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Computational theory of cavitating flows for hydraulic turbomachinery with consideration of influence of water quality

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Science china(Technological Sciences) 2010年第12期53卷 3341-3348页

作者： WANG Lei1,2.& CHANG JinShi2.1 Huadian Electric Power Research Institute, Hangzhou 310030, china 2.college of {2. Conservancy and civil engineering, china agricultural university, beijing 100083, china 1. Huadian Electric Power Research Institute Hangzhou 310030 China2. College of Water Conservancy and Civil Engineering China Agricultural University Beijing 100083 China

Previously it was assumed that the pressure within the cavity or on the cavity surface remained constant and the vapor pressure of clean water at 2.°C and 0 m altitude was utilized as the computational boundary for cavitating flows in hydraulic turbomachinery. Cavitation was confused with vaporization, and the effect of water quality on cavitation pressure characteristics was not taken into account. In recent years, lots of experiments of cavitation pressure characteristics of different water qualities including different sand concentrations of sand water and different altitudes of clean water have been performed by the authors, and the important influences of water quality on cavitation pressure characteristic have been validated. Thus the water quality should be involved in the cavitating flows computation. In the present paper, the effect of water quality on the cavitation pressure characteristic is analyzed and the computational method and theory of cavitating flows for hydraulic turbomachinery that considers the influence of water quality are proposed. The theory is suitable for both the potential flow method and the two-phase flow method for cavitating flows simulation. Finally, the validation results for cavitating flows in a hydraulic tur- bine indicate the significant influences of water quality on the cavitating flow performance.

关键词： cavitating flows cavitation pressure water quality hydraulic turbomachinery

Integrating MODFLOW and GIS technologies for assessing impacts of irrigation management and groundwater use in the Hetao Irrigation District,Yellow River basin

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Science china(Technological Sciences) 2009年第11期52卷 3257-3263页

作者： XU Xu1,2. HUANG GuanHua1,2.& QU ZhongYi3 1 Center for Agriculture water Research, china agricultural university,{2., china 2.Chinese-Israeli International Center for Research and Training in Agriculture, china agricultural university,{2., china 3 water Conservancy and civil engineering college, Inner Mongolia agricultural {12., Hohhot 010018, china 1. Center for Agriculture water Research China Agricultural University Beijing 100083 China 2. Chinese-Israeli International Center for Research and Training in Agriculture China Agricultural University Beijing 100083 China 3. water Conservancy and civil {2. college Inner Mongolia Agricultural University Hohhot 010018 China

Due to severe water scarcity, water resources used in {2. sector have been reduced markedly in Hetao irrigation district. Application of water-saving practices (WSPs) is required for the sustainable {2. development. The human activities including WSPs and increase of groundwater abstraction can lower down the groundwater table, which is helpful to the salinity control. Meanwhile, an excessively large groundwater table depth may result in negative impact on crop growth and fragile ecological environment. In this paper, the Jiefangzha irrigation system in Hetao irrigation district was selected as a typical area, a groundwater flow model based on ArcInfo Geographic Information System (GIS) was developed and implemented to quantify the effect of human activities on the groundwater system in this area. The preand post-processing of model data was performed efficiently by using the available GIS tools. The time-variant data in boundary conditions was further edited in Microsoft Excel with programs of Visual Basic for Application (VBA). The model was calibrated and validated with independent data sets. Application of the model indicated that it can well describe the effect of human activities on groundwater dynamics in Jiefangzha irrigation system.

关键词： groundwater flow modeling MODFLOW GIS water-saving practices irrigation district

A general finite element model for numerical simulation of structure dynamics

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 440-450页

作者： WANG Fujun1, LI Yaojun1, Han K.2.& Feng Y.T.2.1. college of water Conservancy and {2. engineering, china agricultural university, beijing 100083, china 2. {2. & Computational engineering Centre, university of Wales Swansea, Swansea SA2.8PP, U.K. college of water Conservancy civil engineering China Agricultural University Beijing 100083 China civil & Computational engineering Centre University of Wales Swansea Swansea SA2 8PP UK

A finite element model used to simulate the dynamics with continuum and discontinuum is presented. This new approach is conducted by constructing the general contact model. The conventional discrete element is treated as a standard finite element with one node in this new method. The one-node element has the same features as other finite elements, such as element stress and strain. Thus, a general finite element model that is consistent with the existed finite element model is set up. This new model is simple in mathematical concept and is straightforward to be combined into the existing standard finite element code. Numerical example demonstrates that this new approach is more effective to perform the dynamic process analysis in which the interactions among a large number of discrete bodies and continuum objects are included.

关键词： finite element method, discrete element method, structure dynamics, numerical simulation.

NUMERICAL INVESTIGATION OF PERFORMANCE OF AN AXIAL-FLOW PUMP WITH INDUCER

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Journal of Hydrodynamics 2007年第6期19卷 705-711页

作者： LI Yao-jun WANG Fu-jun college of water Conservancy and {2. engineering China Agricultural University Beijing 100083 China

The interaction of flow through the inducer and impeller of an axial-flow pump equipped with an inducer has significant effect on its performance. This article presents a recent numerical investigation on this topic. The studied pump has an inducer with 3 blades mounted on a conical hub and a 6-blade impeller. The blade angle of the impeller is adjustable to generate different relative circumferential angles between the inducer blade trailing edge and the impeller blade leading edge. A computational fluid dynamics code was used to investigate the flow characteristics and performance of the axial-flow pump. For turbulence closure, the RNG k-ε model was applied with an unstructured grid system. The rotor-stator interaction was treated with a Multiple Reference Frame （MRF） strategy. Computations were performed in different cases： 7 different relative circumferential angles （ Δθ ） between the inducer blade trailing edge and the impeller blade leading edge, and 3 different axial gaps （G） between the inducer and the impeller. The variation of the hydraulic loss in the rotator was obtained by changing Δθ . The numerical results show that the pressure generated is minimum in the case of （ G = 3%D）, which indicates that the interference between inducer and impeller is strong if the axial gap is small. The pump performances were predicted and compared to the experimental measurements. Recommendations for future modifications and improvements to the pump design were also given.

关键词： axial-flow pump inducer CFD numerical simulation of flow

Effects of Curing Systems on Properties of High Volume Fine Mineral Powder RPC and Appearance of Hydrates

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Journal of Wuhan university of Technology(Materials Science) 2010年第4期25卷 619-623页

作者：刘娟红 college of civil and Environmental {2. University of Science and Technology Beijing

The effects of different curing systems on the properties of high volume fine mineral powder RPC （reactive powder concrete） and the appearances of hydrates were studied. The experimental results show that dry-heating curing promotes the development of pozzolanic reactivity of fine mineral powder; due to low cement content, 0.2. water-bind ratio and high reactive fine mineral powder content, the strength of RPC increases by around 2.0% after steam curing and subsequent dry-heating curing. Scanning electron microscopy and energy spectrum diagram showed that： after the high volume fine mineral powder RPC with 0.16 water-bind ratio underwent steam curing and dry-heating curing, there was no significant change in the appearance of hydrates; after the RPC with 0.2. water-bind ratio, the cement content of 150 kg/m3 and more steel slag powder underwent dry-heating curing, there was a certain change in the appearance of C-S-H, the structure of gel was more compact and was uniformly distributed, and the Ca/Si of C-S-H gel decreased from 1.41 to around 1.2..

关键词： curing system high volume fine mineral powder RPC appearance of hydrates

One-dimensional numerical simulation of non-uniform sediment transport under unsteady flows

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International Journal of Sediment Research 2008年第4期23卷 316-328页

作者： Hongwei FANG 1,Minghong CHEN 2.and Qianhai CHEN 31 Prof.,Dept.of Hydraulic engineering,Tsinghua Univ.,State Key Laboratory of Hydroscience and engineering,{2.,100084,china 2.PhD,college of water Conservancy and civil engineering,china agricultural Univ.,{2. 100083,china.3 Engineer,Institute of the Yangtze River Research,Wuhan,430010,china [a]Prof. Dept. of Hydraulic engineering Tsinghua Univ. State Key Laboratory of Hydroscience and engineering beijing 100084 china [b]PhD college of water Conservancy and {2. engineering china agricultural Univ. beijing 100083 china [c]Engineer Institute of the Yangtze River Research Wuhan 430010 china

One-dimensional numerical models are popularly used in sediment transport research because they can be easily programmed and cost less time compared with two-and three-dimensional numerical *** particular,they possess greater capacity to be applied in large river basins with many *** paper presents a one-dimensional numerical model capable of calculating total-load sediment *** cross-section-averaged sediment transport capacity and recovery coefficient are addressed in the suspended load *** one-dimensional model,therefore,can be applied to fine suspended loads and to hyperconcentrated flows in the Yellow ***,a new discretization scheme for the equation of unsteady non-uniform suspended sediment transport is *** model is calibrated using data measured from the Yantan Reservoir on the Hongshui River and the Sanmenxia Reservoir on the Yellow River.A comparison of the calculated water level and river bed deformation with field measurements shows that the improved numerical model is capable of predicting flow,sediment transport,bed changes,and bed-material sorting in various situations,with reasonable accuracy and reliability.

关键词： One-dimensional numerical model Sediment transport capacity Recovery coefficient Adaptation length Unsteady flow

Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions

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Science china Earth Sciences 2006年第2期49卷 193-201页

作者： LEI Tingwu1,2. LIU Han1, PAN Yinghua3, ZHAO Jun2. ZHAO Shiwei2.& YANG Yonghui2.1. The Key Laboratory of Modern Precision Agriculture System Integration Research, college of Hydraulic and civil Engineer-ing,{2., beijing 100083, china 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and water Conservation, Yangling 712.00, china 3. Geographic and Resources Management college, Yantai Normal university, Yantai 2.402., china 1. The Key Laboratory of Modern Precision Agriculture System Integration Research College of Hydraulic and Civil Engineering China Agricultural University Beijing 100083 China 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Yangling 712100 China 3. Geographic and Resources Management college Yantai Normal University Yantai 264025 China

The soil infiltrability of hill-slope is important to such studies andpractices as hydrological process, crop water supply, irrigation practices, and soil erosion. A newmethod for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-outwas advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimatedfrom the advances of runoff on soil surface and the water running out of the slope were *** of 2.cases were conducted. Case Ⅰ was done under a rainfall intensity of 2. mm/h, at aslope gradient of about 0° with a runoff/on length (area) ratio of 1 : 1. Case Ⅱ was under arainfall intensity of 60 mm/h and a slope of 2.° with a runoff/on length (area) ratio of 1 : *** ring method was also used to measure the infiltrability for comparison purposes. Theexperiments were done with soil moisture of 10%. Required data were collected from laboratoryexperiments. The infiltrability curves were computed from the experimental data. The resultsindicate that the method can well conceptually represent the transient infiltrability process, withcapability to simulate the very high initial soil infiltrability. The rationalities of the methodand the models were validated. The errors of the method for the two cases were 1.82./1.39% and4.49%/3.52.% (Experimental/Model) respectively, as estimated by comparing the rainfall amount withthe infiltrated volume, to demonstrate the accuracy of the method. The transient and steadyinfiltrability measured with double ring was much lower than those with this new method, due towater supply limit and soil aggregates breaking down at initial infiltration stage. The method canovercome the short backs of the traditional sprinkler method and double ring method for soilinfil-traility. It can be used to measure the infiltrability of sloped surface underrainfall-runoff-erosion conditions, in the related studies.

关键词： Infiltrability, runoff-on-out, rainfall, sloped surface, model.

Determination of 2. β_2.agonists and 5 β-blockers in animal muscle by high performance liquid chromatography-linear ion trap mass spectrometry

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Science china Chemistry 2010年第4期53卷 832-840页

作者： WU YongNing1,2. MIAO Hong1, FAN Sai1,2.& ZHAO YunFeng1,2.1 Institute of Nutrition and Food Safety, Chinese Centre for Disease Control and Prevention, beijing 10002., china {2. of Veterinary Medicine, china agricultural university, beijing 100193, china 1. Institute of Nutrition and Food Safety Chinese Centre for Disease Control and Prevention Beijing 100021 China2. College of Veterinary Medicine China Agricultural University Beijing 100193 China

A high performance liquid chromatography-linear ion trap mass spectrometry method using isotope dilution technique has been developed for the simultaneous determination of 2. β2.agonists and 5 β-blockers in animal muscle tissues. Pork and chicken muscle samples were acid hydrolyzed and extracted with 5% trichloracetic acid in water, and then cleaned up using MCX solid phase extraction (SPE) cartridge. Methanol and 0.1% formic acid were used as mobile phases for gradient elution. A waters AtlantisT3 column was used for separation. ESI positive ion scan mode was used with selective reaction monitoring. 9 β2.Agonists labeled by the deuterium isotope were used as internal standards for quantification. The linear ranges of 2. β2.agonists and 5 β-blockers were 5-2.0 μg/L, the coefficient of correlation was not less than 0.995, and the limit of detection for each compound in the muscle tissue was below 0.2.μg/kg. The recoveries of each compound in the spiked samples at three levels 5, 10, 2. μg/kg were in the range of 47.3%-12..7%, and the relative standard deviations were in the range of 3.2.-2..7%. The developed method is sensitive and specific for the determination of β2.agonists and β-blockers in pork and chicken muscle samples.

关键词： β2.agonists β-blockers muscle determination HPLC-ITMS

Molecular Cloning of a Cytosolic G6PDH Gene from Populus Suaveolens and Its Expression to Improve the Cold Resistance of Tobacco Plants

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冰川冻土 2009年第6期31卷 1178-1185页

作者： LIN Yuan-zhen1,2.GUO Hai3,ZHANG Zhi-yi2.LIN Shan-zhi2.(1. college of Forestry,South china agricultural university,Guangzhou Guangdong 510642.{2. 2. Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants,MOE,beijing Forestry university,beijing 100083,{2. 3. Plant Materials Center for Soil and water Conservation,Ministry of water Resources,beijing100038,{2.) college of Forestry South China Agricultural University Guangdong Guangzhou 510642 Plant Materials Center for Soil and water Conservation Ministry of Water ResourcesChina Beijing 100038 beijing Forestry university Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental PlantsMOE Beijing 100083 beijing Forestry university Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental PlantsMOE Beijing 100083

Glucose-6-phosphate dehydrogenase (G6PDH,EC 1.***.1.49) is the first and main regulated enzyme of oxidative pentose phosphate pathway (OPPP),catalyzing the conversion of glucose-6-phosphate to 6-phospho-gluconolactone and playing important roles in the growth and development of plants. It is preciously reported that the enhancement of freezing resistance of Populus suaveolenscuttings is clear related to the distinct increase in cytosolic G6PDH activity. Here,a 1697 bp cDNA fragment (PsG6PDH) is amplified by RT-PCR from cold-induced total RNA of the freezing-tolerant P. suaveolens. A sequence analysis showed that PsG6PDH coding region had 1 530 bp and encoded 510 predicted amino acid residues. Genomic Southern analysis revealed that the isoform is encoded by a few copies of the gene in the poplar genome. The cloned gene PsG6PDHis cloned into binary vector pBI12. and used to transform tobacco. PCR and Southern blotting results verified integration of this gene into the genome of tobacco. Moreover,cold treatment experiments and membrane defense enzymeactivity analysis confirmed that overexpression of the PsG6PDHgene could enhance the tolerance to cold or frigid stresses in transgenic plants.

关键词： Populus suaveolens glucose-6-phosphate dehydrogenase cold resistance gene engineering