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Development And Application Of Movable Erosion Wind Tunnel

Posted on:2005-04-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:J F RongFull Text:PDF
GTID:1100360122488847Subject:Agricultural mechanization project
Abstract/Summary:PDF Full Text Request
In the recent decades, sandstorm in our country is rampant increasingly, which has caused serious harm to the national economy construction and the people's daily lives. Analyzing the sandstorm, the experts and scholars in our country have recognized that, the main reason of sandstorm happens is the increasing expansion of desertification land and the primary sector forming desertification of land is the soil wind erosion.The experiences of controlling sandstorm in the world indicate that, promoting conservation tillage can effectively control the raising of dust on soil surface, prevent soil from wind erosion, restrain the trend of land desertification, and ultimately, realize the purpose of controlling sandstorm. China Agricultural University established an experiment plots in high land of Fengning country, Hebei province and observed the natural wind erosion. It indicated that, compared with traditional tillage - plowing up the soil in autumn, conservation tillage can reduce 77% of soil wind erosion. It is necessary to research systematically and comprehensively on farmland wind erosion in order to study further about the effects and mechanism of conservation tillage and to explore the measures of preventing soil wind erosion. However, in observing natural wind erosion, because of the limitation of several factors, such as time, wind power, and the surface of land, it is difficult to take systematic and deeper research, especially to complete the research on the regularity of soil wind erosion in a short period. So, it is significant from present and long-term benefits to design and make movable wind erosion tunnel, and to apply it as a tool to carry out research on protective cultivation, diminution of soil wind erosion, reduction through conservation tillage. Therefore, this article has carried on the following work:1 .Designed and made a movable wind erosion tunnel drove by tractor firstly in our country. The wind speed range of the tunnel is from 2 m/s to 28 m/s and the speed can be adjusted continuously. The total length of the wind tunnel is 11 m. The experimental sector is 6 m in length and it is rectangle in section without bottom. The height of the segment is 1.0 m and the width is 0.8 m. The result that the experimental sector has stable wind flow and the characteristic of wind speed which makes the wind speed more consistent with real condition of the surface of land has the rule of logarithm, which is matched with the requirement of wind erosion experiment. The wind erosion tunnel has the following advantages. (1) The designed wind tunnel has the separate structure. Not only every sector of the tunnel can be separated but also the experiment sector can separate to 9 steel boards. All of the separate tunnel can be transferred and transported with a Beijing 1041 truck. (2) Using tractor as power, makes it mobile and agile, and, the tractor can be used to do another work if it is not used to drive the tunnel. The tractor with simple hoist implement can assemble the wind tunnel by use of the oil cylinder of tractor itself without another special implement.2.By analyzing, the reason of the low efficiency of collecting dust sample by using sand collector is the dissatisfaction of the equal dynamic function. Therefore, the following two aspects are studied: (1)Analyzed how it affects toward the principle of the equal dynamic with the change of the air vent area of the sand collector. The result indicates that the function of the equal dynamic is notably affected by the size of the air vent area. (2) Analyzed the effect toward the principle of the equal dynamic function in respect of the design of the air vent of the sand collector, it indicates that the satisfaction toward the equal dynamic function easier to reach if the position of the air vent is on top of the sand collection meter or if the height of the sand entry of the sand collector is reduced instead of the flank of it. Above study is of the first time in our country.3.Designed a slitting sampling device used by the movab...
Keywords/Search Tags:movable wind erosion tunnel, sand collection of wind tunnel, sandstorm, soil wind erosion, conservation tillage
PDF Full Text Request
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