the measurement sites, the positioning of the sensors and the harsh conditions in an urban environment can result in missing values and observations that are unrepresentative of the local urban microclimate. Missing data and erroneous values in micro-scale weather time series can produce bias in the data analysis, false correlations and wrong conclusions when deriving the specific local weather patterns. A methodology is presented for the identification of values that could be false and for determining whether these are “noise”. Seven statistical methods were evaluated in their performance for replacing missing and erroneous values in urban weather time series. The two methods that proposed replacement with the mean values from sensors in locations with a Sky View Factor similar to that of the target sensor and the sensors closest to the target’s location performed well for all Day-Night and Cold-Warm days scenarios. However, during night time in warm weather the replacement with the mean values for air temperature of the nearest locations outperformed all other methods. The results give some initial evidence of the distinctive urban microclimate development in time and space under different regional weather forcings.

Industrial Feasiblity of Direct Methane Conversion to Hydrocarbons over Fe-Based Fischer Tropsch Catalyst

Abstract: Recently, as a direct consequence of the dwindling world oil reserves and the growing awareness of the environmental problems associated with the use of coal as energy source, there is growing interest in cheaper, abundant and cleaner burning methane. The Gas-to-Liquid technology offers perhaps the most attractive routes for the exploitation of the world huge and growing natural gas resources. Using this process the erstwhile stranded gas is converted to premium grade liquid fuels and chemicals that are easily transported. However, a widespread application of the GTL process is being hampered by economical and technical challenges. The high cost of synthesis gas, for instance, weighs heavily on the economics and competitiveness of the process limiting its wider application. This work presented a modified Gas-to-Liquid process that eliminates the costly synthesis gas production step. The proposed process utilized an alternative pathway for methane activation via the production of chloromethane derivatives which are then converted to hydrocarbons. It established that hydrocarbons mainly olefins can be economically produced from di- and tri-chloro- methanes over a typical iron-based Fischer Tropsch catalysts in a moving bed reactor at industrially relevant conditions. Some of the attractions of the proposed process include a) the elimination of the costly air separation plant requirement b) high process selectivity and c) significant reduction of carbon dioxide emissions thereby saving on feedstock loss and the costly CO2 removal and isolation processes.

The Effects of Future Climate Change on Energy Consumption in Residential Buildings in China

Abstract: China is currently going through a phase of rapid mass urbanisation, and it is important to investigate how the growing built environment will cope with climate change, to see how the energy consumption of buildings in China will be affected. This is especially important for the fast-growing cities in the north, and around the east and south coasts. This paper aims to study the effects of future climate change on the energy consumption of buildings in the three main climate regions of China, namely the “Cold” region in the north, which includes Beijing; the “Hot Summer Cold Winter” region in the east, which includes cities such as Shanghai and Ningbo; and the “Hot Summer Mild Winter” region in the south, which includes Guangzhou. Using data from the climate model, HadCM3, Test Reference Years are generated for the 2020s, 2050s and 2080s, for various IPCC future scenarios. These are then used to access the energy performance of typical existing buildings, and also the effects of retrofitting them to the standard of the current building codes. It was found that although there are reductions in energy consumption for heating and cooling with retrofitting existing residential buildings to the current standard, the actual effects are very small compared with the extra energy consumption that comes as a result of future climate change. This is especially true for Guangzhou, which currently have very little heating load, so there is little benefit of the reduction in heating demand from climate change. The effects of retrofitting in Beijing are also limited, and only in Ningbo was the effect of retrofitting able to nullify the effects of climate change up to 2020s. More improvements in building standards in all three regions are required to significantly reduce the effects of future climate change, especially to beyond 2020s.

Efficiency of Amphoteric Surfactants as Flow Improvers and Pour Point Depressants

Abstract: Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorption behavior of these surfactants at oil/air interface was investigated by measuring the surface tension and interfacial tension as function of concentration. Surface properties, in particular the critical micelle concentration (CMC), the maximum surface excess (ΓCMC) and the minimum surface area (AMIN) were measured. It is found that the surface and thermodynamic properties of the prepared surfactants depend on their hydrocarbon chain length. Also it is found that there is a good relation between surface properties of the additive and their efficiency in depressing the pour point. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. As the results the surface and thermodynamic parameters confirm the suggested mechanism and the decreasing of pour point. This is resulted in a multilayer, more isotropic wax crystal, and thus only a fixed amount of wax separates at any given temperatures. The results were discussed in terms of adsorption isotherm.

Break-Even Analysis on the Charging and Battery-Swapped Station of Electric Vehicles

Abstract: The construction of electric vehicle charging station plays an important role in the development of electric vehicles and the promotion of the renewable resource. In the paper, a model to analyze the economic benefit of the charging station is presented, which is based on the break-even theory. Then the threshold price is calculated based on the model according to the construction plans of charging facilities in one district. Finally, the strategy for the development of charging faculties is proposed to improve the health growth of electric automotive industry.

Optimum Inclination Angles of Booster Mirrors and Solar Radiation Availability on the Horizontal and Inclined Box Type Solar Cookers

Abstract: Mathematical relations are developed to compute optimum inclination angle of booster mirror for horizontally placed cooker (λ) and for optimally inclined cooker (ψ) during all months (selected day) of the year at 30°N latitude for maximizing the reflected component of solar intensity onto the absorber plate of the cooker. A solar radiation model is also developed and used to compute the ratio of various solar intensities on horizontal, inclined and normal surface of the absorber plate for all months at 30°N latitude. These ratios give a clear indication of greater solar radiation availability on the optimally inclined cooker as compared to the horizontally placed cooker for faster cooking especially during winter months when solar radiation capture is small. Experimental validations have also been performed to access the accuracy of the developed relations and model.

Cold-State Investigation on a Flame Holder

Abstract: Slitty bluff body is widely used as a high-performance flame holder in power industry. To understand the flame stability mechanism, the evolution of the near wake over a slitty bluff body in cold state was numerically investigated using the renormalization group (RNG) k-e model at Reynolds number of 470,000. The coherent structure of the near wake was identified by the vortex shedding simulation. To explain the vortex shedding, a mechanism that single vortex of large size suddenly immerses two shear layers was proposed. To quantitatively compare the near wakes at different gap ratio, a vortex shedding character dimension was first proposed. This character dimension has positive correlation with flame stability. Particle-image velocimetry (PIV) measurements in a close wind tunnel were also carried out to confirm the observation from the numerical study. The evidence shows that the numerical results are of good agreement with the cold-state experiments.

Technical and Economical Merits of Power Systems Interconnection

Abstract: This work aims at exploring the effects of the interconnection between isolated electric power systems upon some important aspects such as enhancing reliability levels along with reducing installation and operation costs. To discern the advantages associated with this study, the developed methodology has been applied to three existing power systems in the northern region of the Kingdom of Saudi Arabia presently within the concession domain of the Saudi Electric Company (SEC). These systems have been established to meet the present loads and to withstand future electrical demands for a period of time before additional generation and transmission reinforcements are needed. In this work, reliability measures have been utilized to determine the period that these systems can fulfill the present and future loads without affecting the reliability levels and the threshold that an additional capacity should be added to maintain those required reliability levels. In application to the reliability criteria, technical, operational and economic advantages can be realized, i.e., higher reliability levels and lower installation and operation costs after the proposed interconnection between these selected isolated power systems take place.

New Multilevel Mixed Topology Development to Improve Inverter Robustness for Domestic Photovoltaic Installations

Abstract: Multilevel inverters are well used in grid connected domestic photovoltaic applications because of their ability to generate a very good quality of waveforms, reducing switching frequency, and their low voltage stress across the power devices. However, this kind of inverter has to be modified to both limit common-mode currents and improve the robustness of the system. This paper presents a new mixed 5-level inverter that meets these challenges. The operating principle of the converter is proposed. Several experimental measurements are described to validate this new concept. The output voltage and current and the THD of the output voltage are particularly discussed.

Early Failure Detection in Power Transformers

Abstract: This paper presents equipment for early detection of failures in the insulation of power transformers, checking existing partial discharges inside. The equipment involves hardware, control and signal acquisition software, and signal analysis software. This equipment has a set of algorithms that were made with intelligent extraction techniques and interpretation of data. The degradation diagnosis of the equipment insulation is based on digital signal processing algorithms for extraction of features and also in artificial intelligence algorithms that allies a mining involving all the data linked to the equipment throughout its operating life can make an assessment of the operating conditions of the equipment and suggest interventions and provide an estimated time so that they have to be made.

The Carbonation Behaviors of Limestone Particle in Oxygen-Fuel Circulating Fluidized Bed O 2 /CO 2 Flue Gas

Abstract: Limestone powder is still applied as SO2 sorbent in emerging oxygen-fuel circulating fluidized bed boiler, but its carbonation in O2/CO2 flue gas is an unclear problem. For a better understanding of carbonation behaviors, the tube furnace heating system was built for simulating circulating fluidized bed boiler flue gas by regulating the supply of O, CO2, N2, SO2 and H2O, and Carbonation reaction was tested. Thermal gravimetric analysis and scanning electron microscopy were used. It was found that carbonation is closely related to temperature, CO2 concentration, impurities, water vapor, and cycle times; high temperature can promote carbonation process; high concentration of CO2 can inhibit the chemical reaction stage speed of carbonation process, but it has little effect on the final conversion rate; water vapor can increase the final conversion rate of carbonation; the cycle times will reduce the activity of carbonation. The presence of carbonation turns the traditional boiler flue gas indirect desulfurization model into indirect desulfurization mechanism which does not have a negative impact on SO2 removal efficiency.

Development Status, Problems and Countermeasures of Large- and Intermediate-Scale Biogas Projects in Beijing’s Mountainous Counties

Abstract: Developing large- and intermediate-scale biogas project is an important gripper ofBeijingrural energy construction and “Green Beijing” construction. The existing projects have made obvious energy and environment benefits, but the overall effects have not been fully exerted. There is still a large gap betweenBeijing’s ecological civilization goal and the operation effect. This paper takes biogas projects ofBeijingseven mountainous counties as examples, the development status, ecological environment construction and existing problems of operating are explained respectively. Finally, some countermeasures and suggestions are proposed for promoting the sustainable development of biogas project inBeijing, such as strengthening technical innovation and setting standards, innovating development patterns and planning reasonable layout, improve the maintenance mechanism and intensify policy support.

Estimation of the Temperature in the Weld Penetration Channel in Electron Beam Welding

Abstract: In this paper, the method of experimental estimation of the temperature in a penetration channel in electron beam welding is described on the basis of chemical elements concentration in the vapors above welding zone. The temperature of a vapor-gas phase in the penetration channel is determined when equating calculated and experimental concentrations of the elements.

Analysis of Dynamic Cross Response between Spindles in a Dual Spindle Type Multi-Functional Turning Machine

Abstract: In order to meet increasing demand for higher productivity and flexibility, recently many kinds of multi-functional machine tools, which are capable of multiple machining functions or different kinds of machining processes on one machine, have been developed and widely used in manufacturing industries. In this study, a multi-functional turning lathe, which has two spindles and two turrets so that multiple turning operations and various machining processes could be performed simultaneously, has been developed. Furthermore, the equations of correlation between whole responses and cross responses of the two spindles have been derived to examine to what extent the two spindles affect each other’s vibrations.

Diesel Engine Emissions and Performance Characteristics under Cape Chestnut Biofuel

Abstract: Cape Chestnut oil was processed to biodiesel through transesterification. Cape Chestnut kennels are reported to have oil content of 60% - 63% [1]. Properties of biodiesel were determined and compared with those of diesel and engine tests done at a constant speed of 1500 RPM on the biodiesel blends to evaluate their performance and emissions characteristics. Performance evaluation was in terms of Brake Specific Fuel Consumption (BSFC), Brake Horse Power (BHP) and Brake Thermal Efficiency (ETE). The engine was initially run on diesel to establish the reference characteristics before running on biodiesel blends. The biodiesel was blended with diesel volumetrically to 80% (B80), 50% (B50), 20% (B20) and 5% (B5) the percentage being the volume of biodiesel in the blended fuel. Diesel fuel had the lowest BSFC followed by B5 whose BSFC was 7.3% higher than that of diesel. BTE for B100 was lower than that of diesel by 20.3% while that of B5 was 7.6% lower. Concentration of SO2 in B100 was 92.7% lower than that of diesel fuel while that of B20 was 24.7% lower. NO and NO2 concentrations for B100 were around 15% higher than that of diesel. Particulate matter of less than 10 μm diameter (PM10) for diesel was found to be 72% of the total collected from all the test fuels as compared to that of biodiesel blends at 28%. The study concluded that Cape Chestnut biodiesel blends containing up to 20% biodiesel can be used in an unmodified diesel engine since their performance and emission characteristics were very similar to that of diesel but with reduced toxic gas emissions therefore friendly to the environment.

Evaluation of Geometric Quality of Weld Beads in the Joining of Carbon Steel Pipelines with Single Pass

Abstract: This work presents the uncertainty evaluation associated with the measurement of linear parameters that define the weld geometry, specifically the width, using a profile projector, in order to meet the current technical standards. The following steps were proposed and implemented: identification of linear parameters that define the weld geometry; identification and study of variables that affect the measurement of these parameters; the adoption of the mathematical model to estimate the uncertainty; planning and execution of experiments for data collection, calculation of uncertainty and, finally, analysis and discussion of the results. Through the results analysis it was concluded that the weld in overhead position produces the lowest front bead width values and the vertical weld produces the largest width values. The expanded uncertainty values were between 0.016 mm and 0.075 mm for all measurements, and the overhead position showed, on average, the highest values.

An Experiment on Power Properties in a Small-Scaled Wind Turbine Generator

Abstract: This study configures a simple wind tunnel using a blower for generating wind energy, which is equivalent to natural wind, and a test system that measures properties of power. Also, the mechanical and electrical power in a small-scaled wind turbine are empirically measured to analyze the relationship between the mechanical and electrical power.

Test and Evaluation of Stiffness of a Pin Turning Device for Large Marine Engine Crankshafts

Abstract: In order to prevent unwanted excited vibrations and to secure better machining precision in large size heavy duty machine tools dynamic stiffness is one of the most desirable and critical properties. In the past decades, many researches on machine tool stiffness test and evaluation methodology have been made. However any methodology for a Pin Turning Device (PTD), which is a special kind of turning lathe for machining big size crankshaft pins, is rarely found among them. This study proposes a test and evaluation process of stiffness of a PTD by measuring frequency response function at the tool center point (TCP). For conformance proving for the proposed methodology, stiffness of a PTD obtained by the proposed method with impact hammer test (IHT) has been compared with that determined by FEM.

Study of Seals on Long Stroke and Reciprocating Motion Condition

Abstract: The equipment has a high and strict requirement of dynamic seals, especially working with Long stroke reciprocating motion under a sandy condition and with a great deal of gas. The seal form of power cylinder on the underground part of hydraulic power rodless type oil extraction equipment is studied. We design three seal structures, do the performance testing and the life testing with related equipment. It turned out that the seal form that combines gap seal with sand prevention techniques has high performance, longer life. The power cylinder works stably and reliably.