Floating Nursery Gas On Tobacco Suction Seeder Study

In tobacco production, the nursery is an important part of the production of flue-cured tobacco, and flue-cured tobacco is to achieve high-quality seedling production. Now, floating technology has been widely applied to tobacco production, and the relevant planting mechanical research is to start growing.In Sichuan, Yunnan, Guizhou and other places, tobacco is cultivated in mountainous areas mostly. The power source that the seeding machines in the market require is not readily available in these areas. Based on this background, this article first studies on the nozzle flow field of air-suction seeder. And the use of manual vacuum pump can supply the vacuum to pick up seeds, which resolved the problem of available source of power is not readily in the mountains area.Aimed at air-suction seeder, the Paper does the following main aspects:1. In reading the relevant literature, we find that adsorption properties of the nozzle in recent study are to establish multi-nozzle flow field in the assumptions form of cone or sphere. Chapter II of this article verify these two assumptions by using FloWorks fluid simulation software carry out simulation analysis to three different shape of the nozzle flow field. First of all, gives detailed description on how to use the COSMOS / FloWorks plug-ins embed in SolidWorks software for modeling, computational domain defining and boundary conditions adding. Then use FloWorks carry out the simulation of the three types' model of nozzle flow field, the results show a variety of functions to deal with the specific form of the external flow field. Finally, receives the conclusions of different shape of the nozzle flow field generated by different forms.2. By the conclusions of the second chapter, the paper assumes velocity surface of the nozzle outflow field to be specific cone or sphere. On the assumption above, the third chapter mechanical analyses the critical adsorption location right below the nozzle, and obtains the critical adsorption distance, the critical adsorption speed and other related formulas like about the critical adsorption force. And then analyses the condition when the tobacco coating seed oblique below the nozzle critical adsorption position through theoretical calculations, and obtains the adsorption speed and the relevant formula of adsorption distance. Finally, two cases of seeds right below the nozzle and oblique below the nozzle will be contrast, and we find out that when the oblique angle between seeds and nozzle increases the threshold requirements of absorption speed will also increase.3. For verify the formula obtained through theoretical calculations in last chapter, Chapter IV of this article used the plug-ins of COSMOS/FloWorks to simulate the model with seeds ,and measured the distance of critical absorption. Firstly, in this chapter, using the velocity of critical absorption obtained by the formula about velocity of critical absorption, and assuming that when velocity isolines created by the velocity of critical absorption is tangential with the top of seed, the seed is in the location of critical adsorption; based on the assumption, simulating the situation that seed is in the bottom of nozzle as well as the oblique of nozzle in free-space, measuring the distance of critical adsorption; and simulating the situation that seed is on the disk(including types of non-porous disk and disk-hole species),measuring the distance of critical adsorption in disk; finally comparing the data obtained to get some conclusions.4. The chapter V of this article mainly put up the test-bed, measuring the distance of critical adsorption in the situation that seed is in the below of nozzle and comparing the distance with that got through the theoretical calculations. Using the cylindrical nozzle of 1.4mm diameter and number 87 seed Bunyan, the vacuum -20kPa, measuring and comparing the distance of critical adsorption to verify the correctness of assumptions in last chapter and methods using to measuring the distance of critical adsorption. Finally doing test in different vacuum to get distance of critical adsorption, and making the relationship of all kinds of distance data clear.