HYDRODYNAMICS STABILITY OF BICKLEY JET WITH PARTICLE LADEN FLOW

The stability of Bickley jet with particle laden flow is investigated numerically. The stability characteristics are calculated for various Stokes numbers and particle concentrations. The results confirm the author's early calculations, which also shows that the numerical program is reliable. It is further shown that there is a critical value for the effect of Stokes number, which is about 2. The most damped mode occurs when Stokes number is of order of 10 for different particle concentrations and depends weakly on the wave number. The difference in the eigenfunctions and its derivatives between the particle-laden flow and the clean gas flow is insignificant for fine particles, while the difference for coarse particles is significant.     

AERATION EFFECT OF SUBMERGED JET ON HYDRAULIC CHARACTERISTICS

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＪｅｔｆｌｏｗｈａｓｂｅｅｎｅｘｔｅｎｓｉｖｅｌｙａｐｐｌｉｅｄｆｏｒｅｎｅｒｇｙｄｉｓｓｉｐａｔｉｏｎ .Ｉｎｄｅｓｉｇｎ ,ｈｏｗｅｖｅｒ,ｂｅｃａｕｓｅｏｆｔｈｅｃｏｍ ｐｌｅｘｉｔｙｏｆｐｒｏｂｌｅｍａｎｄｔｈｅｄｉｆｆｉｃ     

PDA MEASUREMENTS OF TWO-PHASE FLOW STRUCTURE AND PARTICLE DISPERSION FOR A PARTICLE-LADEN JET IN CROSSFLOW

The two-phase flow structure and particle dispersion for a dilute particle-laden jet in crossflow(JICF) were experimentally investigated by means of Phase Doppler Anemometry(PDA) measurement.The two-phase flow experiments were conducted for different flow conditions and solid particle parameters,including the ratio of the jet velocity to crossflow velocity,the particle size and mass loading.The experimental results indicate that the fine particles with the size of 70 micron and the mass loading of 0.05% hav...     

SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the verification of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.     

SCALE EFFECT OF IMPINGING PRESSURE CAUSED BY SUBMERGED JET

The characteristics of the impinging pressure at the jet equipment where the maximum jet velocity can reach 50m/s were studied. By comparing the impinging pressure with the one measured at the low velocity conditions, two conclusions of the scale effect are drawn： firstly, the velocity attenuation degree is smaller than that of low velocity jet, and secondly, the relative impinging width is narrower than that of low-velocity jet. The reasons of the scale effect of the impinging pressure were elucidated through numerical simulation.     

A STUDY ON THE FLOW BEHAVIOR OF AN AXISYMMETRIC LAMINAR JET

It is of great practical and theoretical importance to study the properties and flowbehavior of laminar jet,because it tightly links the physical phenomena of nonlinerity such asflow stability and transition and so forth.However,many problems and differences exist in ba-sic concepts and in understanding of stable and transitional properties and flow patterns of ax-isymmetric laminar jet.Therefore,a further study on this subject is needed to evaluate the exist-ing understandings and to find out the mechanism governing the behavior of actual axisymmetriclaminar jet flow.In this thesis,the flow behavior of axisymmetric laminar jet issuing from nozzles of severaldiameters in the direction of gravity was studied experimentally using flow visualization tech-nique in the range of Reynolds number from tens to thousands.The unstable and transitionalprocesses in the laminar jet were observed.The influence on the jet flow of different geometrycontours of jet chamber boundary was investigated.Some new flow phenomena were discoveredwhich gave deeper understanding of flow patterns and their dependent factors in low Reynoldsnumber axisymmetric laminar jet.A theoretical model to describe the variation of the axisym-metric laminar jet length influenced by the weak density difference is proposed based on the ex-perimental observation,which will be helpful in recognizing the flow behavior of axisymmetriclaminar jet of low Reynolds numbers.     

EFFECT OF SURFACTANT ON TWO-PHASE FLOW PATTERNS OF WATER-GAS IN CAPILLARY TUBES

Flow patterns of liquid-gas two-phase flow were experimentally investigated. The experiments were carried out in both vertical and horizontal capillary tubes having inner diameters of 1.60 mm. The working liquid was the mixture of water and Sodium Dodecyl Benzoyl Sulfate (SDBS). The working gas was Nitrogen. For the water/SDBS mixture-gas flow in the vertical capillary tube, flow-pattern transitions occurred at lower flow velocities than those for the water-gas flow in the same tube. For the water/SDBS mixture-gas flow in the horizontal capillary tube, surface tension had little effect on the bubbly-intermittent transition and had only slight effect on the plug-slug and slug-annular transitions. However, surface tension had significant effect on the wavy stratified flow regime. The wavy stratified flow regime of water/SDBS mixture-gas flow expanded compared with that of water-gas.     

EFFECT OF ENLARGED FREE JET ON ENERGY CONVERSION IN PELTON TURBINE

NOMENCLATURE Q —flow rate H— head Dref —diameter of pitch circle B —inner width of bucket ω —angular speed of runner QDH —unit discharge Sn —needle strokesn—relative needle stroke Dinj —diameter of injector inlet Dt —diameter of nozzle throat D     

基于扬压力实测资料的古田溪四级大坝稳定分析

针对古田溪四级大坝部分坝段坝基扬压力较大的问题，应用坝基总扬压力模型和概率法对坝基扬压力性态和可能极值进行了分析，由此进一步分析了典型坝段的稳定状况。     

STUDIES OF SOLID－LIQUID TWO－PHASE TURBULENT FLOWS AND WEAR IN HYDRAULIC TURBOMACHINERY

ＳＴＵＤＩＥＳＯＦＳＯＬＩＤ－ＬＩＱＵＩＤＴＷＯ－ＰＨＡＳＥＴＵＲＢＵＬＥＮＴＦＬＯＷＳＡＮＤＷＥＡＲＩＮＨＹＤＲＡＵＬＩＣＴＵＲＢＯＭＡＣＨＩＮＥＲＹ￥ＬｉｕＸｉａｏ－ｂｉｎｇ（ＳｉｃｈｕａｎＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｃｈｅｎｇｄ...     

EFFECT OF A MOVING BOUNDARY ON THE FLUID TRANSIENT FLOW IN LOW PERMEABILITY RESERVOIRS

In a low permeability reservoir, the existence of a moving boundary is considered in the study of the transient porous flow with threshold pressure gradient. The transmission of the moving boundary directly indicates the size of the drainage area as well as the apparent influences on the pressure behavior. The nonlinear transient flow mathematical model in which the threshold pressure gradient and the moving boundary are incorporated is solved by advanced mathematical methods. This paper presents some new analytical solutions describing the pressure distribution at a constant rate and the production decline in a constant pressure production with the boundary propagation. It is shown that the greater the threshold pressure gradient, the slower the transmission of the moving boundary, the larger the pressure loss will be, and there is no radial flow in the middle and later phases of the wellface pressure for a well at a constant rate. We have the the maximum moving boundary at a specific drawdown pressure for a low permeability reservoir. The greater the threshold pressure gradient, the smaller the maximum moving boundary distance, the quicker the production decline for a well in a constant pressure production will be. The type curve charts for the modern well test analysis and the rate transient analysis with a moving boundary are obtained and the field test and the production data are interpreted as examples to illustrate how to use our new results.     

SOLUTION OF RELATIVE PERMEABILITY OF TWO-PHASE FLOW IN POROUS MEDIUM

ＳＯＬＵＴＩＯＮＯＦＲＥＬＡＴＩＶＥＰＥＲＭＥＡＢＩＬＩＴＹＯＦＴＷＯ－ＰＨＡＳＥＦＬＯＷＩＮＰＯＲＯＵＳＭＥＤＩＵＭＬｕＹｕ－ｌｉｎ（ＩｎｓｔｉｔｕｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇ...     

NUMERICAL SIMULATION OF MOVING SCOUR BOUNDARY AND TURBULENCE FLOW AROUND SUBMARINE PIPELINES

A two dimensional vertical mathematical model is proposed in this paper for simulating the equilibrium profile of local scour around submarine pipelines. The current model is composed of a new k-ε turbulence model, fitting moving boundary with pre-meshed grid lines and incipient criterion of shear stress for sediments. Employing the proposed model, an instance is carried out numerically and compared with experiments. The calculation results agree well with the experiments. It shows that the improved two equation turbulence model, adopted in this paper is appropriate to simulating the turbulent flow ficld around submarine pipelines, fitting moving boundary with pre-mcshed grid lines method is efficient for moving boundary problems in a multiply connected domain and the stability evaluation method for seabed with critical shear stress based on log-wall law is a reliable choice.     

EFFECT OF SOLID PARTICLES ON STABILITY FLOW IN THE BOUNDARY LAYER ON A FLAT PLATE

ＥＦＦＥＣＴＯＦＳＯＬＩＤＰＡＲＴＩＣＬＥＳＯＮＳＴＡＢＩＬＩＴＹＦＬＯＷＩＮＴＨＥＢＯＵＮＤＡＲＹＬＡＹＥＲＯＮＡＦＬＡＴＰＬＡＴＥ￥ＬｉｎＪｉａｎ－ｚｈｏｎｇ；ＺｈｏｕＺｅ－ｘｕａｎＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃｓ，ＳｔａｔｅＫｅｙＬａ...     

THEORETICAL AND EXPERIMENTAL STUDY ON THE CONICAL SWIRLING WATER JET FLOW

This paper is concerned with theoretical and experimental study on theconical swirling water jet flow.Based upon the theoretical analysis,the experiment on thestructural characteristics of swirling water jet flow including the velocity and pressure dis-tribution laws,on which the parameters of the jet,nozzle and directional blades havemore or less influence,was carried out in CSSRC by using a 3-D LDV in order to optimizea new high-efficiency jet instead of swirling drilling bit for rock-breaking and continuouslydrilling,and to meet the demand of radial horizontal drilling technology.Meanwhile basedon the experimental results,the numerical simulation was conducted for the conicalswirling water jet in the immersed well-bottom flow by solving the RANS equations in the3-D body-fitted coordinate system with the k-ε turbulence model.The numerical resultsare consistent with the experimental data,and lead to some conclusions which are impor-tant for applying the conical swirling water jet to the petroleum drill     

THE RANDOM ANALYSIS OF APRON SLAB MISSING STABILITY UNDER WATER JET LASHING

ＴＨＥＲＡＮＤＯＭＡＮＡＬＹＳＩＳＯＦＡＰＲＯＮＳＬＡＢＭＩＳＳＩＮＧＳＴＡＢＩＬＩＴＹＵＮＤＥＲＷＡＴＥＲＪＥＴＬＡＳＨＩＮＧ￥ＣｕｌＬｉ；ＺｈａｎｇＴｉｎｇ－ｆａｎｇ；ＬｉＪｉａｎ－ｃｈｕ；ＺｈｏｎｇＢｉｎｇ（Ｄｅｐｔ．ｏｆＣｉｖｉｌＥｎｇｒｇ．...     

NUMERICAL SIMULATION OF 3-D AERATED JET BEHIND FLIP BUCKET OF OVERFLOW DAM

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＪｅｔｆｌｏｗｗｉｄｅｌｙｅｘｉｓｔｓｉｎｅｎｇｉｎｅｅｒｉｎｇ ,ｔｈｅｎｃｅｔｈｅｓｔｕｄｙｏｆｔｈｉｓｋｉｎｄｏｆｆｌｏｗｉｓｖｅｒｙｉｍ ｐｏｒｔａｎｔｉｎｔｈｅｏｒｙａｎｄｐｒａｃｔｉｃｅ ,ａｎｄｍｕｃｈｗｏｒｋｈａｓｂｅｅｎｄｏｎｅｆｏｒｔｈｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓ ,ｎｕｍｅｒｉ ｃａｌｍｏｄｅｌｓａｓｗｅｌｌａｓｔｈｅｃｏｎｔｒｏｌｏｆｔｈｅｊｅｔｆｌｏｗ [1 ] 　 .Ｙｅｔｕｎｔｉｌｎｏｗｍｕｃｈａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｔｏｔｈｅｊｅ…     

EXPERIMENTAL AND THEORETICAL STUDY OF CAVITATION-INDUCED MECHANICAL EFFECT ON A SOLID BOUNDARY

1.INTRODUCTION Theinterestincavitationbubblesinliquids mainlyarosefromtheirdestructiveactiononsolid surfaces,whichwasfirstreportedonshippropel lersinthelastcentury.Ingeneral,cavitationcan beinitiatedbyeithersettingupatensioninaliquid orbydepositingenergyintoit[1,2].Tensionappears influidflows,suchaswithshippropellers,hydro foils,pipesandpumps.Italsooccursinsound fieldsintheunder pressurecycleofsoundwaves,e.g.,inshockwavelithotripsyandsonochemis try.Localdepositionofenergyisbroughtbyheattr…     

ON THE STABILITY OF A LIQUID-FILLED ROTOR

The dynamic stability of a high-spinning liquid-filled rotor with both internal and external damping effects involved in is investigated in this paper. First, in the case of the rotor subjected to a transverse harmonic motion, the dynamic pressure of the liquid acting on the rotor is extracted throuhg a planar flow analysis. Then the equation of perturbed motion for the liquid-filled rotor is derived. The analytical stability criteria as well as the stability boundaries are given. The results are extensions of those given by previous literature.     

RESEARCH ON STABILITY OF OPEN BOTTOM STORAGE PLATFORM

1.INTRODUCTIONBymakingcomprehensivesurveyofallkindsofrecentfloatingstructureinocean,wecandrawtheconclusionthatallthemhaveIIbottomnandbuoyancytofloatonthesea-Inthispaper,wepresentanewtypeofoceanstructurewhichisdifferentfromaconventionalone.Openbottomplatformdiscussedinthispaperconsistsofanupperdeck,fourcolumnswithopenbottomandtrussesconnectinganytwoadjacentcolumns.Everycolumnisahol-1owcylinderwithoutbottom,buthasawater-tightpressurebulkheadinstalledatacertaindistancefromtheopenend.Whenthe…