Search

This study aims to solve the freezing problem of the 5 mm water layer remaining in the upper water chamber after elf-weight drainage of the tube and fin heat exchanger in the low-temperature wind tunnel under low-temperature operating conditions. Under the conditions that the hot air temperature inside and outside the tube are 10-70 °C and the inlet air speed s 2.78-10.56 m/s, two types of tube (elliptical tube and aluminum flat tube) and fin heat exchangers are tested and studied or drying the water layer remaining in the upper water chamber after self-weight drainage. The influence of the hot air inside and hot air outside the tube drying methods on the drying rate of the two heat exchangers are compared and analyzed. The results show that: the drying rate of aluminum flat tube heat exchanger is faster, so as the hot air outside the tube drying method; the heat exchanger drying time decrease with the increase of the inlet air speed and the drying time saves 50.75% at he inlet air speed of 10.56 m/s compared to 2.78 m/s. The empirical relationship equation for the drying rate was fitted by he experimental data, and the average error between the fitted results and the experimental measurements was less than 6.1%, which has a good prediction capability for the hot air drying rate of the tube-fin heat exchanger in the low-temperature wind tunnel. [ABSTRACT FROM AUTHOR]

In order to study and analyze the causes of perforation failure in 3003 aluminum tubes， used in automobile air conditioning， the reasons for surface perforation defects in these tubes were investigated.This investigation involved macro-morphology analysis，chemical composition analysis， scanning electron microscope micro-morphology analysis and energy spectrum analysis.Results showed that nonmetallic inclusions on the surfaces of the 3003 aluminum tubes damaged the integrity and continuity of these surfaces.This issue prevented the formation of a dense oxide film at the inclusion sites.Under the combined influence of the strongly corrosive elements chlorine (Cl) and sulfur (S)， pitting and perforation failures occurred in the 3003 aluminum tubes.It was suggested that the addition of refining agents should be carefully controlled during the melting process of the 3003 alloy.Additionally， improvements in the filtering of inclusions in the aluminum liquid， as well as enhancements in the surface cleanliness and storage environment of the aluminum tubes， were recommended.These research findings could provide a certain reference for the manufacturing of 3003 aluminum tubes.

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Casting tubes of 7055 aluminum alloy were prepared by the vacuumed centrifugal casting technology. The cooling rate of the casting was changed by the addition of the tundish and the corresponding microstructure and mechanical properties of the alloys were studied. The results show that the microstructure of the casting tube sample with the slow cooling rate(Casting tube 1#) is unevenly distributed. The grains change from the equiaxed grains to the coarse dendritic ones along the solidification direction of the cross-section plane， and some second phases are distributed at the grain boundaries. However， the microstructure of the casting tube sample with the fast cooling rate(Casting tube 2#)consists of the fine equiaxed grains and a small amount of second phases. After homogenization process， the amount of second phases along the solidification direction in both samples increase gradually， and the second phases of Casting tube 1# is greater， while the hardness increment and the tensile properties of Casting tube 2# is higher. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of Beijing Institute of Technology is the property of Beijing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)