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1.
热水型LiBr制冷机中两相流提升管的强化传热研究   总被引:2,自引:1,他引:2  
对LiBr溶液在3种不同截面尺寸弦月形通道中的沸腾传热及热虹吸提升过程进行了实验研究,发现在相同的条件下,通道间隙尺寸对传热及溶液提升有直接影响,其中两管直径之比为19∶32的弦月形通道提升管的提升效果最好,溶液的净提升高度可达到稀溶液浸没高度的2.5倍,是目前国内的最大提升高度,同时比现行发生器所需热源温度降低10℃左右;随着热流密度的增大和加热水温度的升高,冷剂水产量和提升管出口气体质量分数均增大;提升管出口处的气体质量分数随着试件浸没深度的增大而减小.  相似文献   

2.
无泵溴化锂吸收式制冷机二次发生器的实验研究   总被引:3,自引:0,他引:3  
在太阳能无泵溴化锂吸收式制冷系统降膜吸收器、降膜蒸发器、弦月形热虹吸提升管、冷凝器等主要部件的基础上,设计了一套二次发生器,有效地降低了热源温度(最低启动温度为68℃,稳定运行温度范围为80-93℃),提高了太阳能的利用率.二次发生器在提高系统冷凝器与蒸发器间压差的同时,使系统能在较低的溶液初始质量分数范围(46%~54%)下运行,放气范围可达6%,吸收率是二次发生器关闭时的3倍,有助于提高吸收器性能;冷剂水产量提高,是相应未开二次发生装置时冷剂水产量的1.68倍,蒸发效果明显改善;随着加热水温度和吸收器浓溶液温度的升高,吸收器冷却水温差和冷媒水温差均增大,冷媒水出口温度降低,改善了制冷系统的整体运行性能,平均制冷系数可达0.725.  相似文献   

3.
于传波  张泉  邹思凯 《科学技术与工程》2023,23(28):12091-12100
分离式热管系统通常依据服务器负载变化来调节背板风量,降低数据中心的运行能耗和提升设备的安全性,但风量降低会影响服务器芯片散热效率,可能造成芯片过热失效。为了分析风量变化对芯片热安全的影响,基于机柜、服务器和芯片的结构和运行参数在ICEPAK中建立机柜物理模型,并耦合分离式微通道热管一维稳态换热模型,描述数据机房用热管背板冷却机柜服务器的全流程换热过程,研究了不同服务器负载下风量对芯片温度的影响。在标准工况下(机房温度27 ℃,冷水进水温度18 ℃,风量1 400 m3/h),当服务器负载为6 kW时,芯片平均温度为54.1 ℃,热管的能效比为60。在满足机柜冷量需求的基础上,降低风量至额定风量(1 400 m3/h)的43%(600 m3/h),会使得芯片散热器表面平均风速降低37%,芯片与空气之间的热阻升高35%,导致芯片温度和服务器排风温度分别升高至75.7 ℃和56.5 ℃。此时,芯片依然在安全温度(<85 ℃)运行,热管背板的能效比提升了132%。当服务器负载降低为4 kW和2 kW时,在保证芯片安全运行的前提下,可分别降低背板风量70%和85%,热管背板的能效比提升245%和600%。  相似文献   

4.
重油催化裂化装置提升管在线取样研究   总被引:1,自引:0,他引:1  
利用自行研制的工业提升管在线取样系统对胜利石化总厂重油催化裂化装置提升管进行了在线取样,并对取得的液体和催化剂样品进行了分析,从而得到了重油催化装置提升管反应器中液体产品分布、催化剂活性、催化剂上碳含量沿提升管高度的变化规律。重油催化裂化反应主要发生在提升管的中下部区域,改善产品分布和优化反应进程必须在此区域采取措施,应对该区域的反应参数(反应温度、催化剂性能及进料性质等)进行控制。在提升管油剂混合处,催化进料并没有完全汽化,仍有部分重组分以液相存在,这对提升管反应器内的反应过程不利,易使提升管喷嘴上方区域结焦。  相似文献   

5.
为了降低数据中心的运行能耗,分离式热管冷却系统会根据实际负载降低风扇转速,造成换热性能的衰减. 为了对低风量和低负载下分离式微通道热管的换热性能进行研究和分析,建立了适用于预测低风量下分离式微通道热管换热性能的一维稳态模型,并与试验结果对比,验证了模型的准确性,其最大预测平均偏差为6.3%. 利用该模型研究了运行参数对分离式微通道热管的换热性能和数据中心热安全的影响. 不同风量下,服务器排风温度从27 ℃上升至39 ℃时,系统换热量均有超过60%的提升;冷冻水供水温度从6 ℃提升至18 ℃会导致系统换热量最高下降41.8%. 在200~1 400 m3/h风量下,增加蒸发器和冷凝器的高度差可有效提升系统换热量和制冷剂质量流量,风量越大,换热量增长率越高. 但在相同风量下,随着高度差的逐渐增大,换热量增长率逐渐降低. 研究结果对分离式微通道热管在数据中心的设计优化和节能运行有一定促进作用.  相似文献   

6.
应用两相流和溶液热力学的基本理论对热虹吸提升管的流动特性进行了分析研究,采用两相流分相模型对其进行了数值计算,得出了对应不同截面、不同浸没高度下加热负荷与浓溶液的提升量、蒸汽发生量、浓溶液最大提升高度及稀溶液最小浸没高度的关系曲线.分析结果表明:在小加热负荷下(7.0 kW左右),直径比为19/32的组合套管的提升高度优于其他套管,最大提升高度高于直径比为16/32的组合套管.计算结果与实验结果符合良好,为该类型热虹吸泵的设计和运行提供了依据.  相似文献   

7.
根据系统各单元对压力的需求以及系统设计参数与流型参数之间的内在关系,对小型太阳能无泵溴化锂(LiBr)吸收式制冷机中受全程加热的溶液提升管所需的最低高度进行了理论计算,给出了算例.计算结果说明,对溶液提升管高度提出要求的主要是稀溶液的设定浸没高度和吸收器的设计高度,分别占总高度要求的50%和25%左右.在提升管中为弹状流的形态下,所需溶液提升管的高度可以比传统装置的设计高度降低20%。  相似文献   

8.
针对吸收式太阳能海水淡化系统,设计了一套竖管降膜吸收实验装置,以溴化锂溶液为工质对装置进行了实验研究.通过改变水和溶液温度、喷淋量及溶液的浓度,测试了不同工况下系统的运行情况,得出溶液具有较好吸收率的基本条件,给出了系统最佳运行的参数范围.实验表明,在运行压力达到10 kPa和溶液浓度为50%左右的情况下,当被吸收水的温度高于30℃时,溶液已有较好的吸收速率,此时热源的温度仅为45℃~55℃,这十分有利于太阳能集热系统发挥供热效率.  相似文献   

9.
利用Pechini法合成了SrAl4O7,研究了溶液pH和柠檬酸与金属离子摩尔比n(CA)/n(M)对SrAl4O7结晶过程的影响,确定了SrAl4O7随时间和温度的稳定范围.结果表明,增加溶液pH和n(CA)/n(M)有利于形成SrAl4O7.当n(CA)/n(M)=2时,在900℃,加热2h,从pH=7的前驱体形成单相的SrAl4O7;若不调节pH,即使在1100℃,加热2h也不能形成单相的SrAl4O7.当n(CA)/n(M)增加到4时,对不调节pH的前驱体,在1100℃,加热2h形成单相的SrAl4O7;调节溶液pH=7,单相的SrAl4O7的形成温度降低到900℃,2h.SrAl4O7至少能在1400℃稳定2h,在1500℃开始分解.  相似文献   

10.
在剧烈搅拌下,将饱和的α-环糊精(α-CD)水溶液滴加到60℃的聚己二酸乙二醇酯(PEA)溶液中,制备了两者的包合物(PEAIC)。利用红外光谱(FTIR)、广角X线衍射分析(WAXS)、差示扫描量热分析(DSC)和热重分析(TGA)分别对包合物的结构和性能进行了表征和测试。研究结果表明,PEA可以和α-CD发生非共价键作用,形成隧道状晶体结构;在α-CD的包裹下,PEAIC的结晶和熔融行为几乎消失;与纯PEA相比,PEAIC的热失重温度提高了68℃。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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