Airlift Used to Dredging in the ThreeGorges Reservoir-Region

The method using the airlift assisted with the self oscillation pulsed jet for dredging in the Three Gorges Reservoir Region has been presented. The physical and mathematical model of airlift has been given. The feasibility of the self oscillation pulsed jet as breaker of the airlift is researched. It is theoretically and experimentally shown that the self oscillation pulsed jet not only crushes and looses mud deposit under water, but also lifts particles of solid on the clay and sand or mud bed. The oscillation cross flow caused by the self excited oscillation jet makes particles of solid enter the end of the suction pipe easily.     

Experiments of the Self-excited Oscillation Pulsed Jet Nozzle

The self-excited oscillation pulsed jet nozzle which proposed makes the continuous jet transform into pulsed jet . Comparing with general continuous jet, the pulsed jet has a higher peak of pressure and larger volume of erosion , therefore it increases the effective distance off of the jet under the same conditions. The laboratory and industry experiments of the Self-excited oscillation pulsed jet nozzle are introduced in the report.     

Effects of Wave Speed on Frequencies of the Self excited Oscillation Pulsed Abrasive Water Jets

The effects of cavitation and abrasive acceleration in the self excited oscillation pulsed abrasive water jets are directly determined by its oscillating frequencies, so the wave speed in the jets and its effects on pulsed frequencies are discussed. The numerical results show that the oscillating frequencies of the jets increase obviously with decreasing wave speed, and the abrasive parameters have almost no effects on the wave speed, whereas the exit of air in fluid has significant consequences on the wave speed.It was found that these conclusions were applicable for design the nozzle of the jets.     

Mechanism of Self-excited Oscillation Pulsed Jet Aerator

Based on the theory of boundary layer theory and vortex theory of fluid mechanics, a self-suction self-excited oscillation pulsed jet aerator is introduced . This new type of jet aerator adopts self-excited oscillation cavity to replace the traditional mixing tube, and forces air and oxygen-demand water to intermix, compound and oxygenize violently in the cavity under the effect of self-excited oscillation, eject through the special shaped tail tube in the pulsed mode. Theoretical analysis and preliminary industrial experiments show that the new type of jet aerator has an excellent effect of intermixing, compounding and aerating, and that the oxygen-demand water ejected through the special shaped tail tube has an intensive pulsation effect.     

Self-exited Oscillation Vortex Chamber Watering Device

A new type of watering device ,self exited oscillation vortex chamber watering device, is put forward.The jet is controlled by a circular vortex chamber,and self exited oscillation occurs due to a pressure difference between the left and right parts of vortex chamber. By the momentum balance of jet and the masses of air flowing into or out the chamber though air hole,the critical pressure and the time required for reaching the critical pressure can be calculated. This watering device has appropriate size of water drops and uniform water distribution.     

Numerical simulation and on-site test of anincreasing pipe gas delivery capacity device

The theoretical analysis and experiment show that the wall oscillation can reduce the friction drag of the pipe. The operation mechanism, on-site test and numerical simulation of the Increasing Gas Delivery Capacity Device for the Pipe (IGDCDP) invented by the author are introduced in the paper. The on-site test shows that the IGDCDP can not only reduce the friction drag, but also enhance the gas delivery capacity obviously in the natural gas network. The numerical simulation results show that at the time of inducing some new vortex disturbance waves, the pressure pulse wave generated from the impinging edge has an effect on the oscillation cavity wall to cause oscillation with the large structured vortex rings, so the oscillation cavity is the main component that generating the pulsed jet.     

EXRERIMENTAL STUDY OF THE PULSED WATER-GAS JET

A new pulsed jet device is presented which can produce oscillatory pulsed wafergas jet. This device is used in the erasive experiment on the while sandbrick whose compressive resistance is 30 Mpa. The curves of the erasive effects of the oscillatory pulsed water-gas jet.the oscillatory pulsed jet and the ordinary jet are drawn in order to be compared.which are changed as the distances of the targets are changed. In addition the reason why the erasive effect of the new jet is superior to the other two jets is analyzed.     

THE EROSION STUDY OF THE SELF-EXCITED OSCILLATION CAVITATION JET

Based on references [1, 2, 3], we designed a set of device of the self-excited oscillation cavitating jet. Its cavitation mechanism and the result of jet impact block are analysed. With erosive volume as the object, the effect of the self-excited oscillation cavitating jet is compared with that of conventional continuous jet under the same condition. It is found cxperimeetally that the position of suction air and the air quantities and the geometrical parameters of the device have great effect on the erosive effects of the self-excited oscillation cavitating jet. In certain range of stand off distance, it's not obvious that the erosive effects of the self-excited oscillation cavitating jet changed with stand off distance for pulse cavitating jet and cavitation bubblies and droplet impinging on the target. Compared with continuous jet, the erosive vo-l ume and area of the self-excited oscillation cavitating jet is more than one time larger than the continuous jet.     

Analysis on stress wave effect during the process ofrock breaking by pulsed jet

A mathematical model of rock breaking under pulsed jet is established by introducing the Johnson-Holmquist-Concrete constitutive relation and the smoothed particle hydrodynamics method. Based on this model, the formation, propagation and attenuation of stress wave during rock breaking by pulsed jet are simulated. The relations between pressure and time at different points on rock surface and the curve of peak stress wave versus distance to action spot are obtained. Destruction behaviors of rock under pulsed jet and effects on stress wave effect from jet velocity and lithology are studied according to the above calculation results, analysis results show that stress wave effect of pulsed jet acts locally and the peak stress wave shrinks sharply as the acting distance increases. The rock breaking mechanism of stress wave is tensile failure during the high speed process of load-unload. Power and effect range of stress wave is in high direct proportion with jet velocity. There is a threshold velocity before the macroscopic failure. Rocks of different lithologies have different destruction types under pulsed stress wave of pulsed jet. Destruction type of low strength rock like sandstone is crack propagation under the tensile stress during the high speed process of load-unload, while the destruction type of high strength brittle rocks like granite and limestone is vertical failure of stress concentration.     

Ice Jet and Ice Preparation

An injection ice jet system has been studied and established.Through ice jet removing paint experiment,three parameters that influence removing efficiency such as flow,temperature,diameter are investigated.The experiment results come to the conclusion that ice jet can achieve removing paint in lower working pressure.Also a plan of preparing ice particles continuously has been put forward,and the analyses and calculations are done in terms of theory.     

Research of Application About Environment Dredging on River and Reservoir with Water Jet Airlift

Being established in the thought of environment dredging, the crafts flow of water jet airlift dredging and treating of surplus water as well as circle using of mud polluted have been analysed following the status in quo of pollution of the fiver and reservoir. Definitely, it has been pointed out that the total of mud will be reduced with the technique of dehydration so as to reduce the volume of mud stack. At the same ring the surplus water. The mud which had been treated can be time, it will be reduced for pollution secondly by treaused as soil of fiver or gardens or road for the recycle. Then, the parameter and efficiency of production in HuaXi river valley integration treating project have been expatiated particularly in environment dredging. It indicates the new way for environment dredging in river and reservoir at the mountainous area.     

Effect of Main Parameters on Cutting of the Pulsed Abrasive Water Jet

The relationship between abrasive concentration, length of oscillating chamber, standoff distance and cutting depth, erosion rate as well as cutting specific energy was investigated by experiments in the submerge and surface conditions. The cutting and erosion capabilities of the pre-mixed abrasive water jet and the pulsed abrasive water jet were analyzed in contrast. It is shown that the maximum cutting depth and erosion rate of the pulsed abrasive water jet are respectively 1.67,1.72 and 1.39, 1.47 than the pre-mixed abrasive water jet in submerge and surface conditions. These results attained from the research are useful to increase the cutting efficiency, decrease the energy ratio and expand the application domains of the abrasive water jet.     

Effect of Deflection Characters on Self oscillating Water Jet

The deflective mechanism of the oscillating water jet is analyzed and the effects of jet deflection on the self oscillating water jet are investigated. It is experimentally shown that the deflective angle may reach 9.53 degree, the pressure fluctuation is more intensive and more regular and the jet can efficiently eliminate the water cushion effect and increase the ability in cutting.     

Studies on Dust-Laying with Swirl-Water Jet

The main optimum parameters of laying dust for mine is introduced in this pa-per.The related parameters of laying dust with swirl,pulsed and ordinary water jet are analysed re-spectively at different water pressures.     

丹参毛状根生物反应器大规模培养的研究

以总丹参酮(脂溶性成分)的含量为监测对象,利用10L的球状气升式反应器进行了丹参毛状根培养的初级放大试验,发现球状气升式反应器培养50d时丹参毛状根的增殖倍数为241．71倍,高于三角瓶摇瓶培养的丹参毛状根的增殖倍数,其总丹参酮的含量接近三角瓶摇瓶培养的丹参毛状根总丹参酮的含量。接着,以原儿茶醛和丹酚酸B这两种水溶性成分为监测对象,利用75L的气升式反应器进行了进一步的放大培养,发现它们的含量在75L的气升式反应器培养50d时所获得的丹参毛状根中与10L的球状气升式反应器培养50d时所获得的丹参毛状根中相当。这些结果表明,利用气升式反应器进行丹参毛状根初级放大和中试规模的培养是可行的,它为今后丹参毛状根的工业化生产奠定了基础,有望为象丹参这样的名贵植物资源的持续开发与利用以及绿色原料药的生产开辟一条新途径。     

Mechanism analysis of permeability based on promoting coal matrix shrinkage by water jet

High pressure pulsed water jet (HPWJ) is a new technology of effectively improving coal seam permeability. However, the mechanism of increased permeability is not yet clear, which restricts the application of HPWJ in different coal seams. From the perspective of improving permeability by coal matrix shrinkage, the impelled dynamic equations is established based on analysis of coal dynamic effects by water jet. According to theoretical analysis of the stress state of coal matrix, it is concluded that HPWJ can promote coal matrix shrinkage, and the relationship equation between jet impact-coal matrix is derived. Besides, the gas seepage function in the coal slotted by the HPWJ is gained by using PM model, which provides theoretical support for generalizing the technology in the coal mine.     

Effect of Vanadium Content on VC Precipitation in PD3 Steel

In order to identify the affect of vanadium in pearlite transformation and the regularity of the precipitation, the effect of vanadium content on VC precipitation in PD3 steel has been studied by electrochemical extraction and TEM. The results show that the solid solubility limit of vanadium in the ferrite and Fe 3C is 0.09% and 0.23% respectively, that vanadium exist mainly as solid solution and a few VC particles are precipitated in disordered way in case of the vanadium content being below 0.21%, that VC particles are precipitated in excess of saturated solubility, and that a lot of VC particles are precipitated in disordered and "interphase precipitated" way in case of the vanadium content being above 0.21% and arrive at 0.33%.     

Numerical analysis on sparse solid particles’ motion in flow fields of different density

The three dimensional numerical solution for differential equation of motion of sparse solid particles in flow fields is derived. Taking free sedimentation of solid particles as an example, using dimensionless differential equation, the movement rule of solid particles in water and air is numerically analyzed. The contribution of Basset force on solid particles in different density flow fields is paid much attention to. The results show that the Basset force and drag force are in the same magnitude when solid particles move in water; the effect of Basset force can be neglected when solid particles move in the air; and the Basset force should be considered when river water source heat pump and the flow of silt particles are studied.     

盐酸浸提-AAS法测定植物钾、钙、镁含量的检测条件优化与改进

为了优化盐酸浸提-AAS法的检测条件,在植物颗粒不同粒径、振荡不同时间、浸提不同温度、浸提不同方式及不同浓度盐酸浸提条件下,以盐酸浸提法测定钾、钙、镁含量。结果表明,盐酸浸提法适宜采用过60目筛的植物颗粒,以室温盐酸浸提,适宜振荡时间为90min。以热盐酸浸提,适宜采用55℃热盐酸振荡60min,盐酸适宜浓度为1mol/L,盐酸浸提样品的适宜方式为振荡。本实验提出的盐酸浸提-AAS方法准确高效,经济安全,操作方便,适用于批量样品的检测分析。     

Theoretically Investigation of Dynamic Characteristics of Spherical Bubble Collapse in Pulsed Abrasive Water Jet

This paper theoretically investigates the characteristics of cavitating bubbles in the pulsed abrasive water jet(PAWJ) and establishes the dynamic equations of cavitating bubbles. The effects of abrasive diameter and density on the spherical bubble collapse are also analyzed. It is found that the change of abrasive diameter rarely affects the bubble collapse when the abrasive diameter and density are small whereas the smaller abrasive greatly blocks the bubble collapse when the abrasive diameter and density are comparably big. It is also shown that when the abrasive density is increased, the fluid viscosity rises, and the kinetic energy of the abrasives near the collapsed bubble is enhanced and meanwhile the intensity of cavitating erosion is weakened.