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431.
432.
Modeling the two-phase cloud evolution from instantaneous flashing release using CFD 总被引:1,自引:0,他引:1
Wei Tan Xiao LiuYujin Liu Yu BuZejun Wang 《Journal of Loss Prevention in the Process Industries》2011,24(4):420-425
Computational Fluid Dynamics (CFD) approach has been successfully applied to simulate the small-scale instantaneous flashing release experiment by Pettitt. A model for dispersion of the release event is provided based on relevant theories and existing experimental data. An application of the CFD method to the dispersion simulation is illustrated. Furthermore, a new methodology based on discrete phase model for setting computational initial conditions is provided. An initial expansion and subsequent turbulence dispersion can be characteristically identified from both volume and temperature variation of the cloud obtained by the simulation. The possible mechanism for these phenomena has also been discussed and analyzed. The study deepens the understanding of the physical process of this event and provides one more reliable tool for relevant safety systems. 相似文献
433.
Plastics have become an indispensable ingredient of human life. They are non-biodegradable polymers of mostly containing carbon, hydrogen, and few other elements such as chlorine, nitrogen etc. Rapid growth of the world population led to increased demand of commodity plastics. High density poly ethylene is one of the largest used commodity plastics due to its vast applications in many fields. Due to its non bio degradability and low life, HDPE contributes significantly to the problem of Municipal Waste Management. To avert environment pollution of HDPE wastes, they must be recycled and recovered. On the other hand, steady depletion of fossil fuel and increased energy demand, motivated the researchers and technologists to search and develop different energy sources. Waste to energy has been a significant way to utilize the waste sustainably, simultaneously add to meet the energy demand. Plastics being petrochemical origin have inherently high calorific value. Thus they can be converted back to useful energy. Many researches have been carried out to convert the waste plastics into liquid fuel by thermal and catalytic pyrolysis and this has led to establishment of a number of successful firms converting waste plastics to liquid fuels. This paper reviews the production and consumption HDPE, different methods of recycling of plastic with special reference to chemical degradation of HDPE to fuel. This also focuses on different factors that affect these degradations, the kinetics and mechanism of this reaction. 相似文献
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435.
In this paper, we describe the development of a model for the sustainable release of e-flows from the regional water resource infrastructure (e.g., reservoirs, rivers with available water) for lake restoration and preservation, and use the model in a case study of Baiyangdian Lake, China. First, we define the sustainable environmental flows (e-flows), with an emphasis on the ecological importance of temporal variation in factors such as water level (depth). By analyzing historical data on the suitable range of water levels in the lake, we evaluated fluctuations using canonical correspondence analysis and frequency distribution analysis. The temporal variations required by the ecosystem of the lake were also assessed. Based on this approach, we developed an optimization model for sustainable release of e-flows. We used the adaptive genetic algorithm approach to solve the model and determine the required release of e-flows. Scenario analysis then provided a range of potential management strategies for the e-flows. The optimal results are helpful to the lake managers to establish sustainable e-flow release schemes for the lake restoration and preservation. 相似文献
436.
437.
刚毛藻分解对上覆水磷含量及赋存形态的影响 总被引:1,自引:0,他引:1
在荣成天鹅湖刚毛藻暴发区域采集新鲜沉积物和刚毛藻进行室内模拟试验,定期监测上覆水中溶解氧(DO)、pH和电导率等理化参数,分析水体总磷(TP)、可溶性总磷(DTP)、可溶性磷(SRP)、溶解性有机磷(DOP)和颗粒态磷(PP)的含量变化,并探讨了刚毛藻分解对沉积物磷释放的影响.结果表明,刚毛藻分解过程中上覆水DO含量明显降低,其中30 g藻+水+沉积物处理基本维持在厌氧状态(0~0.17 mg·L-1);各处理水体pH值略有降低,加藻处理约降低了1个单位.刚毛藻分解使上覆水总磷及各形态磷含量大幅上升,且随藻量的增加,上升幅度变大,其中TP含量变化在0.04~1.34 mg·L-1之间.藻+水处理上覆水中磷的形态以DOP和PP为主,而藻+水+沉积物处理SRP含量明显升高.结果说明,刚毛藻分解过程中自身可释放大量的磷,且释放形态以PP和DOP为主;另一方面,藻类分解可明显促进沉积物中磷的释放,从而使得上覆水SRP含量大幅增加. 相似文献
438.
北京奥林匹克公园龙形水系底泥氮磷释放实验研究 总被引:1,自引:1,他引:0
以北京奥林匹克公园龙形水系底泥为研究对象,分析了典型水域底泥的理化特征,研究在不同水动力和温度条件下底泥中氮磷的释放过程。结果表明:1)龙形水系底泥理化性质对上覆水水质影响较大;2)随着水动力条件的增加总氮的释放强度增加,总磷在低流速下释放强度最大,中高流速下的释放强度均小于低流速下的释放强度,水动力条件越强氨氮释放强度越小;3)温度对底泥氮释放影响较大,较高温度能明显减小底泥总氮的释放强度,但是高温有助于提高氨氮的释放强度,而温度对底泥总磷释放的影响较小。 相似文献
439.
主要应用于舰船等有冲击场合的断路器,其抗冲击性能要求很高。介绍了断路器欠压脱扣器在抗冲击方面的设计方法,此方法可以有效地削弱冲击力对欠压脱扣器的影响。 相似文献
440.
净化铅烟用新型SV式洗涤器 总被引:1,自引:0,他引:1
SV型洗涤器净化铅烟微细颗粒,采用双级溅锥喷嘴喷雾,并通过低阻力文氏管使水滴进一步雾化,使粉尘与水滴充分接触碰撞而产生凝并,从而捕集润湿凝聚的大颗粒粉尘。再采用特殊的波纹脱水器捕集带尘水滴,使烟气脱水。同时通过水中的碱〔NaOH〕与铅粒的化学反应,增强净化效果。 相似文献