首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 531 毫秒
1.
污水泵站进水流态的分析及其改进   总被引:1,自引:1,他引:0  
根据上海市污水治理二期工程SA泵站水力模型试验,分析城市污水泵站前池普遍存在的不良进水流态现象及其对水泵性能的影响,提出前池流态改善措施.试验表明,改进后的前池使流态得到明显改善,水泵机组效率明显提高,并可有数降低泥沙淤积.  相似文献   

2.
上海中线2号污水泵站引水渠道和前池的试验研究   总被引:3,自引:1,他引:2  
对世界银行贷款项目--我国最大的污水治理工程污水治理二期工程中线2号污水泵站引水渠道及前汇进行了水力模型试验研究,在研究中采用清、浑水配水均匀性试验和设置压水板试验,并结合数模流场分析的方法,发现原污水泵站存在引水渠道水流流域不均匀,前池流态恶劣和泥沙淤积积严重,针对试验中的问题提出改进措施,措施效果理想,消除了前池不良流态,提高了泵站的工作效率。  相似文献   

3.
为研究开机组合对多沙水源提水泵站前池水沙流场特性的影响,以景电灌区某典型泵站为研究对象,采用逆向工程技术对淤积状态下的泵站前池三维几何模型进行重构,基于Realizable k-ε模型耦合考虑相间滑移的Mixture模型,采用FLUENT软件对淤积状态下的泵站前池开展水沙两相流数值模拟,同时对不同开机组合非淤积状态下的泵站前池水沙流场特性进行数值模拟。研究结果表明:现役淤积状态下的泵站前池内部存在流态紊乱及严重的泥沙淤积问题,流态数值模拟结果与现场测流结果相吻合;现役非淤积状态下的泵站前池存在显著的主流效应且低速回流区范围较大;伴随泵站两端机组开机,前池内主流的扩散效果有所提高,流场分布趋于对称,泥沙淤泥情况略有改善。  相似文献   

4.
我国近海挡潮闸数量多且闸下淤积严重,防淤减淤迫在眉睫。介绍了挡潮闸闸下淤积的自然原因与工程原因;总结了挡潮闸闸下淤积处理的防淤措施及减淤措施;提出未来应加强水力冲淤时间的确定及机械清淤地点的选择方面的研究,以及建闸前需加强水沙冲淤变化方面的研究模拟。  相似文献   

5.
本文通过调查和水力模型试验.在国内首次提出泵站圆形进水池在垂直双吸管条件下,最佳结构型式的各参数Dc、A、a、P、T、Hs值,通过浑水观测发现,该结构型式下产生的流态具有很强的"抑涡挟沙"能力,从而证明了圆形进水池有良好防淤效果.  相似文献   

6.
针对上海市污水治理二期工程中越黄浦江大型倒虹管泥沙冲淤问题,进行了浑水模型试验研究,模拟结果显示特别在运行初期管内会产生严重淤积,必须调整运行工况,综合模型试验及理论分析结果,并结合吴闵污水外排工程泵站实际运行能力,提 临界运行流量标准及几点管理措施。  相似文献   

7.
针对从高含沙河道取水的大型泵站直边正向前池泥沙淤积导致前池调节能力下降、泵站运行效率低下等问题,利用ICEM-CFD软件构建原型前池结构三维模型,采用FLUENT软件基于Standard k-ε湍流模型对前池流态进行模拟分析,并针对不良水流流态提出增设导流墩与压水板2种优化措施。结果表明,数值模拟结果与实际调查情况相一致,前池水流流态紊乱,泥沙淤积较严重,八字形导流墩可在一定程度上削减主回流区范围,但对前池水流仅起到分配作用,流场分布无明显改善;45°压水板能有效改善前池主流效应,两侧回流区明显减弱,在改善前池泥沙淤积问题的同时保证了水泵有利的进水条件。  相似文献   

8.
上海合流污水泵站高位井浑水模型试验研究   总被引:1,自引:0,他引:1  
运用泥沙水力学及相似理论,合理选用密度轻于天然沙的酚醛塑料沙作为模型沙,对上海市污水治理二期工程线2号污水泵站高位井进行浑水水力模型试验和数值计算,以探讨高位井的水力特性及泥沙在高位井中的沉降、冲淤,输移规律。  相似文献   

9.
火(核)电站循环水泵房前池水力模型试验研究   总被引:6,自引:0,他引:6  
根据浙江北仑电厂二期工程循环水泵房水力模型试验,分析电厂冷却水泵站前池中的不良流态及其解决方案,对泵站前人的水工布置、前池的扩散角及前池长度的设计提出了优选方案。利用该方案,不仅可较好地解决前池内流态紊乱、流速分布不均以及度坎后部次生流的产生等问题,同时可缩短前池长度、降低工程造价。  相似文献   

10.
本文在分析现有泵站的基础上,建立了有代表性的前池进水池水力模型,通过试验研究,得出了比较合理的正向前池边壁形式和进水池水平吸水管多机组运行条件下临界淹没深度的计算公式,可供泵站工程设计参考。  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.
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   

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 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   

15.
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   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
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   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
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   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号