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1.
界面接触热阻的研究进展   总被引:12,自引:4,他引:8       下载免费PDF全文
张平  宣益民  李强 《化工学报》2012,63(2):335-349
界面接触热阻(TCR)是电子器件冷却、低温超导薄膜等领域研究中的一个热点。综合评述了对接触热阻的传热机理的研究方法、测量方法以及减小接触热阻的主要措施,介绍了近年来国内外对接触热阻的最新研究成果和进展,现有的研究表明:对于界面接触热阻这一特殊物理问题,其理论研究既要从宏观上定量分析又要在微观上综合考虑声子、电子的散射、辐射等机理;在实验方面,目前的测量精度不够高,实验测量工作有待进一步地完善;在减小接触热阻方面,除了常用的方法外,可以通过在接触表面生长新型的高性能导热材料(碳纳米管等)来实现。对已报道的研究工作进行了总结,指出了今后的研究方向。  相似文献   

2.
对磁性液滴在不互溶液体中的运动和接触传热特性进行了实验研究和理论分析,建立了磁性液滴在不互溶液体中运动的数学模型和传热关联式。实验结果表明,外加磁场对磁性液滴的流动和传热具有显著的强化作用。  相似文献   

3.
研究了垂直管内连续相水和分散相戊烷泡滴之间的流动和传热性能 .在全面考虑了汽体的膨胀、水蒸气的蒸发、界面张力的作用、汽液两相的相互作用和滑移、泡滴的破碎等影响因素的基础上 ,建立了与实验结果吻合较好的一维流体力学模型和传热模型  相似文献   

4.
吸附剂之间及其与铜表面之间的传热强化研究   总被引:2,自引:0,他引:2  
测试了颗粒吸附剂(沸石/聚苯胺复合物)、成型吸附剂与铜表面之间的接触热阻以及导热胶对吸附剂与铜表面之间的接触热阻的影响。结果表明,成型吸附剂能有效地强化吸附剂与铜表面之间的传热, 导热胶能进一步强化吸附剂与铜表面之间的传热。  相似文献   

5.
酒精液滴在蔗糖溶液中汽化冷却传热及其结晶过程   总被引:7,自引:0,他引:7  
在一汽升式循环管中于减压条件下研究了冷剂酒精在高粘度高浓度的蔗糖水溶液中直接接触汽化传热过程,讨论了冷剂流量,冷剂进口温度和蔗糖溶液的粘度和浓度等操作条件对体积传热量的影响。实验结果表明:冷剂流量Vd=0.9 ̄1.9ml/min,冷剂进口温度为45 ̄60℃时,传热效果较好,在此基础上初步探讨了酒精汽化冷却法制取蔗糖晶核的过程,利用显微照相技术分析了晶核的外观特性。  相似文献   

6.
《化学工程》2017,(12):30-34
为了研究戊烷与水直接接触汽化传热过程中其液液界面的真实传热温差,文中搭建了汽化传热的闭路循环实验装置,设计了一种戊烷-水直接接触界面面积不变的圆形接触面,运用双平行电导探针测定液液界面的波动情况,采用红外热像技术确定液液界面处水的表面温度,进而确定直接接触汽化传热的真实传热温差,同时通过实验研究了水流速和温度对热通量的影响。结果表明:戊烷汽化传热的真实传热温差Δt远远小于传统计算方法得到的温差Δt_m,这种温差的差别导致了计算得到的真实传热系数远远大于根据传热方法计算得到的传热系数。同时,热通量随着水流速和传热温差的增加而逐渐增加。该实验方法为直接接触汽化传热机理的研究提供了重要方法和新的思路。  相似文献   

7.
移动床中颗粒接触传热的数学模型   总被引:6,自引:2,他引:6       下载免费PDF全文
密相颗粒流动过程中的传热行为研究还不充分.在综合考虑颗粒接触传热的多个过程的基础上提出了颗粒接触传热模型,并与DEM模型结合模拟了移动床中颗粒与加热面间的传热过程.比较各传热过程的关系,可知通过接触面传递的热量对整体有效传热量的影响最大;有效传热系数主要受与加热面接触的颗粒数目、接触时间、颗粒 加热面间接触面的大小等因素的影响;当颗粒的平均粒径相同时,不同的颗粒粒径分布对颗粒系统的传热影响不是很大;当颗粒的粒径增大,有效传热系数降低;颗粒与加热面间的传热量在空间上的分布是不均匀的.  相似文献   

8.
垂直管内不互溶液滴群直接接触汽化传热   总被引:2,自引:0,他引:2  
在一气升式外循环实验设备中研究了冷剂正戊烷与热流体水在垂直管内直接接触汽化传热过程。根据单液滴不互溶冷剂汽化关联式,推导出多液滴汽化过程中局部和平均体积传热系数表达式,表达式较好地解释了实验结果。讨论了冷剂表观流速、冷剂与热流体间的传热温差对体积传热量qv和体积传热系数av的影响;以及冷剂表观流速对冷却温差的影响。  相似文献   

9.
用于热敏物料蒸馏的直接接触传热蒸发釜的研究   总被引:2,自引:0,他引:2  
胡朋飞  崔现宝  杨志才 《化工进展》2002,21(Z1):158-161
针对热敏物料蒸馏中存在的技术难题,提出了一种用熔盐直接加热热敏物料的新方法.该方法中传热系数很大,传热表面积可不断扩充、更新,所以理论上传热温差可以达到很小,而热敏料液在釜内的停留时间大大缩短(≤1s),所以该方法在热敏物料的蒸馏上具有广泛的应用前景.文中给出了用熔盐和不用熔盐两种情况下加热蒸发DEP的实验结果并进行了比较,而且还给出了熔盐与分散相之间的传热速率的各种影响因素及曲线.  相似文献   

10.
采用金属内衬外部缠绕纤维增强复合材料,可减轻纯金属身管重量,提高身管刚度.为了详细分析复合材料身管分界面接触热阻对身管热性能影响,本文建立考虑复合材料身管分界面接触热阻效应的瞬态传热模型,运用有限差分法编制通用程序对接触热阻效应对复合材料身管热性能影响进行数值定量分析.结果表明,接触热阻对于复合材料身管的传热性能有较大影响,必须采取措施来减小接触热阻,这在复合材料身管的热性能设计中必须重点考虑.  相似文献   

11.
雷玲  徐汉虹  邓业成  胡林 《农药》2006,45(12):818-820
制备出苏云金芽孢杆菌(B.t.)β-环糊精包合物,并对包合物进行了差热分析,证明B.t.原粉被β-环糊精包合。室内生物活性测定结果表明,当B.t.原粉与β-环糊精质量比为0.5:2时,包合物对棉铃虫2龄幼虫的杀虫活性最高,确定包合物中B.t.原粉与肛环糊精的最佳质量比为0.5:2。盆栽药效试验结果表明,当B.t.原粉制成环糊精包合物后,与B.t.原粉和B.t.制剂相比,对小菜蛾的防效明显提高。药剂处理后1、3、7d,B.t.环糊精包合物对小菜蛾的防效分别为41.67%、61.54%和60.00%,而B.t.原粉和制剂的防效分别为23.61%、38.46%、32.00%和31.94%、52.31%、46.00%。  相似文献   

12.
Conclusions Questions of the method of production of basic ramming compounds at Panteleimonovka Refractory Plant and their use in the monolithic lining of the walls of 160-ton steel-teeming ladles of the No. 2 Converter Shop of Kirvoi Rog Steel Combine are considered.An analysis of the wear of the lining during service showed that it occurs as the result of spalling of the sintered zone and salamandering of the lining. The use of a movable thermally insulated lid made it possible to hold the temperature of the ladle lining within limits of 730–1120°C between heats and to obtain a basic rammed lining life of 21–39 heats as opposed to an average life for the shop of 14.8 heats.A reserve for increasing the ladle basic lining life is optimization of the thermal conditions of its service, including high-temperature heating of the lining before pouring of the metal, the use of thermally insulated lids with the minimum consumption of time for placing of them, an increase in the life of the well refractory to the life of the walls and bottom, and elimination of cooling of the lining between heats.A Discussion: Problems of the Production and Use of Refractories for the Lining of Steel-Teeming Ladles. [For the start of the discussion see No. 8 (1988) and for the continuation Nos. 9–12 (1988) and Nos. 1–3, 5, and 7 (1989).]Deceased.I. I. Glaka, N. F. Drobot, N. V. Kurmaz, B. P. Zinchenko, S. A. Poznyak, I. M. Ryaboshapkin, V. V. Slushko, A. A. Chulkov, Yu. Bormatov, S. I. Vanchyuk, V. I. Dobrovol'skii, B. G. Zhuravel', N. I. Kiyan, L. I. Nekrasov, N. M. Sokolov, P. V. Khomenko, G. A. Nikitenko, S. Dorgobuzov, P. I. Valiev, N. N. Gorbatko, V. I. Kovalenko, and M. I. Lyakhov of Krivoi Rog Steel participated in the preparation and tests of the basic monolithic linings.Translated from Ogneupory, No. 8, pp. 1–4, August, 1989.  相似文献   

13.
国外生物降解聚合物的种类及主要组分   总被引:3,自引:0,他引:3  
据1996~1998年国外有关文献的汇集,由美,日,德等国主要研制,生产的生物降解聚合物种类为:1,单一型生物降解聚合物;(1)合成酯(酸)类;(2)淀粉基材料;(3)天然高分子材料;2、复合型生物降解聚合物;(1)不同种类的烃基互聚物;(2)烃酯(酸)/聚酯(3)脂肪族聚酯/芳香族聚酯共聚物;(3)淀粉基复合型,(5)光/生物降解聚合物;3、可生物降解水溶性聚合物。  相似文献   

14.
Book Reviews     
Physico-Chemical Basis of Formation of Non-Woven Materials, V. 6. Tikhomirov, Legkaya lndustriya Publ. Moscow 1969. 328 pp. Rub. 2.29.

ADHESIVES FOR METALS. THEORY AND TECHNOLOGY, Nicholas J. DeLollis. Industrial Press Inc., New York 1970. 230 pp. $15.00.  相似文献   

15.
针对纺织品上可能存在的九种致癌染料(C.I.酸性红26、C.I.分散橙11、C.I.分散黄3、C.I.分散蓝1、C.I.直接蓝6、C.I.直接黑38、C.I.直接红28、C.I.碱性红9、C.I.碱性紫14),本文研究并比较了不同剥色工艺对不同致癌染料剥色效果的影响.并提出选用加入尿素的甲醇作为剥色剂,使用超声功率为100W的超声波在70℃处理30分钟可以获得比较理想的剥色效果.  相似文献   

16.
《Fuel》1987,66(7):921-924
The oxidation of Illinois No. 6 coal proceeds readily with ruthenium(VIII) to provide a mixture of aliphatic and aromatic carboxylic acids. The acids were converted into their methyl esters for analysis by g.c.-m.s. and g.c.-FT-i.r. spectroscopy. Mono-, di-, tri- and tetracarboxylic acids are the principal products of the oxidation of this bituminous coal. The g.c.-FT-i.r. approach has enabled the detection of several different lactones that have not been observed previously. The results imply that cyclic ethers are present in low abundance in Illinois coals.  相似文献   

17.
Upgraded coal-derived liquids obtained from catalytic hydroprocessing of SRC-11 and H-coal syncrudes have been studied by i.r., p.m.r., g.c.-m.s., and silica gel chromatography. With increase in residence time, nitrogen, oxygen and aromatics decrease, while naphthenes increase substantially. All the upgraded liquids show low viscosity at 298 K (1.3–1.4 mN s m?2), even though saturate and aromatic fractions varied with processing severity. In the aromatic-1 fraction, 1 -ring aromatics increase, and 3-ring aromatics decrease, with increase in severity of hydroprocessing. G.c.-m.s. analyses indicate a marked qualitative similarity for saturate and aromatic fractions irrespective of syncrude source. Only the heavier end of the aromatic-1 fraction is noticeably different. Tentative identifications based on m.s. and g.c. retention times are made for most of the significant components. 600 M Hz p.m.r. spectra of the upgraded SRC-11 and H-coal liquids appear identical, but the n.m.r. difference technique revealed slight differences between the two liquids in concentrations of certain species.  相似文献   

18.
Magic-angle 13C n.m.r. spectra have been obtained for a series of vitrinite concentrates. Proper modification of the cross-polarization pulse sequence allows separation of protonated and nonprotonated carbon resonances. This technique is used to determine the relative fraction of nonprotonated aromatic carbons for each of the vitrinites, a parameter observed to decrease with increasing rank. Another parameter, related to the aromatic hydrogen content, is also calculated from these data and the results correlate with those from Fourier transform i.r. spectroscopy. The methods used for analysis of the vitrinite concentrates were then applied to the low-temperature oxidation of coal. The fractional aromaticity as determined by n.m.r. increases with longer oxidation times, indicating preferential attack on aliphatic structures. Here the FT-i.r. results are in quantitative agreement with those from n.m.r. Finally, the advantages of using various pulse sequences to extend the range of magic-angle n.m.r. and of combining FT-i.r. and n.m.r. results are discussed in the context of their potential for coal science.  相似文献   

19.
Conclusions New structural materials (single crystals obtained from partially stabilized zirconium dioxide) were studied. It was established that their physical and mechanical properties are certainly comparable to those of the other structural materials. We obtained new information regarding the mechanical behavior of the single crystals of zirconium dioxide that would facilitate further development of the technology of these materials and guide the studies on the mechanisms of their resistance to mechanical forces under different loading conditions.Translated from Ogneupory, No. 8, pp. 14–17, 1991.The authors wish to thank V. I. Aleksandrov, M. A. Vishnyakov, Yu. K. Voron'ko, and V. F. Kalabukhov for participating in the research work concerning crystal growth and V. I. Galenko, A. V. Drozdov, A. V. Cheboryukov, and A. I. Fesenko for carrying out mechanical testing.  相似文献   

20.
N.M.R. and U.V.-VIS Spectroscopic Investigations on Push-pull Butadienes 13C-n.m.r., d-n.m.r. and u.v.-vis spectroscopical data show that the push-pull character of the investigated butadienes is lowered by substitution at the carbon atom in 3-position of the butadiene chain.  相似文献   

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