bluuebunny/crossref_metadata_2025 huggingface dataset:
A Fridge Compressor Control System Based on MC56F8013
Authors: Wang Li Huo , Yao Wei , Zhang Wei
Published: November 2011

This paper describes Freescale company’s DSP device MC56F8013 implementation of a fridge compressor control system about BLDC motors without position sensors, which includes motor starting and back EMF running. The motor start-up detects the variation of rotor position according to inductance of stator core. Then when the rotor is accelerated to a certain speed, EMF mode is switched. The EMF mode estimates the rotor position by back EMF zero-crossing detection method. The experiment results prove that the proposed system based on MC56F8013 can work normally and efficiently, and guarantee the demand of domestic refrigerator.
Experimental Study on the Effect of Gas Composition Variation on Engine Emissions
Authors: Guo Jia Sheng , Qin Chao Kui , Ma Fei , Tong Chao
Published: November 2011

The pollutant emissions of a four-stroke spark ignition gas engine generator operating on biogas–LPG blends of varying excess air ratios and LPG concentrations were investigated in this paper. Experiments were carried out at a constant engine speed of 1400 rpm and a constant electric power output of 3.5 kW. The experimental results showed that NOx emissions were elevated at an excess air ratio of around 1.2 as the LPG concentration was increased. CO2 emissions decreased as the excess air ratio and LPG concentration increased, due to lean-burn conditions and LPG combustion. These results demonstrated that the addition of LPG to biogas enabled the effective generation of electricity using a gas engine generator through lean-burn combustion. The adding of LPG of 0%, 5%, and 10% in volume is interchangeable. Mixing inert gas such as N2 and CO2 in the end user side to increase the gas MN, thereby increasing its antiknock tendency, furthermore, the measures such as the installation of closed-loop control engine with oxygen sensor in the exhaust and adjust air-fuel ratio accurately and adjusting engine ignition timing, to adapt the changes in gas composition to ensure that the engine working conditions are not significantly affected, to meet the requirements of natural gas interchangeability.
The Robot Path Planning Based on Region Partition to Node Optimization
Authors: Liu Yun Shan
Published: November 2011

We put forward the concept that introducing the methods of region partition and node optimization into original optimization of AOC, in order to solve the problems that ACO’S low efficiency in original execution, huge computational complexity in the process of conclusion, mess route and easily trap into the local optimal solution. The number and location of urban node after dynamic optimization reduce the ant colony quantity and iterative time arithmetic. The optimization improves the execution efficiency of arithmetic, and at the same time the analog simulation successfully applies to the robot path planning design, which show that the method is efficient and applicable so as to create a new approach of improve ACO.
An Approach for the Numerical Computation of the Reduction of the Original Porosity due to Diagenetic and Compaction Processes in Sandstone Reserviors
Authors: Wang Da Yong , Song Yong Chen , Zhang Yi , Liu Yu , Zhao Ming Long , Qi Tian , Zhao Jia Fei
Published: November 2011

Proper analysis of the original intergranular porosity loss of sedimentary strata is an important tool to gain insight into the influence of diagenetic processes on the quality of hydrocarbon reserviors. With emergence and progress of numerical technologies for simulating diagenetic processes in sedimenraty formations, the changes in the original porosity of reserviors attributed to more diagenetic processes (e.g. dissolution processes and the stabilization from one mineral to another one) can also be quantitatively evaluated. This paper proposed a set of formulas for the numerical computation of the loss in the original intergranular porosity of sandstone reserviors by compactional processes (COPL) and by intergranular cemention processes (CEPL), which consider the gain in the intergranular porosity by dissolution processes (DIPL). Theoretical analysis based on the measured data of sandstone samples shows that the real COPL will be obviously underestimated if the COPL computed by the traditional point-count method is far below CEPL and dissolution processes generated the additional porosity. Comparably, the real CEPL will only be slightly over-estimated. The deviation in COPL resulting from a DIPL of 5.0% lies in the range 0.75% ~ 2.10%, whereas the deviation in CEPL is in the range between 0.4 and 1.6%.
Study of Gasoline Engine Waste Heat Recovery by Organic Rankine Cycle
Authors: Wang E. H. , Zhang H. G. , Fan B. Y. , Liang H. , Ouyang M. G.
Published: November 2011

Energy saving and environment protection are two important issues that today’s automobile industry must emphasize. Lots of heat energy waste with the exhaust gas when the engine is running. If this part of waste heat can be recovered, the energy efficiency will be improved. Thus plenty of energy can be saved and the global warming also can be reduced. In this paper, the organic Rankine cycle whose working fluid was R245fa was studied. It was adopted to recover the gasoline engine waste heat. The mathematical model of the organic Rankine cycle was built up in Matlab to search the optimized working condition. The pinch analysis method was used to analyze the outlet temperature of the exhaust gas. The results indicate that organic Rankine cycle is a good way to recover the gasoline engine waste heat, especially in the high load conditions. The temperature of the exhaust gas can be apparently decreased.
Effects of Spark Advance Angle on Combustion and Emission Characteristics of a Compressed Natural Gas Engine
Authors: Sun Xiao Na , Zhang Hong Guang , Wang Xin , Wang Dao Jing , Zheng Guo Yong , Sun Xiao Na
Published: November 2011

The effects of spark advance angle on combustion and emission characteristics of a compressed natural gas engine have been investigated experimentally in this paper. The experimental data was conducted under various excessive air coefficient conditions using an electronic ignition system developed self-dependently. The results show that the peak cylinder pressure and peak rate of pressure rise ascends with the increase of spark advance angle in a certain extent, and their corresponding location are advanced. The CO emission keeps almost the same as the spark advance angle varies in the overall mode range. The HC and NOx emissions ascend with the increase of spark advance angle under the condition that excessive air coefficient is near the theoretical value. Under the lean-burn condition, the HC and NOx emissions are almost the same while the spark advance angle varies.
Comparative Study on Schemes of Seismic Response Reduction for the Railway Extradosed Cable-Stayed Bridge
Authors: Zhang Yong Liang , Chen Xing Chong , Hou Wen Jie , Lv Guo Dong
Published: November 2011

Based on mechanical properties of railway extradosed cable-stayed bridge with the rigid continuous beam system in the high-intensity earthquake zone, three kinds of scheme on seismic response reduction including viscous dampers, lock-up device and friction sliding bearings is presented in the text and effectiveness of seismic response reduction is analyzed by using non-linear time history response analysis . The results show that three types of isolation devices are significantly effective for improving seismic performance of the railway extradosed cable-stayed bridge. Seismic response reduction of viscous damper and Lock-up device is better, that of friction sliding bearing is second. but the type of viscous dampers is most optimal considering from normal use for structure and distribution of the seismic response in the structural system.
Pure Working Fluid Selection for the Organic Rankine Cycle in Waste Heat Recovery of Diesel Engine
Authors: Liang Hong , Liu Xing , Zhang Hong Guang , Liu Bin , Chen Yan , Wu Yu Ting , Wang Wei
Published: November 2011

According to the analysis of heat balance, about 1/3 of the fuel combustion heat is taken away into the ambience by exhaust gas of diesel engine. Depending on the characteristics of the diesel, this paper uses a special system to recover this waste heat, in which the organic Rankine cycle is combined with a single screw expander. The economy should be improved by using this system in the diesel. The model of this system is designed in Matlab combined with REFPROP. Using this way, the thermodynamic parameters should be calculated and the thermodynamic properties of this system with different working fluids should be analyzed. At last, R245fa, R245ca, R123 and R141b are selected as the alternative refrigerants used in this system.
Study on Preparation of Super Clean Coal with Selective Flocculation-Flotation Technology on Taixi Anthracite
Authors: Zhang Jin Xia , Liu Shu Xian , Nie Yi Miao , Niu Fu Sheng
Published: November 2011

Based on the coal petrology character of Taixi anthracite, the selective flocculation-flotation preparation of super clean coal is studied. The influences factors of the type and dosage of dispersant, the type and dosage of flocculant, pulp density etc etc on its effect is analyzed, and, through the orthogonal experimental methods, the salience order, interaction, and the optimum combination of the main factors is revealed. The finally test results indicate that we can obtain an ash about 1.29% at a yield of 41.85%％ super clean coal, thus will provide basis for the future super clean coal industrialization.
Performance Improvement on Edge-Based Human Detection Using Local Contrast Enhancement
Authors: Yuan Xue , Wei Xue Ye , Song Yong Duan
Published: November 2011

This paper presents a local contrast enhancement method, which is able to improve the detection performance of edge-based human detection. First, a neighborhood dependent local contrast enhancement method is used to enhance the images contrast. Next, the cascade AdaBoost classifier is used to discriminate between human and non-human. Experimental results show that the performance of our method is about 5% better than that of the conventional method.
Emission Performance of a Diesel Engine with Pressure-Wave Supercharger
Authors: Lei Yan , Zhang Hong Guang , Zhou Da Sen , Bai Xiao Lei
Published: November 2011

Pressure-wave supercharger (PWS) is one technical way to boost the engine intake air pressure. PWS has several advantages such as less emission (especially NOx emission), rapid response when load changes, higher torque even at low engine speed. In this research a 493 diesel engine is charged by a pressure-wave supercharger (PWS). The emission performance of the PWS diesel engine is mainly investigated. Together with experimental test, the CFD simulation is completed basing on a 3D model of the PWS rotor channel. The CFD simulation results show that the inner EGR phenomenon happens especially when PWS runs at middle PWS rotational speed with part load. The test results demonstrate that the PWS diesel engine performs well with less NOx and soot emissions than the turbocharged diesel engine.
Stability Analysis of Water-Based Nanofluids Prepared by Using Supersonic Dispersion Method
Authors: Wu Wei Dong , Liu Si Mei , Hong Huan Xi , Chen Sheng Xiang
Published: November 2011

Several water-based nanofluids were prepared under the action of surfactant by using ultrasonic dispersion method. The absorbency and viscosity of the nanofluids prepared under different conditions were measured and analyzed. The results showed that, when the mass fractions of nanoparticles were 0.2%, the most appropriate surfactants for Al2O3, FeO, γ-Fe2O3 water-based nanofluids were SDBS (Sodium Dodecyl Benzene Sulfonate), ACT (ammonium citrate), CTAB (Cetyltrimethyl Ammonium Bromide), respectively and the optimum mass fractions of the surfactants corresponding to the three nanofluids were 0.2%, 0.1%, 0.2%, respectively, to obtain the best dispersion stability. The optimum ultrasonic condition was 60 min of ultrasonic time under 300 W of ultrasonic power or 90 min of ultrasonic time under 200 W of ultrasonic power, in which the water-based nanofluids had the largest absorbency, the smallest viscosity and the strongest stability. In addition, the greater the size of the nanoparticles the easilier the reunion, and the poorer the dispersion stability was. When the pH value was about 4, the absorbency of Al2O3 nanofluid was larger and the dispersion stability was better. The inherent mechanism of keeping stability of nanofluids was discussed.
Pressure Forecast of an Air-Cooled Steam Condenser under Wind Speeds
Authors: He Wei Feng , Dai Yi Ping
Published: November 2011

Direct air-cooled power plant is popularized in north China because of the water conservation. Different from the water-cooled condenser, the ambient air absorbs the latent heat that turbine exhaust in the heat exchangers releases. In this paper, the numerical model of a 2×600MW power plant is prepared to simulate the performance of the air–cooled steam condenser under different wind speeds. Heat transferring with phase change is very complicated so that User Define Function(UDF) is applied to calculate the heat transfer rate in the air-cooled condenser. The fan flow rate will drop obviously during the increasing of the wind speed. As a result, the heat transfer rate between the steam and the ambient air also decreases and the pressure of the condenser rises. Finally, the stable condenser pressures under different wind speeds are predicted. The result shows that the air-cooled condenser is very sensitive to the wind speed.
Development and Research on a Hermetic Horizontal Oil-Injected Scroll Compressor for Recovering Casing Gas
Authors: Gao Xiang , Feng Jian Mei , Shen Yu Hong , Peng Xue Yuan
Published: November 2011

Increasing attention has been focused on capturing solution gas vented or flared from oil wells to reduce the emission of the greenhouse gases and effectively utilize the natural energy. With the aim of recovering the gas for its economic value, this paper presents a hermetic horizontal oil- injected scroll compressor to meet the unique demands of this application which the traditional compression technology has not been able to meet. A hermetic horizontal oil-injected scroll compressor was developed, in which the special internal oil system was designed. An experimental system was designed and set up to investigate the performance of the scroll compressor. With the experimental results, the effect of the discharge pressure and oil injection flow rate on performance of the compressor was analyzed and applied to provide the basis for developing reliable and flexible hermetic horizontal oil injected scroll compressor in taking use of the oil wells casing gas.
Experimental Research on Improvement of the Heat Pump Air-Conditioner and Hot Water System
Authors: Chen Jian Bo , Li Fen , Min Kuang Wei
Published: November 2011

This paper bring forward a new system of heat pump air-conditioner and hot water combination, base on the analysis of the advantages and disadvantages of two different domestic air-conditioner heat recovery systems. With experiment research, it also summarized improvement methods and problems which should be pay attention to in the design of this kind of system.
Effect of Defocusing on Bead-on-Plate of Ti6Al4V by Yb:YAG Disk Laser
Authors: Mastrocinque Ernesto , Corrado Gaetano , Caiazzo Fabrizia , Pasquino Nicola , Sergi Vincenzo
Published: November 2011

In this study bead-on-plate tests on 3 mm-thick Ti6Al4V sheets were performed using a Yb:YAG thin disk laser in continuous mode to evaluate the effects of focus position on the bead characteristics. Among the various solid-state lasers, the disk laser has better beam quality than conventional rod geometries thanks to the absence of thermal lensing effect. An experimental plan was conducted using nine focus positions with constant power and welding speed. The beads were characterised in terms of geometry, defects, hardness and microstructure. This work is a preliminary study to select the best values of the focal position for subsequent butt welding tests. Analysing the results obtained, the best value of defocusing was -4 mm because, among full penetrated beads, it showed lower undercut and excessive penetration, lower melted area and smaller grain size in the melted area.
Measurement of Ultrasonic Attenuation Coefficient of Mud
Authors: Zhou Ming , Shao Fu Qun , Zhang Lin
Published: November 2011

Ultrasonic attenuation coefficient of media phase is an important parameter in process tomography by amplitude method. At normal temperature (25°C), the experiment adopts continuous pulse string with the frequency of 0.5 MHz to measure ultrasonic attenuation coefficient of mud (average particle size about 300µm; water content 17%; mud-sand ratio 1:9). By the formula α= (1 / Z) 20lg (P0 / PZ), the attenuation coefficient of mud is calculated to be about 4.26×10-1dBcm – 1.
Germanium-Silicon Quantum Dots Produced by Pulsed Laser Deposition for Photovoltaic Applications
Authors: Han Li Hao , Wang Jing , Liang Ren Rong
Published: November 2011

Quantum dots applied in solar cells will be of great importance to enhance the quantum tunneling efficiency and improve the photogenerated current transport. In this study, a new easy-to-operate technology was developed to fabricate germanium-silicon quantum dots in a SiOx matrix. The quantum dots were formed by first deposited germanium-rich SiO on quartz substrate using pulsed laser deposition technique and then annealed under a comparatively high temperature. We have demonstrated a stable and low-cost fabrication process which is much cheaper than the epitaxy method to provide for the fabrication of high density germanium-silicon quantum dots. Quantum dots with diameters of 3~4 nm embedded in the amorphous SiOx layer were clearly observed. The morphological features of the thin film were characterized. The optical properties were performed by Raman spectroscopy, photoluminescence spectrum and XRD test respectively to verify the crystallization of quantum dots in the SiOx matrix. Reflectance spectrum displayed a high light absorption rate in a spectra region from 300 nm to 1200 nm, evidencing that germanium-silicon quantum dots have promising features to be used as absorber for photovoltaic application.
XPS Analysis of ZnO Thin Films Obtained by Pulsed Laser Deposition
Authors: He Jian Ting , Tan Bo Xue , Su Yuan Bin , Yang Shu Lian , Wei Qin Qin
Published: November 2011

Highly c-axis oriented ZnO thin films were deposited on n-Si (111) substrate at various oxygen partial pressures by pulsed laser deposition (PLD). X-ray diffraction (XRD), Atomic force microscopy (AFM) were used to analyze the influence of the oxygen partial pressure on the crystallization and morphology of the ZnO thin films. X-ray photoelectron spectroscopy (XPS) was used to analyze relationships between chemical shifts of XPS energy spectra and stoichiometric ratios of ZnO thin films, and quantitative relationships between content of Zn, O and oxygen partial pressures. An optimal crystallized and stoichiometric ZnO thin film was observed at the oxygen partial pressure of 6.5Pa.
Semiconductor Lasers Based on the Orthogonal Dual Gloss Meter
Authors: Gao Yue Hua , Wang Yong Qing , Hao Lei , Zhou Ying Chang
Published: November 2011

The surface brightness values in different directions are different, the measurement of the existing optical gloss meter only once can not simultaneously achieve measurement from different directions, for this phenomenon using orthogonal pairs of optical measurement method, two groups of measurements should be averaged. Measuring probe is made of a 2kHz pulse modulation circuit, silicon photovoltaic cells, I / V conversion, high-pass filter, such as precision rectifier circuit. Measurement probe output signal by the dual analog switch and the ADC into the computer. System software using VB, can realize to show the average computation, numerical analysis and results of statistical functions. Semiconductor laser light source eliminates the need of optical collimating lens. Measurement of laser modulation frequency is 2kHz, much higher than the environmental stray light, using techniques based on frequency domain interference with satisfactory light scattering resisting effect,the test shows that the error caused by stray light is less than 1.5% ,when the instrument works open-ended in the light path.
Laser Doppler Velocimetry Signal Processing Based on Spectral Refinement and Correction
Authors: Song Nian Long , Zhang Da , Li Qi
Published: November 2011

In order to improve the accuracy of signal processing in Laser Doppler Velocimetry, a method based on the association of spectral refinement and correction is presented. Zoom-FFT and ratio correction are adopted to realize this method. Basic principles of zoom-FFT and ratio correction are expounded. FFT and the method are adopted to process sinusoidal signals and simulated laser Doppler signals with different frequencies separately in circumstance of MATLAB 7.0. Comparisons between the results of FFT and the method are carried out. The comparisons show that this method has the capability to improve the accuracy of laser Doppler signal processing significantly and the operation time is acceptable for LDV system.
Design and Rapid Manufacturing Structural Components of a Mini-Scale Underwater Vehicle
Authors: Cheng Yih Lin , Chang Rui Dong
Published: November 2011

Underwater vehicles have been developed mainly for underwater exploration and rescue. Many large- and middle-size vehicles are available but few are in smaller scale. As the size goes into mini-scale which is less than 20 cm, it is challenging to allocate required components within limited space, while providing designed functions at the same time. The aims of this research are to design and rapid manufacture structural components for a remote-controlled underwater vehicle in the mini-scale region. The vehicle would integrate vision capability to provide functions of underwater ecological observation and tracking. In order to design the structural components for this mini-scale vehicle, commercial CFD software was adopted to simulate flows. An improved external shape was obtained and detailed designs of the structural components were implemented. A rapid prototyping technique, Shape Deposition Manufacturing (SDM) process, was utilized to rapidly manufacture these components. The finished components were assembled with control modules and propulsion systems as an underwater vehicle and the preliminary underwater test was conducted successfully.
Modification of Nano-Titanium Dioxide Film and Processing Experimental Study of Tannery Waste Water
Authors: Xu Pei Yao , Han Xiao Xue , Ban Sa Sa
Published: November 2011

This paper was prepared by liquid phase deposition of quartz sand load nanometer titanium dioxide film, in which quartz sand as the carrier, and to Fe3+,Zn2+ as doping on the membrane was modified. The initial value of pH is 6.7,in this condition, select the heating temperature, the doping ratio of Fe3+andZn2+ to design the orthogonal experiment. CODCr removal and pH value as the evaluate index, to deal with the real tannery wastewater, discussed when Fe3+,Zn2+ co-doping, the best doping ratio of them, the best technical conditions such as heat treatment temperature; and their affect on CODCr removal rate and pH value.Under the optimum conditions, confirmed by further study that Fe3+ doped titanium dioxide modified membrane absorption band red shifts, the utilization of solar is increased, the tannery wastewater which was treated by modified membrane, its biodegradability is greatly increased.
Hybrid Desiccant Cooling System Using Condensing Heat as the Regeneration Source. Part II: Energy Saving Potential
Authors: Han Xing , Zhang Xu
Published: November 2011

Based on the system model of hybrid desiccant cooling system using condensing heat as the regeneration source, the solution is given to investigate the system characteristic. The result showed that, when the outdoor air humidity ratio is below 18.5g/kg and indoor dehumidification load is below 1.5kg/h, the energy consumption of this system is lower than the enthalpy recovery air-conditioning system. If not, due to the high energy consumption of electrical heating, the desiccant wheel using condensing heat and electrical heat is not suitable for the humid areas.
Experimental Study of Oil-Gas Cyclone Separator Performance in Oil-Injection Compressor System
Authors: Yang Xin , Feng Jian Mei , Chang Yun Feng , Peng Xue Yuan
Published: November 2011

Experimental study of the separation efficiency of oil-gas cyclone separator for oil-injection compressor system was conducted with the aim of understanding the separation process and identifying the main parameters affecting the separation efficiency. Malvern Particle Size analyzer was applied to analyze the separators’ performance. By simultaneously measuring the oil droplet size distribution and oil concentration upstream and downstream of the separators, the separation performance was assessed. The results of the study contribute to an optimized cyclone separator design.
Numerical Simulation Research on Louver Fin in Air Conditioning for Cars
Authors: Zhou Jun Jie , Wang Hui , Wang Ding Biao , Zhang Kang
Published: November 2011

Heat transfer and fluid flow on the air side for heat exchanger in the air conditioning system are numerically simulated by FLUENT commercial software. Numerical analysis is conducted on the plate louver fin, the sinusoid louver fin and the leaf louver fin when the inlet velocity rang is from 2m/s to 7m/s. Heat transfer factor and friction coefficient are respectively fitted with the Reynolds number by the correlation. The sinusoid louver fin is found to have the best comprehensive heat transfer performance. Not only the leaf louver fin’s comprehensive heat transfer performance is good, but also its pressure drop loss is 28.1%~38.8% lower than that of plate louver fin
Thermal Performance Analysis for a New External Wall Insulation System
Authors: Li Jian Guang , Tong Li Ping , Tian Li Hui
Published: November 2011

Based on the existing quality problems of external wall insulation system, a new external wall insulation system was developed through the rational use of closed air layer’s thermal insulation performance. Considering three kinds of ways of heat transfer-- convection, conduction and radiation and using the coefficient of air equivalent thermal conductivity to obtain the thermal resistance in the air layer, compared with the thermal resistance at different thicknesses in the new system using polyurethane and polystyrene board of insulation material with two different thicknesses, the authors can get the most optimal model. This paper takes the extreme value of indoor and outdoor temperature in summer as the temperature loads of this model and uses ANSYS simulation to obtain its heat flow density, gradient and temperature field, and in the meanwhile, undertakes a comparison with the present form of external wall insulation in the new code. Data indicates that in the same index of energy saving, this system can not only meet the needs of the code, but also reduce the requirement of heat insulator, as well as greatly improve anti-cracking and waterproofing ability. Thus, the new system follows the direction of the development in this field.
Variable Step-Length Efficiency Optimum Control of Traveling Wave Ultrasonic Motor System
Authors: Liu Bo , Shi Jing Zhuo , Liu Xun
Published: November 2011

To achieve the operational efficiency maximization of ultrasonic motor system, this paper analyzes optimum control of the ultrasonic motor system’s efficiency including driving circuit, while the speed closed-loop control performance is ensured. Based on regulating characteristics of open-loop speed control and fuzzy control, two optimum control methods for regulating the changing step-length of driving voltage amplitude, to shorten the elapsed time of efficiency optimization process and to improve the general operational efficiency of motor system and the speed closed-loop control performance, are also analyzed. The effectiveness of the methods mentioned in this paper are reflected using experiments.
The Simulation Research on the Performance of Chevron-Type Corrugated Plate Heat Exchanger
Authors: Wang Ding Biao , Liang Zhen Xiang , Zhou Jun Jie , Wang Hong Bin
Published: November 2011

Based on the method of CFD, a study on the structure parameters that affect the performance of chevron-type corrugated plate were carried out by simulating with the CFD software Fluent. The impact on flow and heat transfer performance were compared in different plate arrangement forms, different corrugation angles, corrugation depths and corrugation spacing for periodic boundary condition. The results show that heat transfer can be enhanced by staggering the plates. Heat transfer performance is about 1.444 times as corrugation angel is 60° to that of 30° while friction factor is 6.97 times as the angel is 70° to that of 30°. Comprehensive performance is higher at a small corrugation angel. When the ratio of corrugation length to depth is less than 3.0, skin friction factor increases with the increasing of depth, the dimple corrugated plate is about 59.2% and 58.7% higher than the common one on heat transfer and friction factor respectively.
Numerical Simulation of Air Distribution in the Series-Type Electrostatic Fabric Filter Precipitator
Authors: Hu Man Yin , Che Kai , Zhang Jing , Wang Xiu Hong
Published: November 2011

For the operation situation of the series-type electrostatic fabric filter precipitator, the deflectors in the inlet of the precipitator whose angle and spacing were changed to improve the air distribution characteristic and collection efficiency were assembled. The three-dimensional structural model of the series-type electrostatic fabric filter precipitator was built and meshed, then carried on the number simulation of air distribution characteristic with FLUENT. The simulation results show that when the deflector spacing is 0.7m and the incremental height is 0.15m the air distribution is more uniform. The numerical simulation result is reasonable and can be used as the reference to optimize the designing of electrostatic fabric filter precipitator.
Three-Dimensional Simulation of Gas-Solid Flow in the Biomass Circulating Fluidized Bed Gasifier’s Riser
Authors: Chen Wen Yi , Liu Xin , Fan Xiao Xu , Chu Lei Zhe , Yang Yi Mei , Liu Wen Ting
Published: November 2011

Using the Gidaspow model as the momentum exchange coefficient to take a full-loop simulation of miniature circulating fluidized bed gasifier (CFBG) in the lab, and taking mutual influence of different parts in consideration, it focus on the gas-solid flow structure in the riser in this paper. The heterogeneous behavior in the CFBG riser and the radial profiles of solid volume fraction under different solid inventories in simulation are showed in this paper as a replenishment of certain data which are hard to measure in experiments. The results showed it can’t form an obvious core-annulus flow because of the riser’s high height-diameter ratio and the big refeed line diameter. There are clusters growing and dissipation in a short time. A turning point of pressure drop may be seem as a separation of dense area and dilute area.The three-dimensional (3D) simulation revealed the solid flux and the pressure drop agree with the experimental data.
Experimental Study on Modified Model of Indoor Bio-Aerosol Dispersion
Authors: Ding Yan , Tian Zhe , Zhu Neng
Published: November 2011

The main transmission route of infectious disease is the dispersion of exhaled particulate matter with pathogen attached on. Therefore, the exploration on the dispersion routine of bio-aerosol is a significant approach for researching control method of indoor infection. Based on the continuous point-source dispersion model, this article puts forward corresponding modified methods according to different airflow patterns and make it become a reasonable predicting tool for the dispersion of bio-aerosol in indoor environment. Such predicting tool is also validated by a bacteria emanating experiment whose results show a notable improvement on predicting accuracy of the modified model. Additionally, the experiment results also indicate that the under floor air supply pattern embraces preferable controlling ability on indoor infections for each occupant in an office environment.
Simulation and Optimization of Domestic Wastewater Nutrients Removal Process: Vfas as External Carbon Source
Authors: Hu Mao Dong , Zhou Xue Fei , Zhang Ya Lei , Jiang Ming , Tan Yan Zhong
Published: November 2011

The aim of this study is to investigate the effect of nutrient removal process by addition of volatile fatty acids (VFAs) as external carbon sources, and how a model can be applied to a pilot test system to simulate the system. The results showed that: the effect of nutrients removal can be substantially increased with the addition of VFAs: before the addition of VFAs, the removal rate of TN and TP are 22% and 26% respectively; after the addition of VFAs, removal rates of TN and TP achieved 74% and 80% respectively. From an error analysis between simulated value and experimental value on the condition of external carbon addition, the average relative errors of CODcr, TN, NH3-N and NO3-N are 9.5%,23.4%,36% and 22% respectively, which illuminated the correctness of the model; optimum working conditions of the system established by the model are: internal reflux ratio is 200%,external reflux ratio is 75%,sludge retention time is 10d.
Study on Simulation Model of Hydrothermal-Treatment of Degradable Organic Wastes
Authors: Guo Shu Qing , Dong Xiang Yuan
Published: November 2011

An overall material and energy balance analysis of hydrothermal-treatment system is conducted; a model for simulating the hydrothermal-treatment process is established. The experimental hydrothermal-treatment results of lawn-grass are used to test and prove the effectiveness of the model; and a series of technical parameters are obtained including time duration, reaction temperature, content of hemicellulose, cellulose and lignin etc.. The model can be used for technical design and operation control of lignocellulose biomass hydrothermal-treatment system.
Modeling and Simulation of Selective Catalytic Reduction for Flue Gas Denitration in Power Plants
Authors: Shen Bo Xiong , Zhao Ning , Liu Ting , Wu Feng Peng , Zuo Chen
Published: November 2011

Based on Eley-Rideal kinetic mechanism, one dimensional mathematical model for selective catalytic reduction reaction was established, in order to simulate the SCR process in the catalyst channel. The thermal effect on the reaction and the side effect of ammonia oxidation in the channel were considered simultaneously in the modeling. The model was testified to be reliable by compared with the experimental data. By the model, the concentration and temperature distributions in the channel were simulated. The effects of catalyst structure parameters, such as the pitch, the shape of catalyst channel and the monolithic catalyst type, on de-NOX efficiency were studied emphatically. The simulation results would be as an important reference for the design of SCR catalyst in the practical application.
The Numerical Simulation Analysis of Excavation Process of Loess Tunnel
Authors: Guo Jian , Wang Qi Cai
Published: November 2011

The bench method dynamic construction process of Xin Baotashan tunnel which located in the grade IV surrounding rock is simulated by using the finite element method. The variation of displacement and stress field of the surrounding rocks and the internal force of the lining structures during every excavation step is calculated. The state of the surrounding rocks can be predicted by the numerical simulation results, and the construction plan and construction sequences can be guided by the analysis results. At the same time the reasonability and feasibility of the design parameters can be judged by analyzing the internal forces of the lining structures. Analysis and experimental results showed that the stability of the surrounding rocks is good by using the bench method construction to the IV grade surrounding rocks and the design parameters of the lining structures are feasible.
Design and Realization of Mine Water-Inrush Visualization Simulation System
Authors: Zhou Yao Dong , Li Zhong Xue , Li Cui Ping , Cao Zhi Guo
Published: November 2011

There exists a high risk of water-inrush in mining activities. Therefore, it is critical to develop a conceptual model of Mine Water-inrush, especially for the underground environment. The general structure of Mine Water-inrush Simulation System consists of core network, the underground monitoring network, and the operational system. Through the application of data processing system, simulation system and the application system, the original data can be processed. The results is then passed to the operators and managers, which require them increase the understanding of factors leading to accidents and consequently take action to improve mining safety. This new water-inrush model captures three characteristics to regard the mine water-inrush: the inrush sources, inrush process, and submerging process. Virtual length has been applied to the model, which is combined with a Traversal Algorithm, can be used to calculate the area of increased influence over time for each process. Based on the collected data from a real mine, the underground excavations and a virtual water-inrush disaster process were simulated, which shows that the system operates reliably.
Dissolved Oxygen Convection and Diffusion Numerical Simulation of Water and Air Mixture Flow in Circular Pipe
Authors: Yin Ze Gao , Cao Xian Wei , Cheng Dong Sheng , Wang Le
Published: November 2011

In Fluent, the 3-D RNG k–ε mathematical model is employed to compute water and air mixture pipe flow. The dissolved oxygen convectionaεnd diffusion model is established to simulate the concentration distribution of dissolved oxygen with user defined scalar method. Velocity, pressure and dissolved oxygen concentration are computed. Then, dissolved oxygen concentration and pressure are compared with the data of physical model, and they agree with each other approximately, showing it is valid and reliable to compute the mixture pipe flow and dissolved oxygen concentration with the model .Furthermore, under a specific condition, velocity, pressure and dissolved oxygen concentration of water and air mixture pipe flow are computed and their characteristics are analyzed.
Robust Data Reconciliation in Linear Process
Authors: Zhou Ling Ke
Published: November 2011

Data reconciliation is based on spatial redundancy to adjust process data to improve the quality of measurement corruption due to measurement noise. However, the presence of gross errors can severely bias the reconciled results. Robust estimators can significantly reduce the effect of gross errors and yield less biased results. In this paper, a method is proposed to solve the robust data reconciliation problem. By using the proposed method, the robust estimator problem can be transformed into least squares estimator problem which leads to the convenience in computation. Simulation results for a linear process verify the efficiency of the proposed method.
Neural Network Based Modeling in Wire Electric Discharge Machining of SiCp/6061 Aluminum Metal Matrix Composite
Authors: Shandilya Pragya , Jain P.K. , Jain N.K.
Published: November 2011

Wire electric discharge machining (WEDM) process is considered to be one of the most suitable processes for machining metal matrix composite (MMC) materials. Lot of research work has been done on WEDM process, but very few investigations have been done on WEDM of MMCs. The purpose of this research work is to develop the artificial neural network (ANN) model to predict the material removal rate (MRR) during WEDM of SiCp/6061 Al MMC. In this work four input parameters namely servo voltage, pulse-on time, pulse-off time and wire feed rate were used to develop the ANN model. The output parameter of the model was MRR. A Box-Behnken design (BBD) approach of response surface methodology (RSM) was used to generate the input output database required for the development of ANN model. Training of the neural network models were performed on 29 experimental data points. The predicted values obtained from ANN model show that model can predict MRR with reasonable accuracy. The good agreement is obtained between the ANN predicted values and experimental values. In the present case, the value of correlation coefficient (R) equal to 0.9968, is closer to unity for ANN model of MRR. This clearly indicates that prediction accuracy is higher for ANN model.
Modeling and Optimization of Wire Electrical Discharge Machining of Cold-Work Steal 2601
Authors: Golshan Abolfazl , Gohery Scott , Amran Ayob
Published: November 2011

In this study, the appropriate input parameters for achieving minimum surface roughness and high material removal rate are selected for wire electrical discharge machining of cold-work steel 2601. Mathematical modeling acquired by experimental result analysis is used to find the relation between input parameters including electrical current, gap voltage, open-circuit voltage and pulse-off time and output parameters. Subsequently, with exploitation of variance analysis, importance and effective percentages of each parameter are studied. The combination of optimum machining parameters is acquired using the analysis of ratios of signal-to-noise. Finally, according to multiple-objective optimization, outputs acquired from Non-dominated Sorting Genetic Algorithm led in achieving appropriate models. The optimization results showed suggested method has a high performance in problem solving.
Numerical and Experimental Investigation of Inward Tube Electromagnetic Forming- Electromagnetic Study
Authors: Arezoodar Alireza Fallahi , Haratmeh Hossein Ebrahimi , Farzin Mohmoud
Published: November 2011

A numerical simulation of high-speed forming of tubes on the die in electromagnetic forming (EMF) system is presented to study effects of some electromagnetic parameters. Simulations of electromagnetic and structural parts of EMF process are carried out. Calculated currents in this process are in agreement with experimental results measured by Rogowsky coil. But calculated and simulated currents at first peak are a little more than the experimental value. Effects of material and process parameters on bead depth are investigated in detail with this validated code. It deduced that shape of the bead is affected by discharge voltage and coil parameters. As a result, the bead depth increases with the increase of the discharge voltage and decrease of number of windings.
Improved Differential Evolution Algorithm for Structural Optimization Design of Flumes with Hybrid Discrete Variables
Authors: Zhou Juan , Zhang Duo Xin , Liu Xian Liang
Published: November 2011

The traditional method applying to solve continuous variable optimization problems is not suit for flume structural optimization design with hybrid discrete variable. According to the mathematical model of structural optimum design of the prestressed U-shell flumes, differential evolution (DE) algorithm was introduced to flume structural optimization design. In order to improve the population’s diversity and the ability of escaping from the local optimum, a self-adapting crossover probability factor was presented. Furthermore, a chaotic sequence based on logistic map was employed to self-adaptively adjust mutation factor based on linear crossover, which can improve the convergence of DE algorithm. Dynamic penalty function, to transform the constrained problem to unconstrained one, was employed. The result shows that, compared with the original design scheme, the optimization design scheme can greatly reduce the amount of prestressed reinforcement. The construction cost of both the flume and the whole project can be reduced accordingly.
Finite-Element Analysis of Heat Generation by Plasma in Welding Temperature Field of Stainless Steel
Authors: Moarrefzadeh A. , Zibaei M.R.Isvand
Published: November 2011

In this paper, the plasma arc welding is studied and stainless steel temperature field is gained in this process. The available heat source models, either planar one like Gaussian or body ones like double-ellipsoidal and rotary Gaussian modes, are unable to describe the keyhole PAW process accurately. Based on the configuration feature of keyhole PAW welds, a combined heat source model is proposed for the numerical analysis of temperature fields in keyhole PAW process. Numerical simulation of welding process in SIMPELC method and by ANSYS software for gaining the temperature field of stainless steel, the effect of parameter variation on temperature field and process optimization for different cases of plasma and shielding gases(Argon, Helium), are done.
A CAD/CAPP/CNC Integrated System Based on Lightweight 3D Model
Authors: Li Zhou Yang , Tian Xi Tian , Geng Jun Hao
Published: November 2011

3D information exchanging and sharing are difficult between CAD, CAPP and CNC systems. To solve this problem, under the support of the National High Technology Research and Development Program, a new approach is brought forward. In section Ⅱ of our explorative paper, a CAD/CAPP/CNC integrated system based on lightweight 3D model is established to manage the information of the whole process of product manufacturing. Fig. 1 in the full paper gives the system’s architecture and functions. In section Ⅲ, we establish an integrated information model based on lightweight 3D model by analyzing each system’s functions and requirements of manufacturing process and the process of data flowing. In order to extract manufacturing features from design features in lightweight 3D model, a feature convertor is established in section Ⅳ. And a 3D feature recognizing prototype system was established and the feasibility of this method was verified.
Calculation of Grinding Wheel Profile and 3D Simulation for Grinding Screw Rotor Flute
Authors: Lu Ru Sheng , Yao Bin , Li Fei , Yao Bo Shi
Published: November 2011

In order to describe the forming grinding principle of screw rotor, the mathematical model of screw rotor’s helical groove and forming grinding wheel are established by differential geometry theory and numerical analysis method. And the contact line equation is derived. To optimize the traditional method of calculating forming grinding wheel by known rotor end section profile, a numerical analysis method (Accumulated Chord Length Parameter Method) has been presented in detail. This method can improve the efficiency and reliability of the calculation of forming grinding wheel axial profile. Taking the asymmetry linear screw rotor (female) as an example, this paper calculates the grinding wheel axial profile and draws it using special designed software. The simulation examples are done by CAD (Computer Aided Design) based on the secondary development technology of UG. This study provides a precise 3D model which can be used in areas such as finite element analysis and virtual testing experiments.
Artificial Neural Network Based Process Model for Arsenic Diffusion in Si1-xGex Alloys
Authors: Sharma Abhishek A. , Mane Sanjay S.
Published: November 2011

The thermal diffusion behavior of ion-implanted Arsenic (As) in SiGe alloy has been investigated and modeled. This paper introduces a neural network based model consisting of physics-based and process-based parameters for evaluating the effective diffusivity of Arsenic through SiGe accurately. The parameters that served as the input to the neural network included Ge content, diffusion temperature and anneal time. The model was validated for the germanium content of up to 45% with the reported data and the existing simulation models in Silvaco. The model incorporates all the effects associated with the change in the process parameters which affect the diffusivity of As in relaxed-SiGe. The model was found to be extremely accurate in predicting the exact dependencies of As diffusivity on physics-based and process parameters. The proposed empirical process model may find suitable application in prediction of thermal diffusion behavior of As in SiGe process-flow with emphasis on reduced computational time.