Visual Basic语言在化学中的应用

对 Visual Basic语言进行简单的介绍 ,并以实例说明其在化学中的应用方法 .可以看出 ,利用 Visual Basic开发化学过程中的数学模拟软件 ,既可以美化软件的界面 ,又可提高程序设计的工作效率 .

CFD prediction of physical field for multi-air channel pulverized coal burner in rotary kiln

A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.

Study on “triangle” water-inrush mode of strong water-guide collapse column

The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological background of Shuangliu mine is considered a prototype, similar simulation tests are adopted to analyze the water-inrush rules under this model, and the formation of water-guide channel and water-inrush process is investigated by examining the changes in rock resistivity. This work also uses the coupled cloud image derived from numerical simulation software to verify the results of simulation test. Results show that the numerical simulation of "triangle" water-inrush mode is consistent with the similar simulation. The "triangle" seepage area, which is located at the bottom of collapse columns and is connected to aquifer, is caused by the altered seepage direction and strengthened seepage actions after the overlapping of hydraulic transverse seepage in collapse column and hydraulic vertical seepage flow in aquifer. Under "triangle"water-inrush model, water-guide channel is formed by the communication between plastic failure zone of working face baseplate and"triangular" seepage area. Accordingly, the threatening water-inrush distance between working face and collapse column increases by 20 m compared with that of theoretical calculation.

Analysis of Static Pressure in Area between Back Plate and Cylinder of a Carding Machine with CFD

To analyze static pressure between back plate and cylinder in an A186 carding machine,a fluid model is established. The model takes into account static pressure of airflow near back plate with the numerical simulation method of Computational Fluid Dynamics (CFD) in FLUENT software. The result of the simulation in the model shows that static pressure in this area quickly increases to its maximum then rapidly decreases to a lower fixed value from inlet to outlet along a zone between back plate and cylinder. Both rotating speeds of the cylinder and the taker-in affect static pressure from the inlet to the outlet,of which the cylinder rotating speed has more influence than that of taker-in. Numerical simulations reveal that static pressure on surface of back plate are in good agreement with the former result of experimental analysis.

Numerical simulation study of gob air leakage field and gas migration regularity in downlink ventilation

Aiming at the issue that mass of gas emission from mining gob and the gas exceeded in working face, gob air leakage field and gas migration regularity in downlink ventilation was studied. In consideration of the influence of natural wind pressure to analyze the stope face differential pressure, gob air leakage field distribution and gas migration regularity theoretically. Established a two-dimensional physical model with one source and one doab, and applied computational fluid dynamics analysis software Fluent to do numerical simulation, analyzed and contrasted to the areas of gob air leakage on size and gas emission from gob to working face on strength when using the downlink ventilation and uplink ventilation. When applied downward ventilation in stope face, the air leakage field of gob nearly working face, and the air leakage intensity were smaller than uplink, this can effectively reduce the gas emission from gob to working face; when used downlink ventilation, the air leakage airflow carry the lower amount of gas to doab than uplink ventilation, and more easily to mix the gas, reduced the possibility of gas accumulation in upper comer and the stratified flows, it can provide protection to mine with safe and effective production.

Modeling and Simulation of Skid-mounted LNG Plants Using HYSYS Software

This study presents three kinds of skid-mounted plants, including single mixed refrigerant cycle （MRC）, nitrogen expander cycle, and natural gas （NG） Claude cycle. Hysys simulation shows that single MRC is the most efficient cycle among the three. The specific power of single MRC liquefiers is 1 485 k.l/kg, 15% higher than that of large liquefaction process. Considering the recovery of stranded-gas, commercial analysis suggests that the initial cost of LNG plants ranging from 1 to 100 ms/day can be paid back in 2 to 4 years.

Numerical Simulation and Kinetic Analysis of Turbine Sail

This paper firstly introduces the structure and working principle of turbine sail. Numerical model of a turbine sail is established with Gambit software. The aerodynamic characteristics of the turbine sail are described with RNG k-e turbulence model and the numerical simulation is carded out with Fluent software. The influence of sail＇s structure is analyzed including plate, separation type and height/width ratio. The lift coefficients and drag coefficients of the simulated turbine sail are calculated under different rotation angles, suction intensity and separation plate position. The calculated results are compared with the wind tunnel experimental results, which verifies the feasibility of the numerical results and establishes a foundation for the optimal design of turbine sails.

Investigation and Verification of the Aerodynamic Performance of a Fan/Booster with Through-flow Method

Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study,a program based on the through-flow method was proposed, which had been verified by many other numerical examples. So as to improve the accuracy of the calculation, abundant loss and deviation models dependent on the real geometry of engine were put into use,such as: viscous losses,overflow in gaps, leakage from a flow path through seals. By means of this program, the aerodynamic performance of a certain high through-flow commercial fan/booster was investigated. On account of the radial distributions of the relevant parameters, flow deterioration in this machine was speculated. To confirm this surmise, 3-D numerical simulation was carried out with the help of the NUMECA software. Through detailed analysis, the speculation above was demonstrated, which provide sufficient evidence for the conclusion that the through-flow method is an essential and effective method for the performance prediction of the fan/booster.