The unavailability of wasted energy due to the irreversibility in the process is called the entropy generation.An irreversible process is a process in which the entropy of the system is increased.The second law of the...The unavailability of wasted energy due to the irreversibility in the process is called the entropy generation.An irreversible process is a process in which the entropy of the system is increased.The second law of thermodynamics is used to define whether the given system is reversible or irreversible.Here,our focus is how to reduce the entropy of the system and maximize the capability of the system.There are many methods for maximizing the capacity of heat transport.The constant pressure gradient or motion of the wall can be used to increase the heat transfer rate and minimize the entropy.The objective of this study is to analyze the heat and mass transfer of an Eyring-Powell fluid in a porous channel.For this,we choose two different fluid models,namely,the plane and generalized Couette flows.The flow is generated in the channel due to a pressure gradient or with the moving of the upper lid.The present analysis shows the effects of the fluid parameters on the velocity,the temperature,the entropy generation,and the Bejan number.The nonlinear boundary value problem of the flow problem is solved with the help of the regular perturbation method.To validate the perturbation solution,a numerical solution is also obtained with the help of the built-in command NDSolve of MATHEMATICA 11.0.The velocity profile shows the shear thickening behavior via first-order Eyring-Powell parameters.It is also observed that the profile of the Bejan number has a decreasing trend against the Brinkman number.Whenηi→0(i=1,2,3),the Eyring-Powell fluid is transformed into a Newtonian fluid.展开更多
在德国促进联合工业研究发展计划(IGF)的19617 N号研究项目中,制备了氮和磷取代的烷氧基硅烷,并对其抑制织物火势生长和蔓延的能力进行了研究。为此,采用不同的策略合成了一系列阻燃剂,包括用氨基三烷氧基硅烷和/或三聚氰胺对有机磷化...在德国促进联合工业研究发展计划(IGF)的19617 N号研究项目中,制备了氮和磷取代的烷氧基硅烷,并对其抑制织物火势生长和蔓延的能力进行了研究。为此,采用不同的策略合成了一系列阻燃剂,包括用氨基三烷氧基硅烷和/或三聚氰胺对有机磷化合物进行点击化学和亲核取代。采用轧-烘-焙工艺和溶胶-凝胶法,将新型无卤、无醛阻燃剂应用于棉(CO)、聚对苯二甲酸乙二醇酯(PET)、聚酰胺(PA)及其混纺织物上。阻燃效率通过EN ISO 15025测试方法评估。此外,通过附着在磷原子上的官能团或焙烘温度的优化,可控制阻燃剂的水溶性和耐洗性。总体而言,该项研究表明,N-P-硅烷是良好的纺织品耐久性阻燃剂。展开更多
传统的饮用水和废水处理技术对全氟化碳(PFCs)的去除存在一定的局限性。因此,需要一种先进的全氟化碳去除技术。以聚酯纤维(PET)为基材,采用不同的聚电解质[聚乙烯胺(PVAm)、β-环糊精改性的PVAm和季铵盐改性的PVAm]进行涂层处理,制备...传统的饮用水和废水处理技术对全氟化碳(PFCs)的去除存在一定的局限性。因此,需要一种先进的全氟化碳去除技术。以聚酯纤维(PET)为基材,采用不同的聚电解质[聚乙烯胺(PVAm)、β-环糊精改性的PVAm和季铵盐改性的PVAm]进行涂层处理,制备了吸附织物,用于去除地下水和工业废水中的PFCs。这种吸附用纺织品是用热轧的方法加工而得的,耐用、性能优良、成本效益可观。PVAm改性的PET对长链全氟碳化合物具有较高的吸附能力,而环糊精或季铵盐类化合物的改性,提高了PET对短链全氟碳化合物的选择性。采用1.5 m 3的中试装置对3种不同来源的受污染地下水进行现场试验。测试结果表明:来自杜塞尔多夫机场附近和在德国一家前纺织整理公司获得的受污染的地下水中的全氟化合物,分别减少了约95%的长链和85%的短链全氟化合物。此外,被短链全氟化碳高度污染的纸质污泥产生的地下水中的PFCs去除率略低。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11971142,11871202,61673169,11701176,11626101,and 11601485)。
文摘The unavailability of wasted energy due to the irreversibility in the process is called the entropy generation.An irreversible process is a process in which the entropy of the system is increased.The second law of thermodynamics is used to define whether the given system is reversible or irreversible.Here,our focus is how to reduce the entropy of the system and maximize the capability of the system.There are many methods for maximizing the capacity of heat transport.The constant pressure gradient or motion of the wall can be used to increase the heat transfer rate and minimize the entropy.The objective of this study is to analyze the heat and mass transfer of an Eyring-Powell fluid in a porous channel.For this,we choose two different fluid models,namely,the plane and generalized Couette flows.The flow is generated in the channel due to a pressure gradient or with the moving of the upper lid.The present analysis shows the effects of the fluid parameters on the velocity,the temperature,the entropy generation,and the Bejan number.The nonlinear boundary value problem of the flow problem is solved with the help of the regular perturbation method.To validate the perturbation solution,a numerical solution is also obtained with the help of the built-in command NDSolve of MATHEMATICA 11.0.The velocity profile shows the shear thickening behavior via first-order Eyring-Powell parameters.It is also observed that the profile of the Bejan number has a decreasing trend against the Brinkman number.Whenηi→0(i=1,2,3),the Eyring-Powell fluid is transformed into a Newtonian fluid.
文摘在德国促进联合工业研究发展计划(IGF)的19617 N号研究项目中,制备了氮和磷取代的烷氧基硅烷,并对其抑制织物火势生长和蔓延的能力进行了研究。为此,采用不同的策略合成了一系列阻燃剂,包括用氨基三烷氧基硅烷和/或三聚氰胺对有机磷化合物进行点击化学和亲核取代。采用轧-烘-焙工艺和溶胶-凝胶法,将新型无卤、无醛阻燃剂应用于棉(CO)、聚对苯二甲酸乙二醇酯(PET)、聚酰胺(PA)及其混纺织物上。阻燃效率通过EN ISO 15025测试方法评估。此外,通过附着在磷原子上的官能团或焙烘温度的优化,可控制阻燃剂的水溶性和耐洗性。总体而言,该项研究表明,N-P-硅烷是良好的纺织品耐久性阻燃剂。
文摘传统的饮用水和废水处理技术对全氟化碳(PFCs)的去除存在一定的局限性。因此,需要一种先进的全氟化碳去除技术。以聚酯纤维(PET)为基材,采用不同的聚电解质[聚乙烯胺(PVAm)、β-环糊精改性的PVAm和季铵盐改性的PVAm]进行涂层处理,制备了吸附织物,用于去除地下水和工业废水中的PFCs。这种吸附用纺织品是用热轧的方法加工而得的,耐用、性能优良、成本效益可观。PVAm改性的PET对长链全氟碳化合物具有较高的吸附能力,而环糊精或季铵盐类化合物的改性,提高了PET对短链全氟碳化合物的选择性。采用1.5 m 3的中试装置对3种不同来源的受污染地下水进行现场试验。测试结果表明:来自杜塞尔多夫机场附近和在德国一家前纺织整理公司获得的受污染的地下水中的全氟化合物,分别减少了约95%的长链和85%的短链全氟化合物。此外,被短链全氟化碳高度污染的纸质污泥产生的地下水中的PFCs去除率略低。
