深度碳分技术在工业生产中的应用

烧结法碳分母液深度碳分技术是国家"十五"科技攻关课题组开发的一项技术。该技术在混联法氧化铝厂应用,可减少生产流程中氧化铝的循环量,提高烧结法系统的生产能力和碳分母液的蒸发浓度;将深度碳分产品加入拜耳法种分系统后可直接提高产量,且成本较低,是混联法氧化铝厂提产降耗的一种有效途径。

Effects of the profile of a supercavitating vehicle's front-end on supercavity generation

The authors designed three different front profiles for supercavitating vehicles based on cavity theory and the Granville streamlined equation are designed. Experiments were done using these front profiles in the Northwestern Polytechnical University high-speed water tunnel. The experiments indicated that the critical volume of gas required for supercavitation is affected by the axial distribution of the front-end＇s slope. The experimental data showed critical gas flow rates required for the three designs were less than rood-l, with the greatest decrease 24%. The experimental results also showed the supercavitation generation speeds of the models were faster than mod-1 by up to 32.4%. This verifies that the front profile of a supercaviting vehicle effects supercavity generation speed and critical gas flow rates. The smaller the changes in axial distribution of pressure, the higher the supercavity generation speed. The smaller the changes in curvature distribution of axial, the smaller the critical gas flow rates.

Flotation characteristics of Shenfu coal macerals

The flotation characteristics of Shenfu coal macerals was researched. Taking flotation recovery and enrichment of macerals as the evaluation objects, the influence of the agent dosage, pulp concentration, impeller speed and aeration rate on the separating effect was investigated. And the optimum process conditions of flotation were confirmed. The results show that the agent dosage, pulp concentration, impeller speed and aeration rate have a significant impact on flotation recovery and en- richment of macerals. The float recovery was 73.28% and enrichment ratio of vitrinite was 83.89% when CTAB dosage of 1.0 kg/t, pulp concentration of 100 g/L, impeller speed of 1 700 r/min and aeration rate of 0.25 m3/（m2·min） were used. The tailings yield was 60.30% and enrichment ratio of inertinite was 61.44% when CTAB dosage of 0.5 kg/t, pulp concentration of 100 g/L, impeller speed of I 700 r/min and aeration rate of 0.20 m3/（m2·min） were used.

Airflow adjustment and minimization of the air power of ventilation network

It is often required to know which roadway （adjustment roadway） resistances and how much values of the resis- tances should be changed to make the airflow rates in roadways （target roadways） to certain required values in the practice of mine ventilation. In this case, the airflow rates of the target roadways and the resistances of the roadways other than the ad- justment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found. No straightforward method to solve the problem has been found up to now. Therefore, trial and error method using the ventilation network analysis program is utilized to solve the problem so far. The method takes long calculation time and the best answer is not necessarily obtained. The authors newly defined ＂airflow element＂ as an element of the ventilation network analysis. The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis. The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method. The authors made the computer program fulfill the method. The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.

Hydrodynamics features of dispersed bubbles in the ventilated wake flow of a cylinder

An experimental study was conducted to investigate the 2 D bubbly flow downstream of a cylinder. Sparsely distributed bubbles were produced using the ventilation method. The carrier flow was measured using the particle image velocimetry(PIV) technique. The shadow imaging technique was used to capture instantaneous bubbly flow images. An image-processing code was compiled to identify bubbles in acquired image, calculate the bubble equivalent diameter and the bubble velocity. The effects of Reynolds number and the flow rate of the injected air were considered. The result indicates that the carrier flow is featured by distinct flow structures and the wake region is suppressed as the upstream velocity increases. Regarding the bubbles trapped in the wake flow, the number of small bubbles increases with the upstream velocity. On the whole, the bubble velocity is slightly lower than that of the carrier flow. The consistency between small bubbles and the carrier flow is high in terms of velocity magnitude, which is justified near the wake edge. The difference between the bubble velocity and the carrier flow velocity is remarkable near the wake centerline. For certain Reynolds number, with the increase in the air flow rate, the bubble equivalent diameter increases and the bubble void fraction is elevated.

Numerical analysis of aerated heap bioleaching with variable irrigation and aeration combinations

Forced aeration is an effective way to accelerate the heap bioleaching process.To reveal the effects of different irrigation and aeration combinations on bioleaching performance of copper sulfides,numerical simulations with COMSOL were carried out.Results showed the oxygen concentration is the highest at the bottom with forced aeration,the airflow transports spherically from the aeration pipeline to the slope,and the horizontal diffusion distance is further than vertical value.When the irrigation-to-aeration ratio is higher,the average heap temperatures are mainly decided by aeration rates;otherwise,temperature distributions are the equilibrium of mineral reaction heat,the livixiant driven heat and the airflow driven heat.When the aeration rate is higher than 0.90 m3/(m2·h),oxygen concentration is no longer a limiting factor for mineral dissolution.Additionally,on the premise of sufficient oxygen supply,Cu recovery rate is higher at the bottom with low irrigation rate;while it is higher at upper regions with high irrigation rate.The numerical analysis uncovered some insights into the dynamics and thermodynamics rules in bioleaching of copper sulfides with forced aeration.

SURFACE OBSERVATIONS IN THE TROPICAL CYCLONE ENVIRONMENT OVER THE SOUTH CHINA SEA

In this paper, the observational data from Marine and Meteorological Observation Platform （MMOP） at Bohe, Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature and specific humidity difference and the relationship between wind and wave with the tropical cyclones over the South China Sea （SCS）. The heat and momentum fluxes from eddy covariance measurement （EC） are compared with these fluxes calculated by the COARE 3.0 algorithm for Typhoon Koppu. The results show that at the developing and weakening stages of Koppu, both these differences between the sea surface and the near-surface atmosphere from the MMOP are negative, and data from the buoys also indicate that the differences are negative between the sea surface and near-surface atmosphere on the right rear portion of tropical cyclones （TCs） Molave and Chanthu. However, the differences are positive on the left fi＇ont portion of Molave and Chanthu. These positive differences suggest that the heat flux is transferred from the ocean to the atmosphere, thus intensifying and maintaining the two TCs. The negative differences indicate that the ocean removes heat fluxes from the atmosphere, thus weakening the TCs. The wind-wave curves of TCs Molave and Chanthu show that significant wave height increases linearly with 2-min wind speed at 10-m height when the wind speed is less than 25 m/s, but when the wind speed is greater than 25 m/s, the significant wave height increases slightly with the wind speed. By comparing the observed sensible heat, latent heat, and friction velocity from EC with these variables from COARE 3.0 algorithm, a great bias between the observed and calculated sensible heat and latent heat fluxes is revealed, and the observed friction velocity is found to be almost the same as the calculated friction velocity.

气提式污水泵站供气系统的设计和计算方法探讨

通过搭建气提式污水泵站试验平台,对气提污水泵在不同通气量下的特性参数进行测试。分析进气管在不同通气速度和扬水管在不同淹没比时的进气压力变化规律,获得了进气管的经济通气速度和通气压力计算方法。不同淹没比扬水管的通气量与扬水量的变化规律表明,应根据淹没水深的变化调节气提污水泵的通气量。对气提污水泵常用的通气量计算公式进行分析探讨,并根据试验数据进一步对其计算值进行验证,结果表明Nicklin公式的计算值与实测值吻合度较高。建议采用Nicklin公式进行通气量计算,并根据最低淹没比选取合理的效率值。

Experimental demonstration of the coupling effect of vertical velocity on latent heat flux

According to the cross coupling theorem of atmospheric turbulence, latent heat flux comprises two components, a vertical humidity gradient flux and a coupling flux of vertical velocity. In this paper, observational data are employed to demonstrate and analyze the coupling effect of vertical velocity on latent heat flux. The results highlight the presence of a coupling zero-effect height. When the observational level exceeds or underlies the coupling zero-effect height, the coupling effect suppresses or enhances the latent heat flux, respectively. Above the heterogeneous terrain in the experimental region, the overall difference between the estimated and the observed latent heat fluxes decreases from 27% to 2% (for ascending flow) and from 47% to 28% (for descending flow), after compensating for gradient flux. The coupling theorem of atmospheric turbulence is well validated by our analysis, supporting a role for experimental datasets in unraveling the mysteries of atmospheric turbulence.