水反应金属燃料发动机初步试验

介绍了水反应金属燃料发动机试验系统,提出了水燃比、工作压强及试验燃烧效率计算方法,为试验设计和发动机性能评价提供了依据。对水反应金属燃料发动机进行了试验研究,并根据试验结果对药柱组分、发动机结构及供水系统进行了改进。试验表明,中等含量金属燃料加水后可稳定燃烧,通过增加燃料中镁含量、稳定进水流量和增加补燃室长度等措施,可有效提高发动机燃烧效率。

Removal of PCDDs/Fs from municipal solid waste incineration by entrained-flow adsorption technology

Entrained flow adsorption using activated carbon as the adsorbent is widely adopted for PCDDs/Fs-abatement in municipal solid waste incineration (MSWI) process. The effects of operating parameters including flue gas temperature, feeding rate of activated carbon, polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs) concentration at the inlet of the air pollution control device (APCD), filter materials, pressure drop on PCDDs/Fs removal efficiency are reviewed and commented upon in this paper. Evaluation on the various mechanistic models for entrained flow adsorption is carried out based on the computational simulation in terms of the actual operating condition and theoretical analysis. Finally, an advancement of en- trained flow adsorption in combination of dual bag filter is introduced.

Effects of working parameters on gasoline engine exergy balance

To improve the energy utilization efficiency of internal combustion （IC） engine, exergy analysis was conducted on a passenger car gasoline engine. According to the thermodynamic theory of IC engine, in-cylinder exergy balance model was built. The working processes of gasoline engine were simulated by using the GT-power. In this way, the required parameters were calculated and then gasoline engine exergy balance was obtained by programming on computer. On this basis, the influences of various parameters on exergy balance were analyzed. Results show that, the proportions of various forms of exergy in gasoline engine from high to low are irreversible loss, effective work, exhaust gas exergy and heat transfer exergy. Effective exergy proportion fluctuates with cylinder volumetric efficiency at full load, while it always increases with break mean effective pressure （BMEP） at part load. Exhaust gas exergy proportion is more sensitive to speed, and it increases with speed increasing except at the highest speed. The lower proportion of heat transfer exergy appears at high speed and high load. Irreversible loss is mainly influenced by load. At part load, higher BMEP results in lower proportion of irreversible loss; at full load, the proportion of irreversible loss changes little except at the highest speed.

Effect of working parameters on performance characteristics of hydrostatic turntable by using FSI-thermal model

Effects of working parameters on performance characteristics of hydrostatic turntable are researched by applying the fluid-structure-thermal coupled model.Fluid-structure interaction(FSI)technique and computational fluid dynamics(CFD)method are both employed by this new model,and thermal effects are also considered.Hydrostatic turntable systems with a series of oil supply pressures,various oil recess depth and several surface roughness parameters are studied.Performance parameters,such as turntable displacement,system flow rate,temperature rise of lubrication,stiffness and damping coefficients,are derived from different working parameters(rotational speed of turntable and exerted external load)of the hydrostatic turntable.Numerical results obtained from this FSI-thermal model are presented and discussed,and theoretical predictions are in good agreement with the experimental data.Therefore,this developed model is a very useful tool for studying hydrostatic turntables.The calculation results show that in order to obtain better performance,a rational selection of the design parameters is essential.

Experiment and Simulation of Large Capacity Air-guns in Deep Structure Exploration

The air-gun source has important applications as a new, environmentally, green active source in regional scale deep exploration. In the past, the air gun source was used mainly in smallscale, high-resolution shallow oil exploration, but has a lack of adequate research in deep exploration. In order to study the selection of work parameters and field conditions of the air gun source in deep exploration, this paper does the following work： （1） analyze the characteristics of the air gun source using air gun experiments; （2） simulate the air gun signal and air gun-array signal based on the theory of free bubble oscillation to analyze the influence of bubble oscillation and study the wavelet energy and spectrum characteristics needed in deep exploration; （3） on the basis of theoretical simulation, study the influence of work parameters, such as air-gun capacity, work stress and depth on air gun signal and analyze the influence of air-gun array inspired moment and spacing of different air guns on air gun-array signals; and （4） study energy reflection and transmission coefficients for different underwater interfaces, which is very useful for choosing suitable field conditions.

Air flow calculation of reverse circulation drilling technique with air DTH hammer

Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas. In order to expand the applications of the technology,the authors further studied the principle and analyzed the mechanism of reverse circulation drilling technique with air DTH hammer to get the perfect assembles of equipments by optimizing working parameters. No parameter seemed more important than the air volume because it could maintain the working performance stability. The minimum air volume is related to the parameters such as depth and pressure,which was calculated under the actual conditions. It was solved for the air injection flow tables of the air DTH Hammer working at the different pressures. According to the data tables,operators could adjust the air volume to meet the demand on this technique,which had a realistic guiding significance. So it could build up a set of systematic and complete hi-technique.

Ventilation control of tunnel drilling dust based on numerical simulation

In order to control the dust pollution produced by air leg rock drill in the trolley area during the excavation of long-distance single ended tunnel,the full-scale physical model of working face was established by using FLUENT software,and the numerical simulation analysis of tunnel drilling ventilation and dust removal parameters was carried out.The results show that it is difficult to control the dust pollution of the face by conventional ventilation,and the drilling dust is distributed in the range of 10 m from the face;after the introduction of the long pressure and short suction ventilation scheme,when the ratio of compressed air volume to exhaust air volume is 0.72,the height of the pressure fan is 2.5 m,the distance between the pressure fan and the palm face is 20 m,and the exhaust fan is 12 m away from the palm,the dust concentration control efficiency of the working face is increased by about 60%.Therefore,in the similar long-distance single head tunnel construction,it is appropriate to adopt the dust removal method of long-distance short suction and exhaust fan to ensure the working environment.

Parametric analysis of mixed lubrication characteristics in work zone of strip rolling

A theoretical model for mixed lubrication with more accurate contact length has been developed based on the average volume flow model and asperity flattening model,and the lubricant volume flow rate and outlet speed ratio are determined by integrating differential equations based on rolling parameters.The lubrication characteristics at the roll-strip interface with different surface roughness,rolling speed,reduction and lubricant viscosity are analyzed respectively.Additionally,the average volume flow rates of lubricant under different rolling conditions are calculated and used to explain the change rule of lubrication characteristics.The developed scheme is able to determine the total pressure,lubricant pressure,film thickness and real contact area at any point within the work zone.The prediction and analysis of mixed lubrication characteristics at the interface is meaningful to better control the surface quality and optimize the rolling process.

Study on the all position automatic pipeline backing weld machine

As a result of the lower backing weld efficiency, the applying of automatic welding is seriously limited. So a kind of special automatic welder is designed and manufactured for backing weld. This paper introduces the character of the assembled pulse CO2 arc welding machine which has strong penetrability. It specifies the technology of controlling the parameters of all position automatic welding by computer and multi-axis controller. Moreover typical welding procedure parameters are provided. It is proved by examination that the economical and practical equipment and technology are suitable for the long-distance transmission pipeline, and it has a good foreground of spreading and applying.

Reducing residual distortion of thin-plate weldments by rotating extrusion

A new method named rotating extrusion was developed to mitigate residual distortion of thin-plate weldments. The basic principle and characteristic of rotating extrusion as well as an efficient rotating extrusion device were introduced. Systematic trials were conducted to investigate the influence of several technological parameters including the distance between the extrusion tool and welding torch, the pressure acting on weldment, the dimension of the extrusion tool and its rotational speed on distortion control effect. Experimental results show that, as for 2A12T4 aluminum alloy weldment with 2 mm in thickness, 150 mm in width and 350 mm in length, when appropriate technological parameters are adopted, rotating extrusion can reduce its buckling deflection to below 3% of the original value. Implementing rotating extrusion during welding with an extrusion tool more than 100 mm away from the welding torch may achieve better distortion mitigation effect.

Technical parameters of drawing and coal-gangue field movements of a fully mechanized large mining height top coal caving working face

Under fully mechanized, large mining height top coal caving conditions, the shield beam slope angle of the support increases due to the enlargement of the top coal breaking and caving space. This results in a change of the caving window location and dimensions and, therefore, the granular coal-gangue movement and flows provide new characteristics during top coal caving. The main inferences we draw are as follows. Firstly, after shifting the supports, the caved top coal layer line and the coal gangue boundary line become steeper and are clearly larger than those under common mining heights. Secondly, during the top coal caving procedure, the speed of the coal-gangue flow increases and at the same drawing interval, the distance between the coal-gangue boundary line and the top beam end is reduced. Thirdly, affected by the drawing ratio, the slope angle of the shield beam and the dimensions of the caving window, it is easy to mix the gangue. A rational drawing interval will cause the coal-gangue boundary line to be slightly behind the down tail boom lower boundary. This rational drawing interval under conditions of large mining heights has been analyzed and determined.

Optimizing Geothermal Energy Resource

Unlike other types of renewable energy resources, geothermal energy provides a stable source of energy as it can be exploited regardless of meteorological conditions. Using organic cycle, geothermal energy can be utilized for power generation. In such systems, the heat is exchanged between the surrounding rock mass and transport fluid. Consequently, the temperature of extracted geofluid from the well decreases with the time in accordance with the working parameters. Those parameters includeenergy extraction rate, temperature difference between inlet and outlet of the well, and the thermal conductivity of the ground. Current work, aims to develop a reliable computer model to specify the optimal working parameters so that the geofluid temperature will not reach a low value that is not acceptable for electricity generation, and the energy availability of geothermal resource is maximized. In the current study the ground thermal properties, the geothermal gradient and well dimensions are based on realistic data in Qatar and neighboring countries. The proposed model was developed for different heat extraction rate, different ground thermal properties, and for varied temperature difference between inlet and outlet of the well. Simulation shows that selecting the optimal working parameters can increase the availability of geothermal resource significantly.

ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS

The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount Δτ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount Δτ13 where Δτ13 is the product k and ten-sioned load p, i. e. Δτ13 = kp, where k is a function of two variables x and y. The distribu-tive properties both Δτ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.

Electromagnetic drive system of robotic fish

With the aim to apply the electric fish into practice to assist coal mine water disaster life detection and rescue work, based on the analysis on swing propulsion movements of tail fin, this paper integrates the electromagnet technology with tail fin drive system by analyzing how the fish swims with tail fin under the law of progression. The principle, structure, and drive signals of tail fin electromagnetic drive are researched, the enforced situation of fish under eIectromagnetic driving modes are analyzed, and the experimental plat-form of tail fin electromagnetic drive is established. The best distance between electro- magnet and armature, which can realize the swing of tail fin, was researched in the experiment under water. The robotic fish structure parameters of tail fin electromagnetic drive was finalized by theoretical analysis and experimental measurement.

THE THEORETICAL MODEL FOR PREDICTING CIRCULATION VELOCITY OF HYDRAULIC BRAKE

By rational hypothesis of fluid flow pattern, applied the law of conservation of energy and integrated the laboratory test results, finished the prediction by the theoretical model of cir-culation velocity of hydraulic brake which is important parameter. Thus provide the theoritical basis for hydraulic brake of bblt conveyor whose research has just been started.

Effect of Soil Strength and Soil Physical Properties on Performance of Tillage Machines

Soil parameters have significant influence on the performance of tillage machines for various kinds of tillage operations, such as soil movement by tillage tool, soil cutting, soil turning, soil pulverization, and manure injections, etc. This paper attempts to provide a clear overview of soil physical properties and soil strength, and their effects on the performance of tillage machines. Furthermore; it includes the descriptions and characteristics of these parameters, and last developed equipment and procedure for evaluating and assessing of these parameters.

Mobility and constant-orientation workspace analysis of 4UPS-UPU parallel mechanism

One of the key issues for parallel mechanism is the kinematic characteristics,especially the workspace which varies with configuration parameters.A kind of 4UPS-UPU parallel mechanism is designed and its workspace is studied in this paper.First,the mobility of the 4UPS-UPU parallel mechanism is analyzed based on the reciprocal screw theory,and the motion and constraint screw systems of the parallel mechanism are obtained.Then the inverse kinematics is derived by the closed-form kinematics chain.The boundary search method in the polar coordinate system is presented to analyze the constant-orientation workspace of the parallel mechanism.Finally,the influence factors relevant to the workspace,such as the structural parameters and kinematics parameters are analyzed in detail.The relationship between the workspace volume and different parameters are obtained.The conclusions can be used for parameters optimization and path planning of the parallel mechanism.

Investigation of different coal types effect on the overall plant recovery

Coal washing plants are usually fed from various sources. Coals include different combinations which should be considered for increasing the plant proficiency. Thus different methods have been used to enrich various coal types. In this study, Alborz-Sharghi coal washing plant was investigated which is fed from five coalmines. The optimum recovery was achieved for all coal types individually through experimental design. The controllable operation parameters in the experiments were collector dosage,frother dosage, solid percent content and particle size. The other parameters such as impeller speed,pH, conditioning time and flotation time were kept constant for all experiments. The optimum combination of coals was also specified. The results show that the optimum recovery for coal blends is 91.2%which shows much improvement relative to the plant conditions.

A Brief Introduction to the Seismotectonic Map of Xinjiang and Its Neighborhood

This paper briefly introduces the Seismotectonic Map of Xinjiang and its neighborhood in the scale of 1∶2500000.The map is amended,supplemented and expanded based of the newly compiled Seismotectonic Map of Xinjiang in scale 1∶1000000.The base map of this seismotectonic map is the geologic map of western China and its neighborhood compiled by Li Tingdong.The abundant new materials from related research,referential literatures and the analyses on remote sensing data were used in the compiling work.A database and relevant documents are built for nearly 300 active faults and 150 active folds.The basic information of the major active faults,especially those near the border areas in this map are introduced in this paper.

Construction of Micropiles Using Pressure Techniques

This paper discusses the technique of casting concrete ofmicropiles with pressures and the consequence of comparisons with normal way of casting concrete （casting with gravity）. Preliminary geotechnical studies have been made in specific area in Sudan to predict the soil parameters and then an experimental work has been done for an estimated number ofmicropiles with different diameters and different techniques of placing concrete with various amount of pressure. This study was carried out to learn the usefulness of this technique in the field of structural foundations in Sudan. Capacities of micropiles were compared in cases of non-pressure casting （normal way of casting concrete） and pressure casting. Through the results, it was found that the entry of pressure factor in the operation of casting concrete increases the capacities of micropiles. The increased value of ultimate load depends on the amount of pressure applied.