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1.
为提高太阳能吸附集热床的集热和散热性能,本文设计了一种新型真空集热管—水冷型太阳能吸附集热床。以活性炭纤维—甲醇为工质对,建立了吸附床非动态平衡吸附传热传质数学模型。以南京夏季典型一天的太阳辐射强度和温度为条件,模拟了吸附床内各点温度、压力、吸附率等随时间的变化规律。实验研究表明,在吸附阶段通水冷却可以迅速降低吸附床的温度,并验证了所建立数学模型的合理性,为系统的进一步优化设计提供了依据。  相似文献   

2.
提出了一种太阳能制冷用热管吸附床,并通过实验与数值模拟考察了其传热性能,数值模拟表明,热管能明显地改善吸附床的传热性能,系统工作性能系数约能提高7%-10%,实验结果亦验证了这一点。  相似文献   

3.
在太阳能固体吸附循环制冷的基础上,采用无阀机构连接优化设计后的吸附床、冷凝器、蒸发器,构建成新型无阀机构的太阳能冰箱.将该太阳能冰箱分别在实验室内及实验室外进行静态实验及动态实验,得出了系统在一定辐射能量后的对外性能特性.所开展的研究工作为实用化的太阳能冰箱奠定了基础.  相似文献   

4.
实验研究了水平圆管内插入旗形件时其后掠角对30#透平油的对流传热及流阻特性的影响。实验圆管为φ24mm×2mm×700mm的紫铜圆管,后掠角为86°,81°,76°,70°,65°五种。其它参数范围为:146≤Pr≤206,1067≤Re≤6857,0.07<cos<0.42。实验范围内,换热系数首先随后掠角的增大而上升,然后又下降,在后掠角76°左右呈现出最佳值,阻力则随后掠角的增加而增加。  相似文献   

5.
NaX沸石复合吸附剂的性能与应用   总被引:11,自引:3,他引:8  
为增强固体吸附床的有效传热,提出一种以NaX沸石为主要成分的固化复合吸附剂,对其吸附性能和导热性能进行了实验研究,该复合吸附剂的吸附性能优于沸石颗粒,其最大吸附量接近于沸石原粉,吸附平衡时其导热系数约为0.23W/(m.K),试验表明,吸附剂的真实导热系数受吸附量的影响很大,而其有效导热系数除了受真实导热系数的影响外,还与吸附量的变化]率有关,对复合吸附剂在余制冷及太阳能制冷中的应用进行了探讨,提出了一种用于余热制冷的新型吸附床结构,并分析了一种结构简单的单体或太阳能制冷管。  相似文献   

6.
床径影响流化床中气-固流化行为的研究   总被引:1,自引:0,他引:1  
在不同床径(φ57,139,280和 475mm)的气-固流化床中对鼓泡流态化向湍动流态 化的流型转变进行了研究。采用密相压力信号的计算机分析作为实验手段,得到了床直 径影响流型转变的定量关联式。对床径趋于无穷大时的极限流型转变速度Uc∞(此时床 径对流型转变无影响)也进行了讨论并得到了定量结果。  相似文献   

7.
改进型太阳能固体吸附式制冰机的研制   总被引:7,自引:1,他引:7  
基于平板式太阳能制冰机的大量实验研究及理论分析计算,对太阳能固体吸附式制冰机进行了新一轮的优化设计,各子部件采用无阀连接结构,使系统操作更为简单,实验表明,系统的吸附床、冷凝器、蒸发器等子部件之间性能匹配良好,设计制作的实物样机从工艺及制造成本上均接近产业化生产的要求,为太阳能固体吸附式制冷的民用化应用提供了依据。  相似文献   

8.
根据相关标准及理论,设计了一种新型的冷凝吸附耦合的板式吸附床,并采用实验的方法,对油气回收过程中板式吸附床冷凝吸附过程的传热现象进行了研究。分别采用平均颗粒直径为2.36~3.35 mm和0.59~0.85mm的活性炭颗粒作为吸附剂,实验过程对不同吸附时间、不同颗粒直径等实验条件下床层内温度及压力分布情况进行了测量。结果表明:冷凝吸附过程受时间及孔隙率的影响较大,适当提高床层孔隙率有利于提高吸附床的传热效果,与传统的工业用吸附床相比,冷凝吸附耦合的结构可以有效降低吸附过程中床层的温度,将吸附温度控制在15℃以下,床层温升≤25℃。  相似文献   

9.
吸附制冷系统中吸附床的传热传质分析及结构设计   总被引:5,自引:1,他引:5  
对化学吸附制冷系统中吸附剂颗粒之间以及整个吸附床的传热传质特性进行了分析,并总结了目前国内外强化吸附床传热传质性能的主要措施和方法.分析比较了两种用于化学吸附制冷的典型吸附床结构,在此基础上设计了一种新型的吸附床.  相似文献   

10.
对废水通过固定吸附床的过程进行了物料衡算,确定了穿透曲线方程.通过对传质过程的分析,结合实验得出炉渣吸附床吸附厚度、吸附区下移速度及穿透时间等设计、运行参数.该参数符合运行过程,其理论分析为吸附床的设计提供了一定的理论基础.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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