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多流股换热器网络的识别与构造 总被引:2,自引:0,他引:2
多流股换热器网络是一种新型的换热器网络。本文用改进的遗传/模拟退火算法优化综合双流股换热器网络,在此基础上进行多流股换热器网络识别和构造的研究。使网络中单个多流股换热器的换热面积最大,总的多流股换热器的换热面积也最大作为将以双流股换热器为换热设备的换热网络综合成多流股换热器网络的一个标准。通过流股匹配矩阵的使用,说明程序自动实现多流股换热器网络的识别和构造过程。文献实例证明本文提出的多流股换热器网络识别和构造方法对降低网络年度化费用是有效的。 相似文献
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分别采用固相法和溶胶-退火法合成了AgNO_(3)颗粒(分别定义为Ag NO_(3)-1和Ag NO_(3)-2),使用多巴胺对该颗粒进行表面修饰后,再以此为填充物,与P(VDF-HFP)聚合物基体复合,制备不同AgNbO_(3)填料比的(Dop@AgNbO_(3))-P(VDF-HFP)复合材料。采用X射线衍射分析仪(XRD)、扫描电子显微镜(SEM)、红外光谱仪、阻抗分析仪和铁电工作站等表征了AgNO_(3)颗粒及其复合物的物相、微观结构,探究填料合成工艺及含量对复合材料介电及储能性能的影响规律。结果表明:同一种填料合成工艺下制备的(Dop@AgNbO_(3))-P(VDF-HFP)复合物,随着填料比增加,能量密度呈现先增加后减小的趋势,在填料比6%(体积分数)时获得最高储能密度。此外,在相同的填料比下,基于溶胶-退火法合成的Ag Nb O_(3)颗粒由于粒径较小,粒度分布较窄,比表面积较大,使得(Dop@AgNbO_(3)-2)-P(VDF-HFP)复合物的整体介电和储能性能优于(Dop@AgNbO_(3)-1)-P(VDF-HFP)复合材料。例如,6%(Dop@AgNbO_(3)-2)-P(VDF-HFP)复合材料在1 kHz时的介电常数为17.6,介电损耗小于0.05;在电场80k V/mm下的有效能量密度和效率分别为0.46J/cm^(3)和71.35%。 相似文献
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Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference contribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual temperature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network (MSHEN) is regarded as an objective function, and genetic/simulated annealing algorithm (GA/SA) is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the basis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy (T-H) diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calculation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in searching the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature difference contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construction material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network (HEN) with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort. 相似文献
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采用旋转挂片腐蚀法,考察了常压塔顶酸性水的p H值、Cl-浓度以及缓蚀剂对腐蚀速率的影响,结合扫描电镜(SEM)、能谱仪(EDS)对挂片的形貌进行研究。结果表明:pH值在2~3时,20#碳钢腐蚀严重;p H值大于4时,20#碳钢的腐蚀速率趋于稳定;最佳缓蚀剂浓度为9 mg/L。添加缓蚀剂前后的扫面电镜(SEM)和能谱仪(EDS)分析显示,未添加缓蚀剂时,20#碳钢发生均匀腐蚀与点蚀,20#碳钢的腐蚀产物主要是Fe的氧化物,缓蚀剂有效的抑制了冷凝水中Cl-与金属结合,缓解了20#碳钢的腐蚀速率。 相似文献
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换热网络优化是典型的混合整数非线性规划(MINLP)问题,此问题的非线性约束以及到处存在的局部极值,使得最优解的获得尤其困难。特别是对于大规模网络来说,当物流数目增加时,可行的结构数目呈指数增长,目前还没有一种有效的算法来解决此类问题。应用改进的混合遗传算法,首先对换热网络进行初始优化,对初步优化结果进行子网络的划分,然后进行基于官能团(子网络)的重组、分解和交叉操作,获得了很好的结果。 相似文献