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1.
从理论上系统地介绍了贯流式水轮机转轮叶栅几何参数中栅叶稠密度,叶的相对扭角,转轮叶片数和叶片厚度对不轮机性能的影响,并结合在同一试验台上所做的四套贯流式转轮的能量特性试验成果进行了分析和比较,得出叶栅参数对水轮机性能的影响的规律,为以后开发低水头水力资源提供了转轮设计的依据。  相似文献   

2.
以有限叶片数的旋涡气动模型为依据,用有限差分法求解描述该模型的积分微分方程,可建立一种确定水平轴风力机转轮气动性能的计算方法.该方法不只用于转轮气动正问题的求解,同时还可作为转轮气动优化设计的依据.本文先着重介绍了H.E.茹可夫斯基所提出的转轮旋涡气动模型和他所推导的求解诱导速度的表达式以及求环量分布的积分微分方程.之后,作者将积分方程已有的解法进行了改进,从而得到该方程的数值解,并提出两种求解转轮气动性能的数值解法.最后给出了转轮气动性能的几种算法的比较.  相似文献   

3.
探讨冲击式水轮机的射流干涉现象,分析了水斗在没位置的入流和出流速度三角形,指出了射流干涉对转轮效率的影响,提出提高冲击式水轮机效率的方法和途径,为冲击式水轮机的选型及结构设计提供了参考意见。  相似文献   

4.
对水力机械转轮正问题数值计算和转轮性能预估研究作了全面的评述.分析讨论了各种数值模拟方法的特点,对水力机械转轮正问题数值研究发展提出了建议.  相似文献   

5.
对新旧型谱系列模型转轮的性能进行分析,结果表明: D06 A 转轮过流能力远大于 H L160 转轮,能量特性及空化特性同时优于 H L160 转轮,但对同一导水机构 D06 A 水轮机导叶最大开度比 H L160 要大.由流道对比得出两种转轮互换性很强.实践证明用 D06 A 转轮替代 H L160 转轮可增容 20% .  相似文献   

6.
冲击式水轮机水斗内非定常自由水膜的流动非常复杂,至今还没有足够精确的数值方法来模拟这种流动.文中分析了非定常水膜流的流动机理,根据N-S方程推导出了水斗表面流体粒子在转动坐标系中的相对运动控制微分方程,依据控制微分方程编写出了数值解析软件并对水斗内的水膜流动进行了数值模拟,定量地得到了某模型水轮机水斗内部流动的速度场、能量场.对比一系列水膜流态分布,数值解析得到的结果与试验观测结果基本相吻合,最优工况下的水力效率与模型试验数据的误差为0.33%.  相似文献   

7.
固体吸附式除湿空调系统及其研究进展   总被引:5,自引:0,他引:5  
介绍几种常用的除湿方法,并通过对固体吸附除湿的工作原理及目前国内研究现状的分析,可知转轮转速、再生区扇形角、轴向质扩散等参数是影响固体转轮除湿器性能的主要因素.此外,本文进一步分析了我国固体除湿空调系统的研究现状,指出今后的研究应从高效紧凑的除湿器,高效便宜的除湿剂,高效的系统型式等方面入手,以提高系统效率,增强与传统空调系统的竞争力.  相似文献   

8.
除湿转轮除湿性能及(火用)效率分析   总被引:2,自引:0,他引:2  
建立了除湿转轮(火用)效率模型,应用除湿转轮传热传质数学模型和实验装置分析了通道中湿空气的(火用)及炯效率,研究了影响(火用)效率及除湿性能的因素.结果显示:吸附通道中作为收益的扩散戈用所占比例较小,表明除湿转轮的(火用)效率较低,回收再生过程排气中的热(火用)可以提高装置(火用)效率;当传递单元数NTU在0-2.5时.除湿转轮的(火用)效率及除湿性能随NTU的增加而迅速升高,当NTU2.5时,这一趋势变缓;除湿转轮在最佳转速下运行时其除湿性能及(火用)效率同时迭最大;提高再生温度可以提高除湿转轮的除湿性能,但其(火用)效率却随再生温度的增加而下降.  相似文献   

9.
CFD法研究多喷嘴冲击式水轮机的射流干涉   总被引:5,自引:1,他引:5  
为提高冲击式水轮机的比转速和出力,通常采用增加喷嘴数的办法,然而增加喷嘴数会引起射流干涉,降低水轮机的水力效率.文中研究了射流干涉的产生机理,通过计算相邻两射流之间的动画单元数、水斗接受最后一滴射流的动画单元数、发生射流漏损时无效射流恰与水斗分离的动画单元数以及两相邻射流相交的动画单元数,提出了相邻两射流间发生干涉的判别式.利用所提出的判别式预测了不同喷嘴数和水斗数时冲击式水轮机的射流干涉情况,所得结果证明了判别式的有效性.  相似文献   

10.
干燥剂转轮动态除湿特性实验研究   总被引:6,自引:1,他引:5  
利用除湿量D和除湿性能系数DCOP两种评价指标的动态变化,通过实验比较了硅胶和氯化锂转轮在相同工况下到达稳定状态之前的动态除湿特性。研究了运行参数(再生温度,处理风量,处理空气进口温度、湿度)对转轮稳态前动态除湿性能的影响。结果表明,在同种工况下,氯化锂转轮非稳态过渡时间比硅胶转轮要长,氯化锂转轮的D和DCOP都始终高于硅胶转轮;再生温度、处理风量和处理空气进口湿度的影响比较大,处理空气进口温度的影响比较小。  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.
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   

19.
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   

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   

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