bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of an Equipment Reliability Program With Smart, Connected Power Plant Assets
Authors: Reid Michael , File Tony
Published: September 2017

The U.S. electric utility industry continues to undergo dramatic and accelerating transformation. Reliability and resiliency are a key focus. A number of important issues including cyber and physical security challenges, aging infrastructure, and low natural gas prices continue to be of concern. Significant advances in technology, and prolonged regulatory uncertainty are also contributing factors.

Electric utilities are now making substantial investment in renewable resources and other technologies needed for renewables integration. This means a reduction in investment in generation assets and an increase in the transmission and distribution grids. There is also increased investment in providing customers with solutions to lower their costs, reduce their carbon footprint and provide control over their energy management.

The transformation ultimately demands significant increases in power plant generation operating capabilities and higher levels of equipment reliability while reducing O&M and capital budgets. Achieving higher levels of equipment reliability, with such tightening budget and resource constraints, requires a very disciplined approach to maintenance and an optimized mix of the following maintenance practices:

• Preventative (time-based)

• Predictive (condition-based)

• Reactive (run-to-failure)

• Proactive (combination of 1, 2 and 3 + root cause failure analysis)

Preventive maintenance (PM) is planned maintenance actions taken to ensure equipment is capable of performing its required functions. PM tasks are generally time-based, depending on the availability of condition monitoring data through a predictive maintenance (PdM) program.

Traditionally, PdM is largely performed by maintenance technicians in the field with handheld devices. Resource constraints usually mean that often weeks or even months elapsed between readings on the same piece of equipment. This approach has limitations with data volume, velocity, variety, and veracity.

Significant recent advances in sensor and technology associated with the Industrial Internet of Things (IIoT) have enabled the transformation of critical power plant assets such as steam turbines, combustion turbines, generators, and large balance-of-plant equipment into smart, connected power plant assets. These enhanced assets, in conjunction with analysis and visualization software, provide a comprehensive on-line conditioning monitoring solution that enables both a reduction in time-based PM tasks and also automation of PdM tasks.

This paper describes an approach by Duke Energy to apply smart, connected power plant assets to greatly enhance its fossil generation equipment reliability program and processes. It will outline the value that is currently being realized and will also examine additional opportunities.
Prediction Model of Flow-Induced Noise in Large-Scale Centrifugal Pumps Based on BP Neural Network
Authors: Guo Chang , Gao Ming , Dong Peixin , Shi Yuetao , Sun Fengzhong
Published: September 2017

As one kind of serious environmental problems, flow-induced noise in centrifugal pumps pollutes the working circumstance and deteriorates the performance of pumps, meanwhile, it always changes drastically under various working conditions. Consequently, it is extremely significant to predict flow-induced noise of centrifugal pumps under various working conditions with a practical mathematical model. In this paper, a three-layer back propagation (BP) neural network model is established and the number of input, hidden and output layer node is set as 3, 6 and 1, respectively. To be specific, the flow rate, rotational speed and medium temperature are chosen as input layer, and the corresponding flow-induced noise evaluated by average of total sound pressure level (A_TSPL) as output layer. Furthermore, the tansig function is used to act as transfer function between the input layer and hidden layer, and the purelin function is used between hidden layer and output layer. The trainlm function based on Levenberg-Marquardt algorithm is selected as the training function. By using a large number of sample data, the training of the network model and prediction research are accomplished. The results indicate that good correlation is established among the sample data, and the predictive values show great consistence with simulation ones, of which the average relative error of A_TSPL in process of verification is 0.52%. The precision of the model can satisfy the requirement of relevant research and engineering application.
Experimental Investigation on Heat Transfer and Frictional Characteristics of Vertical Upward Rifled Tube in the Advanced Ultra Supercritical Steam Generator
Authors: Wang Siyang , Qu Mofeng , Jiang Huiqing , Zhao Yunjie , Yang Dong
Published: September 2017

This paper experimentally studied the heat transfer and frictional characteristics of a single rifled tube with vertical upward flow under the parametric range of pressures P = 10.5–32 MPa, mass fluxes G = 300–1300 kg·m−2·s−1, heat fluxes q = 275–845 kW·m−2. The results show that in the subcritical pressure region, dryout is the predominant mode of heat transfer deterioration. In the near critical pressure region, departure from nuclear boiling (DNB) occurs when the q/G value increases. In the supercritical pressure region, heat transfer and frictional characteristics will be strongly influenced by the sharp changes of the thermophysical properties of supercritical water when the value of mass flux is approximately lower than 1000 kg · m−2 · s−1 in this experiment. The mass flux and the pressure are two crucial factors to the variations of total pressure drop and frictional pressure drop. An empirical correlation is selected to estimate the frictional pressure drop. The results indicate that in the low mass flux circumstances, the calculated value significantly underestimates the experimental data in the large specific heat region. Whereas, when the value of mass flux is larger than 1000 kg · m−2 · s−1, the calculated value agrees well with the experimental data. (CSPE)
Vibration Analysis and Measurement Investigation of Gas Turbine Combustor Liner
Authors: Liu Weibing , Zhao Shizhi , Cheng Lu , Ai Song , Fan Xiaoping
Published: September 2017

Acoustic coupling effect in the combustion of fuel is the root of causing the combustor liner vibration. When the excitation frequency and the combustor liner structure natural frequency coincides or nearly, the combustor liner will resonate even cause structural damage. In order to regulate natural frequencies of combustor liner structure to avoid the oscillation frequency effectively that under the working condition, combustor liner design must include appropriate research and experimental verification of its vibration characteristics. The effectiveness of the combustor liner vibration design method and the reliability of combustor liner safe operation are verification effectively by vibration analysis and measurement investigation of gas turbine combustor liner. Technical support and follow-up to ensure safe operation of the new combustor liner design can be provided.
Experimental Investigation on the Performance of the Organic Working Fluid Scroll Expander Under the Variable Conditions
Authors: Bo Zemin , Wang Yuping , Sang Zhenkun , Lv Xiaojing , Weng Yiwu
Published: September 2017

The expander is a key component of the Organic Rankine Cycle (ORC) power generation system, which has great influence on the system performance. Based on an experiment on a ORC system using the dry working fluid R600a, the thermodynamic parameters at the inlet and outlet of the scroll expander, and the output power under the experimental conditions were obtained. The performance of the scroll expander under variable operating conditions was studied. The effect of the superheat amount, inlet temperature, and inlet pressure on the performance of the scroll expander was analyzed. The results show that the scroll expander has good performance under variable operating conditions. The inlet pressure has the greatest influence on the performance of the scroll expander, followed by the inlet temperature, while the working fluid superheat has the least effect. A change in inlet pressure of about 50kPa results in about 20W of output power at the same inlet temperature variation range. While a change in inlet temperature of about 20 ° C can result in about 15W of output power at the same inlet pressure variation range. The results can provide a reference for the design and operation of the scroll expander. (CSPE)
Performance Study on Intermediate Temperature Solid Oxide Fuel Cell and Gas Turbine Hybrid System Fueled With Biomass Gas
Authors: Ding Xiaoyi , Lv Xiaojing , Weng Yiwu
Published: September 2017

In this work, the detailed model of intermediate temperature solid oxide fuel cell (IT-SOFC) and gas turbine (GT) hybrid system with biomass gas (wood chip gas) as fuel was built, with the consideration of fuel cell potential loss such as polarization loss and heat loss. Detailed performance of key component such as reformer, fuel cell and gas turbine of the hybrid system was studied under different biomass gas fuel compositions and steam/carbon ([S]/[C]) ratios. The results show that the hybrid system can reach the efficiency of 59.24% under the designed working condition. The biomass gas from different sources and processes usually have varied fuel concentrations, especially for methane (CH4), hydrogen (H2), carbon monoxide (CO) and water (H2O), which could significantly affect the performance of hybrid system. Results show that the change of H2 proportion has the most significant influence to system output power, CO and CH4 have similar influence trend. System electrical efficiency increases slightly with the change of H2 proportion while decreasing significantly with the increase of CO and CH4 proportion. The increasing composition of CH4, H2 and CO in biomass gas fuel benefits the output power of hybrid system, but results in the higher risk of overheat as well, which might cause safety problems. The composition of water in biomass gas affects the [S]/[C] ratio of system, and results show that maintaining the [S]/[C] ratio at a certain level can guarantee the temperature of key components in the hybrid system below the limits, which can satisfy the safety standards. The results show this technology has a good application prospect. (CSPE)
Methods to Define Failure Probability for Power Plant Heat Exchangers
Authors: John Carolyn J. , Guzman-Leong Consuelo E. , Esselman Thomas C. , Harvey Sam L.
Published: September 2017

In response to the technical challenges faced by aging plant systems and components at nuclear power plants (NPP), the Electric Power Research Institute (EPRI) has a product entitled Integrated Life Cycle Management (ILCM). The ILCM software is a quantitative tool that supports capital asset and component replacement decision-making at NPPs. ILCM is comprised of models that predict the probability of failure (PoF) over time for various high-value components such as steam generators, turbines, generators, etc. The PoF models allow the user to schedule replacements at the optimum time, thereby reducing unplanned equipment shutdowns and costs. This paper describes a mathematical model that was developed for critical heat exchangers in a power plant. The heat exchanger model calculates the probability of the tubes, shell, or internals failing individually, and then accumulates the failures across the heat exchanger sub-components. The dominant degradation mechanisms addressed by the model include stress corrosion cracking, wear, microbiologically influenced corrosion, flow accelerated corrosion, and particle-induced erosion. The heat exchanger model combines physics-based algorithms and operating experience distributions to predict the cumulative PoF over time. The model is applicable to shell and tube heat exchangers and air-to-water heat exchangers. Many different types of fluids including open cycle fresh water, closed cycle fresh water, sea water, brackish water, air, closed cooling water, steam, oil, primary water, and condensate are included. Examples of PoF over time plots are also provided for different fluid types and operating conditions.
Structural Analysis of a Novel Ducted Wind Turbine
Authors: Menon Shruti Mohandas , Goudarzi Navid
Published: September 2017

Renewable energy technologies offer a competitive cost of energy values in large-scale power generations compared with those from traditional energy resources. In 2015, residential and commercial buildings consumed 40% of total US energy consumption. Short and long-term plans have been developed to further employing wind energy technologies for electricity generation. However, there is a significant gap in developing reliable utility-scaled distributed wind energy converters. Employing novel low-cost wind harnessing technologies in these sectors supports the renewable-energy expansion plans.

A novel ducted wind turbine technology, called Wind Tower, for capturing wind power is designed and developed in earlier works. In this work, the Wind Tower structural analysis is conducted to obtain insights to the required materials and optimum components’ dimensions at an expanded range of wind flow regimes. A stable and robust design addresses the need for developing an optimum solution to obtain a maximum output power generation at a minimum cost of energy. It will lead to a maximum return on investment. The results demonstrate a superior structural performance of the Wind Tower Technology. It withstands pressure loads from high wind speed when it is installed as a standalone structure.
Stress Distribution and Deformation Analysis of Gas Turbine Blades and Disk With FEM Method
Authors: Fengna Yang , Chengxiong Pan , Dongfang Zhang , Jian Tang , Jing Yan
Published: September 2017

This paper has studied the stress distribution and deformation of the fourth stage turbine blades and disk of a certain kind of heavy gas turbine with FEM method. The calculating model is assembled turbine blades and disk, and the analysis includes 2-D and 3-D situations. By calculating under centrifugal force and thermal loads, the conclusion of whether the turbine blades and disk were safe and the strength characteristics were drawn. The results shown that stress concentration of the structure is a problem that can’t be ignored. To enhance the security of structure, optimizing of the structure is recommended. Also, the results shown that structure deformation is caused mostly by thermal load and structure stress is caused mostly by centrifugal force. ( CSPE)
Investigation of Cold-Forming Properties of Sanicro 25: A Potential Candidate for Superheater and Reheaters in High Efficiency A-USC Fossil Power Plants
Authors: Bi Yanyan , Chai Guocai , Forsberg Urban , Darley Glenn
Published: September 2017

Sanicro 25 material is approved for use in pressure vessels and boilers according AMSE code case 2752, 2753 and VdTüV blatt 555. It shows good resistance to steam oxidation and flue gas corrosion, and has higher creep rupture strength than any other austenitic stainless steels available today. It is a candidate material for superheater and reheaters, enabling higher steam parameters of up to about 650 °C steam (ie about max 700 °C metal) without the need for expensive nickel based alloys. The effect of cold-forming on time and temperature-dependent deformation and strength behavior has been examined in a comprehensive study. The objective was to determine the maximum allowable degree of cold-forming to be used without additional heat treatment. The findings of these investigations indicate that the maximum allowed cold deformation could be possible to increase from today’s maximum 20 % (VdTüV 555), 15 % (540–675 °C) and 10 % (higher than 675 °C) respectively (ASME 2011a Sect I PG19). A solution annealing after the cold bending will recover creep ductility but will also at the same time increase manufacturing costs. Higher allowed degree of cold-forming without the need for post bend heat treatments, would allow for more narrow bending radii and thereby a more compact construction that would result in a significant decrease in production costs. This paper presents the findings in the mentioned study and is to be a background for possible coming discussions with involved entities on a revision of the max allowed deformation of this material without the need for solution annealing.
A Simulation Model for the Performance Enhancement of Turbocharged Diesel Engine
Authors: Ahmad Farrukh , Aziz Imran , Shah Samiur Rahman
Published: September 2017

Diesel engines are widely used throughout the world in the transportation and industrial sector. Over the years, engineers and researchers have made continuous efforts to maximize the efficiency of the diesel engine, but there is still room for improvement. By maximizing the efficiency we can not only reduce the fuel consumption of engine, but can also add positively to the environment by reducing the emissions from the engine.

In the present research a simulation model for the optimization of the performance of a diesel engine’s has been developed using the cylinder to cylinder approach. Physical, empirical and thermodynamic relations are used to setup the model in MATLAB. The model can predict the backflow through the valves based upon pressure difference across the valves. Multi event fuel injection technique is employed using main injection and pilot injection. The turbocharger is investigated with and without intercooler to see the effect on engine performance. The simulated results are in good agreement with already presented experimental results.

A study has been performed to analyze the effect of variation of different parameters on the efficiency of the compression ignition engine. The parameters analyzed are bore to stroke ratio, compression ratio, equivalence ratio, injection timing variation (advance, retard), inlet charge heating and turbo-charging. By using the developed technique it is easier to make decisions regarding efficiency optimization in the design phase of the engine. The testing time and cost associated with the engine can also be reduced. The study provides a thorough insight on the effect of parametric variation on engine efficiency.
A Numerical Investigation of Aerodynamic Characteristics of a Deteriorated Gas Turbine
Authors: Yonezawa Koichi , Nakai Genki , Sugiyama Kazuyasu , Sugita Katsuhiko , Umezawa Shuichi
Published: September 2017

In order to keep a high efficiency of a gas turbine, it is important to make a suitable maintenance. Gas turbine nozzle guide vanes (NGVs) and turbine rotor blades deteriorate through a long-time operation due to various causes such as a particle attachment, erosion, and a thermal stress. In the present study, a numerical investigation has been carried out to clarify the influence of the NGV and the rotor blade deterioration on aerodynamics in a 3-stage gas turbine. Geometries of the NGV and the rotor blade were measured from a real gas turbine using a 3-D scanner. The first stage NGVs and rotor blades usually deteriorate seriously and are usually replaced at certain intervals. Two kinds of the geometries of the NGV and the rotor blade of the first stage were obtained, which are the new ones before use and the used ones to be replaced. For the second stage and the third stage, the geometries before use were used in the computations. The numerical results show that the isentropic efficiency of the first stage increases and that of the second stage decrease due to the deterioration of the first stage. The efficiency of the third stage is not affected significantly. The mechanisms are discussed from the observation of the flow fields.
Effect of a Transition in a Fuel Species Fraction on the Behavior of a Bunsen-Type Premixed Flame
Authors: Ishibashi Takuya , Tomidokoro Takuya , Suzuki Takashi , Umezawa Shuichi , Yokomori Takeshi , Ueda Toshihisa
Published: September 2017

Effect of transient variation in the fraction of components in the multi-component fuels on the characteristics of a Bunsen-type burner has been investigated experimentally. Methane/ethane/propane three-component fuel, methane/ethane two-component fuel and methane/propane two-component fuel were used. The flame motion under the linear transition from one fuel mixture to another was examined. The transition time was varied from 1 s to 10 s, keeping the flow velocity and the equivalence ratio constant at 0.8 m/s and 0.85 respectively. The variation in the flame height was measured, using high speed video camera at 125 fps. Experimental results showed the overshoot of the flame height in an upward or downward direction during the transition. The magnitude of the overshoot was larger for shorter transition time and for larger difference of volume fraction of fuel components. The difference in diffusion coefficient of each fuel is supposed to play an important role for the overshoot.
Experimental Study on the Density Wave Oscillations of Supercritical Water in Vertical Upward Tubes
Authors: Kong Xiangfei , Liu Xin , Guo Kaikai , Feng Yuan , Li Huixiong
Published: September 2017

Supercritical and ultra-supercritical pressure boilers have been widely used in China because of its advantages of high capability, high thermal efficiency and low pollutants emission. In view of the high working parameters and complicated working conditions of such boilers, safe and stable operations of these boilers have become the focus of attention of related researchers and engineers for many years. As one of the most important phenomena that may occur in thermal power plants, flow instabilities of water in boilers’ water-cooled wall may result in heat transfer deterioration, thermal fatigue of pipes and even breakdown of the supercritical units, and have thus attracted much attention of developers and researchers of the boilers.

However, due to difficulties in carrying out experiments on the density wave oscillation of water under supercritical pressures, the related experimental data is very rare, and moreover, the characteristics of density wave oscillations of water under supercritical pressures has not been well understood.

A series of experiments have been conducted on the density wave oscillation of water flowing at supercritical pressures in a 6-m long vertical upward tube with 20.0-mm internal diameter. The experimental parameters cover the pressures from 23 to 27 MPa, the mass fluxes from 300 to 600 kg·m−2·s−1, and the heat fluxes from 225 to 500 kW·m−2. Three types of density wave oscillation were found in the present study: 1) stable periodic density wave oscillation, 2) attenuated density wave oscillation, 3) divergent density wave oscillation. Effects of pressures, mass fluxes and heat fluxes on the density wave oscillation were analyzed. With the increase in pressures and mass fluxes, the density wave oscillation of supercritical pressure water can be postponed, and is difficult to occur. And the density wave oscillation will be triggered and enhanced by increasing the heating flux. The mechanism of density wave oscillation of supercritical pressure water in tubes was also analyzed, and a dataset was established for the verification of related numerical calculations and modeling.
Experimental Investigation of Activation Solution for On-Line Activating SCR-DeNOx Catalyst
Authors: Chen Dong Lin , Ye Tuo , Zeng Xi
Published: September 2017

Currently, SCR-DeNOx technology of flue gas has been widely applied in coal-fired power plants in China for its higher denitrification efficiency, lower ammonia escape and more stable operation performance. In order to overcome the shortages of the off-line method, an on-line method based activating was proposed. However, many key technologies also need to be researched that one of them is a cheap and efficient activating solution. First, activating solutions were prepared by means of single factor and experimental investigations of catalysts activation were conducted. Second, impacts of the catalysts, which were activated by the above mentioned solutions, NO removal and activity were tested and compared with that of the inactivated catalyst. The effect of active components (vanadium, tungsten, molybdenum, oxalic acid) and flue gas conditions on the activation of catalyst were investigated. Then, analysis of these catalysts by scanning electron microscopy (SEM), the specific surface area (BET), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were conducted. Finally, an ideal activating solution was found out through the analysis of the efficiency of denitrification and the macro and micro changes from catalysts.

The following conclusions were obtained through the above mentioned activation experiments: 1) NO removal by activated catalysts is higher than that of inactivated catalyst; the De-NOx efficiency can be up to 99% in the following conditions: the reaction temperature (370 °C), the proportion of the active solution component (1.0%-V, 9%-W, 6%-Mo), the oxygen concentration (4%-O2) and the ratio of ammonia and nitrogen (NH3:N2 = 1:1); 2) the airspeed and the initial concentration of NO had little influence on catalyst activation; 3) the specific surface area and pore size of the activated catalyst were significantly increased that the active components of the catalyst surface were effectively added. Our investigation results to illustrate that the enhancement of active components, broadening of acid sites distribution, and including the surface labile oxygen and small pores opening to be the reason for high denitrification efficiency.
Thermal Performance of Steam Receiver in Tower-Type Solar Power Plants
Authors: Yan Kai , Wu Xiaojiang , Liu Jianbin
Published: September 2017

In this paper, the thermal performance of steam receiver in tower-type solar power plants has been performed using the tower-type solar receiver design program developed by Shanghai boiler works Co Ltd. In the program, the integrated effect of three types of heat transfer, i.e. heat conduction, convection and radiation, in the process of heat transfer of receivers has been considered. With integrating the characteristics and the working conditions of receivers of both steam and molten salt, the developed program can be used to perform the thermal performance calculations for the receivers of both working fluids. The proposed program was validated through Solar Two project and the satisfactory results achieve. A steam receiver in a tower-type solar power plant with double superheats is selected as an example for thermal performance calculation. In view of the receiver operating in subcritical status, the thermal performance calculation is carried out for two sections, the one for evaporation and that for superheat. In evaporation section, the working fluid is circulated with a circulating pump at a very high circulating ratio. At the outlet of panels, the qualities of working fluid can reach to maximum about 0.35. Besides, the great difference of qualities of working fluid at the outlet of panels is observed. Even for some pipes of some panels, the working fluid at the outlet is in liquid phase. The distribution of metal temperature at fin end of panels in the evaporation region varies dramatically from place to place and reaches to over 520 °C. In superheat region, the temperature of the outer front crown of tubes is concerned. The highest front point temperature of pipe, which reaches to maximum over 660 °C, is in the middle region of the last parts of the primary superheat pass. The thermal efficiency distribution of the receiver, including the evaporation and the superheat regions, are also performed. The results show that the averaged efficiency is about 86%. Besides, the phenomenon of negative thermal efficiency happens in both two regions. That is because the solar incidence cannot compensate the natural heat loss due to incident radiation reflection, the pipe wall infrared radiation and convective heat loss.
Computer Simulation of Diesel Fueled Engine Processes Using MATLAB and Experimental Investigations on Research Engine
Authors: Venkataraman Shankar , Ramawarrier Reghu , Kozhikkoottungal Satheesh Vivek , Mundupalam Nikhil Mathew , Bhure Siddaling
Published: September 2017

The depletion of conventional fuel source at a fast rate and increasing environmental pollution have motivated extensive research in combustion modeling and energy efficient engine design. In the present work, a computer simulation incorporating progressive combustion model using thermodynamic equations has been carried out using MATLAB to evaluate the performance of a diesel engine. Simulations at constant speed and variable load have been carried out for the experimental engine available in the laboratory. For simulation, speed and Air/Fuel ratios, which are measured during the experiment, have been used as input apart from other geometrical details. A state-of-the-art experimental facility has been developed in-house. The facility comprises of a hundred horsepower water cooled eddy current dynamometer with appropriate electronic controllers. A normal load test has been carried out and the required parameters were measured. A six gas analyzer was used for the measurement of NOx, HC, CO2, O2, CO and SOx. and a smoke meter was used for smoke opacity. The predicted Pressure-Volume (PV) diagram was compared with measurements and found to match closely. It is concluded that the developed simulation software could be used to get quick results for parametric studies.
Advanced Direct Drive Electric Machine Enabling High Torque at Low Speeds
Authors: Tschida Colin , Ouyang Wen , Englebretson Steven
Published: September 2017

Ocean and wind energy require reliable, efficient electric conversion systems to be viable resources. Direct drive electric generators offer both benefits; however, it is difficult to generate the required torque at the low speeds typical of these resources. In this DOE sponsored project, ABB US Corporate Research partnered with Resolute Marine Energy (RME) and Texas A&M University to investigate the suitability of direct drive electric power generation for a paddle-type wave energy converter (WEC). This WEC provides high torque in a relatively chaotic, oscillating manner and requires a machine capable of handling high peak torques of approximately 40,000 N·m at speeds typically not exceeding 3 rpm. The baseline concept uses a hydraulic power take-off coupled with a generator and convertor; a direct drive electric solution may be beneficial. As a first step in designing a suitable direct drive generator for this application, we have begun with a smaller scale prototype targeting one tenth of the speed and torque, and we investigated a machine topology that may be promising in the operating regime of the full-scale machine. To this end, we designed and tested an integral generator and magnetic gear which is rated at 3,800 N·m at 30 rpm and completed a paper design for a machine of the required scale. This paper describes the mechanical design and testing of the prototype machine and provides some reflection on necessary design changes for the full-scale machine.
Use of Seismic Analyses for the Wind Energy Industry
Authors: Hu Weifei , Pryor S. C. , Letson F. , Barthelmie R. J.
Published: September 2017

This paper proposes new seismic-based methods for use in the wind energy industry with a focus on wind turbine condition monitoring. Fourteen Streckeisen STS-2 Broadband seismometers and two 3D sonic anemometers are deployed in/near an operating wind farm to collect the data used in these proof-of-principle analyses. The interquartile mean (IQM) value of power spectral density (PSD) of the seismic components in 10-minute time series are used to characterize the spectral signatures (i.e. frequencies with enhanced variance) in ground vibrations deriving from vibrations of wind turbine subassemblies. A power spectral envelope approach is taken in which the probability density function of seismic PSD is developed using seismic data collected under normal turbine operation. These power spectral envelopes clearly show the energy distribution of wind-turbine-induced ground vibrations over a wide frequency range. Singular PSD lying outside the power spectral envelopes can be easily identified, and are used herein along with SCADA data to diagnose the associated sub-optimal turbine operating conditions. Illustrative examples are given herein for periods with yaw-misalignment and excess tower acceleration. It is additionally shown that there is a strong association between drivetrain acceleration and seismic spectral power in a frequency band of 2.5–12.5 Hz. The long-term goal of the research is development of seismic-based condition monitoring (SBCM) for wind turbines. The primary advantages of SBCM are that the approach is low-cost, non-invasive and versatile (i.e., one seismic sensor monitoring for multiple turbine subassemblies).
Solar Thermal Collector With Multifunctional Absorber Layers
Authors: Sobhansarbandi Sarvenaz , Martinez Patricia M. , Papadimitratos Alexios , Zakhidov Anvar , Hassanipour Fatemeh
Published: September 2017

Solar water heaters (SWHs) are a well-established renewable energy technology that have been widely adopted around the world. In this study we have significantly improved the Evacuated Tube solar Collectors (ETCs) by utilizing the “dry-drawable” Carbon Nanotube (CNT) sheet coatings to increase the solar energy absorption and Phase Change Materials (PCMs) to increase the heat accumulation for application in solar water heaters. The proposed solar collector utilizes a phase change material namely Octadecane paraffin, with melting temperatures of 28°C which is categorized as non-toxic with long-term chemical stability PCM. As PCMs particularly in powder form may not be effective by itself due to the poor heat transfer rate, low thermal diffusivity and thermal conductivity, by combining CNT layers with the high thermal diffusivity and thermal conductivity compare to phase change materials, we are able to overcome the shortcomings of PCMs and design an innovative and efficient solar water heater. With the current technology, we can provide a near ideal black body surface, absorbing a maximum of 98%, between 600–1100 nm, of solar light striking the surface, and providing additional spectral absorption which improves the performance of the solar heater. Applying CNT sheets in conjunction with PCM enables heat storage directly on the collector for a more constant output, even on a cloudy day and prolonged output of heat at night.
Instrumentation for the Advancement of Shell and Tube Heat Exchanger Design or for Implementing an Upgrade via a Retrofit Process
Authors: Harpster Timothy J. , Harpster Joseph W. C.
Published: September 2017

This paper presents the instruments developed for shell and tube heat exchangers and their measurements made in operating large scale HX units. These instruments provide in-situ, long-term direct measurement of temperatures and fluid flow rates that are important for evaluation of the desirable and undesirable effects of a HX design. Unique results of this instrumentation are the 3-dimensional measurements of temperature at the inlet, outlet, and along the length of heat exchanger tubes, total tube side flow, and individual tube flow measurements. The temperature measurements are interpolated in a 3-D computational space for design assessment and engineering evaluation. These results have been used to design upgrades for underperforming steam surface condensers. Data from these instruments, the evaluation process, and design effort could lead to development of a new class of better performing heat exchanger designs.
Optimization of Kaplan Hydro-Turbine at Very Low Head With Rim-Driven Generator
Authors: Abbas Ahmad I. , Sakamoto Tomoki , Saravani Mandana S. , Amano Ryoichi S. , Millevolte Joseph , Lequesne Bruno
Published: September 2017

The objective of the paper is to study the design and optimization of Kaplan hydro turbines for very low head (less than 3 meters), with a particular emphasis on the use of rim-drive electrical generators. The work is based on Computation Fluid Dynamics (CFD) analysis of a variety of design parameters for maximum output power and efficiency. Two designs are presented in the paper. One is a 90-cm (35-inch) diameter vertical-oriented Kaplan hydro turbine systems as an intended product capable of generating over 50 kW. The other is a smaller, 7.6-cm (3-inch) diameter horizontal-oriented system for prototyping and laboratory verification. Both are analyzed through CFD based on Large Eddy Simulation (LES) of transient turbulence. Certain design for the runner and the stator as well as guide vanes upstream of the turbine were studied to get the most from the available head. The intent is to use 3D-printing manufacturing techniques, which may offer original design opportunities as well as the possibility of turbine and water conduit design customization as a function of the head and flow available from a specific site.
Performance of a Supercharged Engine Fueled With a CTL Binary Mixture at Different Injection Pressures
Authors: Soloiu Valentin , Moncada Jose , Muiños Martin , Gaubert Remi , Williams Johnnie , Breen-Lyles Mary , Wagenmaker Mindy
Published: September 2017

Performance of an experimental diesel engine was investigated when fueled with CTL20 (80% ULSD#2 (ultra-low sulfur diesel) blended with 20% Fischer-Tropsch coal-to-liquid (CTL) fuel. CTL fuel was selected given its potential as an alternative fuel that can supplement the ULSD supply. Combustion and emissions were studied in a common rail, supercharged, single cylinder DI engine with 15% exhaust gas recirculation operated at 1500 RPM and 4.5 bar IMEP in reference to a diesel baseline. The injection pressure was varied from 800–1200 bar while injection timing was tested from 15° to 22° CAD BTDC to optimize combustion. Similar in-cylinder pressures and temperatures were observed for both fuels at the same injection pressure and timing; the maximum heat release and in cylinder pressure and temperatures increased with higher rail pressure. CTL20 had a retarded premixed burn peak by 5 to 8 J/CAD compared to diesel at the same injection pressure and timing. This can be related to a delayed ignition of CTL20 which allowed for higher peak premixed combustion. In-cylinder convection and radiation heat fluxes were stable across injection pressures for both fuels around 1.7 MW/m2 and 0.4 MW/m2, respectively. NOx decreased with CTL20 at higher injection pressure while soot was relatively increased at lower injection pressure. CTL20 decreased BSFC by 3–5% compared to ULSD#2 at 800–1200 bar injection. The mechanical efficiency was maintained around 65% for ULSD#2 as well as for CTL20 during operation at all injection pressures. The study suggests that CTL fuel can be used at 20% as a binary mixture in ULSD#2 while sustaining performance in the experimental engine.
Sorption Enhanced Steam Reforming of Propane Using Calcium Looping
Authors: Burra K. G. , Gupta A. K.
Published: September 2017

Sorption enhanced steam reforming of propane over Ni catalyst using in-situ carbonation of CaO provides both carbon capture, and enhanced H2 content in the product gas, and enhanced carbon conversion efficiency. Choosing propane over methane for sorption enhanced reforming provides easier fuel handling capability and higher throughput of H2 per unit volume of fuel. Such advantages help in building domestic scale hydrogen production source for sustainable energy production. The effect of propane addition on CaO carbonation and poisoning possibilities in reformation integrated with CO2 capture is explored in a packed-bed reactor. The motivation of propane addition is to model petroleum gas to address the feasibility of carbon capture integration with hydrocarbon reforming processes. Initially, different partial pressures of steam and propane will be used to study the kinetic parameters in a fixed bed reactor at different temperatures. The formed kinetic models will be used to compare the integrated CO2 capture results and the thermodynamic results to evaluate the efficiencies of such process. Higher temperatures provide better conversion efficiency, but the equilibrium of CaO carbonation suggests steam reforming enhancement and CO2 capture needs to be below 1073 K in order to avoid the backward reaction of CaCO3 releasing CO2. The balance between endothermic reformation reaction and exothermic water-gas shift and CaO carbonation reactions is the optimizing parameter for improved conversion to high H2 content. Temperatures higher than 873 K provided higher conversion with lower CO2 capture and H2 content while lower than 873 K provided lower methane conversion and higher CO2 capture and H2 content. Increase in steam to carbon ratio increased CH4 conversion and reduced CO content without affecting sorption with no further reduction in CO2 observed for most of the sorption cycle. These results supplement the available data in the literature to provide superior reaction conditions to improve the process efficiency in hydrogen production.
Analysis of the Aerodynamic Losses in a Supersonic Turbine
Authors: Sousa Jorge , Paniagua Guillermo , Collado-Morata Elena
Published: September 2017

The current development of detonation based combustors has triggered the necessity to develop new turbomachinery design procedures to achieve operable and efficient fluid machines. The high-speed flow typically observed at the outlet of a rotating detonation combustors leads to a rather challenging turbine design. The present paper reports the development of a tailored methodology to predict the non-isentropic operation of turbines exposed to supersonic inlet conditions. This one-dimensional design procedure starts by identifying the operable design space, and uses empirical loss models to estimate the main sources of inviscid and viscous losses. The turbine performance is analyzed for different design choices and compared with three dimensional computational fluid dynamic results.
A Novel Model for Man-Hour Evaluation of Nuclear Power Equipment Procurement: Practice From China Nuclear Power Projects
Authors: Zhang Rongxin , Zhou Hui , Zong Yueliang
Published: September 2017

Conventional methods for man-hour evaluation of purchase management include purchase package subtotal method and total purchase price proportion method, etc., however, these methods are limited to effectively analyze the man-hour of the procurement management in complicated industrial projects, such as nuclear power plants. Based on the experience of data collection in several nuclear power plant projects, a novel model for evaluating the equipment procurement management man-hour is proposed based on the Work Breaking-down Structure (WBS) in this paper. The unit standard man-hour for each WBS element is rigorous defined by statistical investigation of the data collection, then a set of specified adjust coefficients are applied to calculate the man-hour of the purchase contract management. The model is then analyzed and verified by a realistic equipment procurement contract, where the calculated results agree well with the practical experience. Moreover, the new model is employed to a nuclear power plant project in progress in China, both the man-hour of the equipment procurement management and the human resource demand are calculated to support the reasonable human resource arrangement for the entire construction period, which plays significant role in price quoting and cost control of procurement in Engineering-Procurement-Construction (EPC) projects. Finally, each result of a single-project obtained base on the new model can be accumulated for evaluating the multi-projects human resource demand and distribution.
Techno-Economic Assessment of Utilizing Wind Energy for Hydrogen Production Through Electrolysis
Authors: Ziazi Reza , Mohammadi Kasra , Goudarzi Navid
Published: September 2017

Hydrogen as a clean alternative energy carrier for the future is required to be produced through environmentally friendly approaches. Use of renewables such as wind energy for hydrogen production is an appealing way to securely sustain the worldwide trade energy systems. In this approach, wind turbines provide the electricity required for the electrolysis process to split the water into hydrogen and oxygen. The generated hydrogen can then be stored and utilized later for electricity generation via either a fuel cell or an internal combustion engine that turn a generator. In this study, techno-economic evaluation of hydrogen production by electrolysis using wind power investigated in a windy location, named Binaloud, located in north-east of Iran. Development of different large scale wind turbines with different rated capacity is evaluated in all selected locations. Moreover, different capacities of electrolytic for large scale hydrogen production is evaluated. Hydrogen production through wind energy can reduce the usage of unsustainable, financially unstable, and polluting fossil fuels that are becoming a major issue in large cities of Iran.
Simulation and Characterization of a Hybrid Concentrated Solar Tower System for Co-Generation of Power and Fresh Water
Authors: Mohammadi Kasra , McGowan Jon G.
Published: September 2017

The goal of this study is to evaluate and compare the thermodynamic performance of three feasible hybrid solar power tower-desalination plants for co-generation of power and fresh water. In these hybrid configurations, either multi effect desalination (MED) or thermal vapor compression (TVC)-MED unit is integrated to the Rankine cycle power block. The particular focus is on comparison between single plant and hybrid plants in terms of energy efficiency and penalty in power production to determine the more efficient configuration. The achieved results showed that integration of MED unit to the power cycle is thermodynamically more efficient, due to less reduction in power production and efficiency than the TVC-MED configurations. Also, for hybrid solar tower-MED plat, the average penalty in power production was between 9.27% and 12.88% when fresh production increased from 10000 m3/day to 31,665 m3/day. Another important finding showed the specific power consumption (specific power penalty) of the hybrid plant decreases with increasing the fresh water production. Especially at higher fresh water production, this specific power consumption was competitive to other desalination technologies such as reverse osmosis. The proposed hybrid solar tower-MED plant offers different benefits such as possibility of eliminating the cooling system requirement of the cycle as it can be replaced by the MED unit.