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1.
Xiao-xiao XU Guang-ming CHEN Li-ming TANG Zhi-jiang ZHU Shuang LIU 《浙江大学学报(A卷英文版)》2011,12(2):146-153
This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger (IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX (EJE-IHX-S). The comparison includes the effects of changes in operating conditions such as cooling
water flow rate and inlet temperature. Experiments are conducted to assess the influence of the IHX on the heating coefficient
of performance (COPr), heating capacity, entrainment ratio, pressure lift, and other parameters. The primary flow rate of the EJE-IHX-S is higher
than that of the EJE-S. The pressure lift and actual ejector work recovery are reduced when the IHX is added to the transcritical
CO2 ejector system. Using a more practical performance calculation, the compression ratio in the EJE-S is reduced by 10.0%–12.1%,
while that of EJE-IHX-S is reduced only by 5.6%–6.7% compared to that of a conventional transcritical CO2 system. Experimental results are used to validate the findings that the IHX weakens the contribution of the ejector to the
system performance. 相似文献
2.
结合国内液氧/煤油发动机的研究,针对2种外环管切向进液流、内管进气流的同轴旋流式喷嘴,以酒精和压缩空气为工质,进行了喷雾流常压燃烧实验研究。使用红外热像仪测量了常压条件下喷雾流燃烧的温度分布,分析了火焰结构,定性研究了喷嘴形式和工况对燃烧性能的影响。 相似文献
3.
喷嘴是水射流切割系统的关键元件，通过研究一级喷嘴直径、二级喷嘴直径、混合腔直径和喉管距、系统工作压力、磨料直径大小等对轴向射流速度的影响，为水切割喷嘴的优化设计奠定了基础，其结果可为高压水切割工具的设计提供参考依据。 相似文献
4.
Zhi Huang Zhao-bo Chen Nan-qi Ren Dong-xue Hu Dong-huan Zheng Zhen-peng Zhang 《浙江大学学报(A卷英文版)》2009,10(11):1642-1650
To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages. 相似文献
5.
论述了巨型钢管合焊工序的专用设备--变截面巨型管合缝机的基本构成、运行方式、工作原理.同时对合缝机的主要结构如操纵机构、压力装置、行走系统及CO2电焊机的特点进行了分析说明,其工艺性能、生产效率、可靠性等品质达到要求,符合我国应用现状. 相似文献
6.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍｉｃｒｏｐｕｍｐｉｓｋｅｙｃｏｍｐｏｎｅｎｔｏｆｍｉｃｒｏｆｌｕｉｄｉｃｓｙｓｔｅｍ .Ｔｈｅｉｎｔｅｇｒａｔｉｏｎｏｆｍｉｃｒｏｐｕｍｐｗｉｔｈｏｔｈｅｒｍｉｃｒｏｆｌｕｉｄｉｃｃｏｍｐｏｎｅｎｔｓｃａｎｂｅｗｉｄｅ ｌｙｕ 相似文献
7.
8.
The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a） the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b） for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology. 相似文献
9.
The structure and operating principle of micro valveless pump were investigated theoretically and experimentally. The mathematical
model of pressure and flow rate within the micro nozzle/diffuser was established to analyze the effects of nozzle/diffuser
parameters on the output flow rate of the micro valveless pump. The experiments were carried out with different structural
parameters, driving frequencies, vibration amplitudes and stiffness of the driving diaphragms. Effects of the structural parameters
and driving conditions on the operation performance of the pump are discussed in detail. The work provides useful reference
for structure optimization selection of the driving diaphragm of micro valveless pump.
Project supported by National Natural Science Foundation of China (Nos. 50175098, 59835160) 相似文献
10.
与乙炔相比,无论工作性能还是气源条件,丙烷都具有相当的优势.介绍了一种新型氧气-丙烷气割嘴,以改进传统的采用氧气-乙炔的气割方式,并采用F luent软件对氧气-丙烷的混合情况进行了数值模拟,结果显示割嘴出口速度场分布均匀,氧气-丙烷的混合情况对燃烧有利,证明此种割嘴形式具有较好的混气效果. 相似文献
11.
Holger Busch Jan Hofer Athanasios Chasiotis Domingo Campos 《European Journal of Psychology of Education - EJPE》2013,28(2):239-254
Human behavior is directed by an implicit and an explicit motivational system. The intrinsic form of the implicit achievement motive has been demonstrated to predict the experience of flow. Thus, this achievement flow motive can be considered an integral component of the autotelic personality, posited in Flow Theory as dispositional difference in the propensity to experience flow. As implicit motivation predicts long-term behavioral trends and flow predicts quality of performance, the achievement flow motive should be predictive of a long-term goal pursuit such as educational attainment. This hypothesis is tested cross-culturally to shed some light on the universality of flow: Participants from Cameroon, Costa Rica, and Germany were asked about the level of education they attained. To assess their achievement flow motive, the Operant Motive Test was employed. After measurement equivalence was established, analyses revealed that, across all three cultures, the achievement flow motive explained variance in educational attainment independent of achievement values as measured by a scale of the Schwartz Value Survey. Consequently, as would be expected of an element of the autotelic personality, the achievement flow motive predicts long-term academic success. 相似文献
12.
结合工程实践中大多数注浆工程都是在动水条件下进行注浆堵水,研制了动水条件下单裂隙注浆模型试验系统,并进行了验证性试验。模型试验系统主要包括动水水源、注浆系统、模拟裂隙和数据采集系统设备。研制的模型试验系统解决了动水水源进入裂隙时为裂隙流、水头稳定、水头高度可调,注浆系统设备的注浆量可调,注浆压力和注浆速度可控,模拟裂隙设备的裂隙开度可调,裂隙粗糙度可变,扩散规律易于观察和数据易于采集,监测系统中浆液扩散、渗流压力和流出液体重量实时记录等关键问题。验证试验结果表明,模型试验系统可以在动水条件下进行单裂隙注浆试验并能获得浆液扩散规律、流出液体重量和渗流压力变化规律。 相似文献
13.
旋流喷嘴射流宏观及微观特性实验研究 总被引：2，自引：0，他引：2
对旋流喷嘴射流的宏观和微观特性 ,如表面波的发展、射流破碎过程、喷雾锥角、破碎长度等进行了实验研究 ,考察了喷嘴结构、喷射条件、射流介质的物性等对空心旋转液体射流特性的影响 .揭示了旋流喷嘴的射流特性 ,有助于旋流喷嘴的设计、应用及改进 相似文献
14.
体育学院英语专业学生学习动机的调查及其对策研究 总被引：4，自引：0，他引：4
杨成静 《绵阳师范学院学报》2005,24(3):86-89
为提高英语专业（体育外事外语方向）的教学质量，采用改建的Garner设计的态肜动机调查表，以成都体育学院英语系的90名学生为对象，调查学生的学习动机类型，以及使用英语期望及环境对学生英语学习的影响。结果表明体育外事英语方向的学习动机类型是以工具型为主的混合型，针对该类型提出了几项改进教学行之有效的策略。 相似文献
15.
Mathematical model for abrasive suspension jet cutting based on orthogonal test design 总被引：2，自引：0，他引：2
This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet (AS J) cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerf ratio of the bottom width to the top width can be determined. In 'addition, the analysis of ranges and variances are all employed to identify various factors: traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. Furthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerf ratio. Finally, the verification experiments of cutting parameters' effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ. 相似文献
16.
歌唱呼吸是发声的动力,是歌唱的基础,是歌唱的生命。歌唱中声音和气息是相互依存,相互制约,相互矛盾的两个方面。歌唱中喉头的稳定和喉咙的打开是唱好歌的前提条件。 相似文献
17.
文章介绍了双色成型的概念及其特点,分析了双色盖板的工艺,阐述了双色模具的分类及选用分体式双色模具的依据．在对模具进行总体设计规划的基础上,针对产品尺寸较小的特点,设计出特殊的浇注系统和顶出机构,其中浇注系统采用顶针潜伏式浇口转进胶槽再转侧浇口的进料方式,而顶出机构有2套顶出装置,并且将顶针分别设置在进胶槽和另一个与产品相连的类似于溢料槽的结构上,通过顶出进胶槽和溢料槽,将产品连带顶出．文章最后给出了模具的装配图及模具的工作过程． 相似文献
18.
应用XRD和催化活性评价手段,考察了助剂对CH_4与CO_2重整制合成气的负载型Ni催化剂的重整活性和其抗积炭性能的影响。实验结果表明,NiO在Υ-Al_2O_3表面上最大分散量随MgO、La_2O_3助剂的添加不同程度地增大,助剂能影响负载型Ni催化剂的催化性能,MgO、La_2O_3的添加对改善Ni催化剂的重整活性和抗积炭性能有明显效果,并与助剂的种类、添加次序有关。La_2O_3助剂的突出作用表现在维持Ni为低价还原态和促进CO_2转化等方面。 相似文献
19.
大学生入党动机教育是大学生党建工作的重要内容,90后大学生作为新时代的大学生群体,他们的价值观、人生观与其它年代的大学生具有明显区别,因此,要端正90后大学生的入党动机,高校党务工作者必需提高个人素养,给学生当好表率,同时还要加强自省与修炼,不断改进自己的工作方法,不断提高对大学生进行入党动机教育的能力,发挥学生党员的先锋模范作用,在学生中倡导自省与修炼,发挥大学生在端正自身入党动机中的主观能动性。 相似文献
20.
Reaction thrust of water jet for conical nozzles 总被引：1，自引：0，他引：1
Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system. In
this paper, theoretical, numerical and experimental studies were carried out to investigate the effects of the nozzle geometry
as well as the inlet conditions on the reaction thrust of water jet. Comparison analyses reveal that the reaction thrust has a
direct proportional relationship with the product of the inlet pressure, the square of flow rate and two-thirds power exponent
of the input power. The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence
on the reaction thrust characteristics. In addition, the best values of the half cone angle and the cylinder column length exist
to make the reaction thrust reach its maximum under the same inlet conditions． 相似文献
this paper, theoretical, numerical and experimental studies were carried out to investigate the effects of the nozzle geometry
as well as the inlet conditions on the reaction thrust of water jet. Comparison analyses reveal that the reaction thrust has a
direct proportional relationship with the product of the inlet pressure, the square of flow rate and two-thirds power exponent
of the input power. The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence
on the reaction thrust characteristics. In addition, the best values of the half cone angle and the cylinder column length exist
to make the reaction thrust reach its maximum under the same inlet conditions． 相似文献