某燃煤电厂调试阶段出现了循环冷却水量不足而导致机组停机现象,排查供水系统源头,发现取水泵运行时发生喘振,造成供水量不足,进一步引发机组停机。为保障燃煤电厂机组安全稳定运行,其取水水源需要稳定可靠,取水设施各部位尺寸应合理设...某燃煤电厂调试阶段出现了循环冷却水量不足而导致机组停机现象,排查供水系统源头,发现取水泵运行时发生喘振,造成供水量不足,进一步引发机组停机。为保障燃煤电厂机组安全稳定运行,其取水水源需要稳定可靠,取水设施各部位尺寸应合理设计。以巴基斯坦某660 MW燃煤电站海水取水工程为例,对海水取水泵房及配套设施进行物理模型试验研究,并对设计方案进行了验证,试验结果表明,推荐设计方案布置可满足HIS(hydraulic institute standards)建议值,能保证取水设备安全稳定运行。展开更多
Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical,...Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-2</sup><span style="white-space:nowrap;">·</span>s<sup>-1/2</sup> and 0.42 W<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>k<sup>-1</sup> with a thermal resistance of 0.0028 m<sup>2</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>W<sup>-1</sup>.展开更多
Introduction: Climate change causes more articulated weather conditions: at some places experts count with more droughts while at other places with more floods. Even if features of droughts and floods are total differ...Introduction: Climate change causes more articulated weather conditions: at some places experts count with more droughts while at other places with more floods. Even if features of droughts and floods are total different from each other both of them belongs to water related disaster: in case of drought amount of water is below required while in case of flood amount of water is too much. Drought and flood mean end positions of the water amount scale. Other part drones are around us: more and more applications can be seen almost all part of our life. Therefore it is very important to gather examples and finding possibilities to support water related disasters. Method: This article focuses mainly on author’s own practices and experiences using drone however practices and experiences made by others were also adapted to the results of the study as well as the examples wrote in the relevant literatures. Results: On the time scale there are three different options for using drone to support water related disaster management. Before floods drone can take river bed surveys as a kind of preventive application. During flood drone can support decision makers with the “eagle eye” view of the flooded area providing objective and relevant information. After disaster experts can use drones for mapping or remapping the affected area for making quick assessment about damages caused by the flood. In case of forest fire we can also use the above approach however in this article the flood examples of drone applications are dominated.展开更多
The study adopted a 20-foot long container to simulate the situation inside a turbine cabin. Water mist sprays were installed internally and used to perform fire extinguishing tests. Under these different scenarios, s...The study adopted a 20-foot long container to simulate the situation inside a turbine cabin. Water mist sprays were installed internally and used to perform fire extinguishing tests. Under these different scenarios, several operating factors were adjusted with the results of each adjustment subsequently measured. The operating factors studied included： operating pressures, foam concentrations, cabin opening issues, and obstacles. Each of the factors was compared with the others so as to find out which combinations would be most suitable for a water mist spray system installed inside a wind turbine cabin. The presence of obstructions hinders the direct impact of the mist spray on the fire source and in average an additional 2 to 3 minutes is required to put out the fire. This study found that the effect of the foam-water ratio is linear. Regardless of the scenario, the optimum mixture ratio is 3%. The line graph shows that the most unsuitable aqueous film-forming mixture ratio is 6%. This experiment found that the main fire extinguishing mechanism of water mist spray is the cooling of a large area via water droplets. This system is very effective in bringing down the temperature. The addition of foam in water mist spray, however, impaired the effectiveness of the cooling effect although the fire control mechanism via emulsification markedly reduced the time required to put out the fire. The increase in foam magnification will considerably enhance the fire extinguishing efficiency.展开更多
The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. ...The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.展开更多
文摘某燃煤电厂调试阶段出现了循环冷却水量不足而导致机组停机现象,排查供水系统源头,发现取水泵运行时发生喘振,造成供水量不足,进一步引发机组停机。为保障燃煤电厂机组安全稳定运行,其取水水源需要稳定可靠,取水设施各部位尺寸应合理设计。以巴基斯坦某660 MW燃煤电站海水取水工程为例,对海水取水泵房及配套设施进行物理模型试验研究,并对设计方案进行了验证,试验结果表明,推荐设计方案布置可满足HIS(hydraulic institute standards)建议值,能保证取水设备安全稳定运行。
文摘Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-2</sup><span style="white-space:nowrap;">·</span>s<sup>-1/2</sup> and 0.42 W<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>m<sup>-1</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>k<sup>-1</sup> with a thermal resistance of 0.0028 m<sup>2</sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>K<span style="white-space:nowrap;"><span style="white-space:nowrap;">·</span></span>W<sup>-1</sup>.
文摘Introduction: Climate change causes more articulated weather conditions: at some places experts count with more droughts while at other places with more floods. Even if features of droughts and floods are total different from each other both of them belongs to water related disaster: in case of drought amount of water is below required while in case of flood amount of water is too much. Drought and flood mean end positions of the water amount scale. Other part drones are around us: more and more applications can be seen almost all part of our life. Therefore it is very important to gather examples and finding possibilities to support water related disasters. Method: This article focuses mainly on author’s own practices and experiences using drone however practices and experiences made by others were also adapted to the results of the study as well as the examples wrote in the relevant literatures. Results: On the time scale there are three different options for using drone to support water related disaster management. Before floods drone can take river bed surveys as a kind of preventive application. During flood drone can support decision makers with the “eagle eye” view of the flooded area providing objective and relevant information. After disaster experts can use drones for mapping or remapping the affected area for making quick assessment about damages caused by the flood. In case of forest fire we can also use the above approach however in this article the flood examples of drone applications are dominated.
文摘The study adopted a 20-foot long container to simulate the situation inside a turbine cabin. Water mist sprays were installed internally and used to perform fire extinguishing tests. Under these different scenarios, several operating factors were adjusted with the results of each adjustment subsequently measured. The operating factors studied included： operating pressures, foam concentrations, cabin opening issues, and obstacles. Each of the factors was compared with the others so as to find out which combinations would be most suitable for a water mist spray system installed inside a wind turbine cabin. The presence of obstructions hinders the direct impact of the mist spray on the fire source and in average an additional 2 to 3 minutes is required to put out the fire. This study found that the effect of the foam-water ratio is linear. Regardless of the scenario, the optimum mixture ratio is 3%. The line graph shows that the most unsuitable aqueous film-forming mixture ratio is 6%. This experiment found that the main fire extinguishing mechanism of water mist spray is the cooling of a large area via water droplets. This system is very effective in bringing down the temperature. The addition of foam in water mist spray, however, impaired the effectiveness of the cooling effect although the fire control mechanism via emulsification markedly reduced the time required to put out the fire. The increase in foam magnification will considerably enhance the fire extinguishing efficiency.
基金Supported by National Natural Science Foundation of China(5 990 60 14 )
文摘The double fire two stage method of underground coal gasification was suggested. On the basis of material balance, the ideal gasification parameters were calculated, and the field test process was briefly introduced. In addition, the cause for a middle to a high heat value of water gas was described. And the reasonableness and feasiblity of the method was proved, showing that the double fire two stage gasification is an important technique for commercialized production.
