射流式真空发生器真空度特性的研究

发布时间：2018-05-04 07:56

本文选题：真空度特性 + 最大真空度　；参考：《大连海事大学》2017年硕士论文

【摘要】：以射流式真空发生器为真空发生装置的真空吸附系统作为一种重要的搬运技术,使气动技术应用的领域越来越广泛。但是射流式真空发生器存在一个共同的规律,真空度在供给压力0.45 MPa达到最大,超过0.45 MPa时,真空度会出现下降;而且在正常工作过程中必须持续定量供气,空气消耗量很大。因此,本文针对此问题分析真空度下降的原因,并通过仿真获得影响真空度的结构参数,使最大真空度在更低供给压力下达到最大值,从而节省空气的消耗。由于真空发生器是根据拉瓦尔喷管的原理进行工作的,首先,本文针对拉瓦尔喷管的工作原理分析其喷管内几种流动状态,研究不同上游与下游压力比值喷管内的流动状态。利用fluent对其进行数值模拟仿真,仿真结果表示:改变拉瓦尔喷管的收缩角或扩张角,其出口速度基本不变;但改变喷管出口面积与喉部面积比值,喷管出口速度发生显著的变化,因此面积比是影响拉瓦尔喷管加速的主要因素,喷管出口速度是由面积比值唯一确定的。由通过拉瓦尔喷管空气消耗量公式可知,空气消耗量与供给压力成正比,因此可通过降低供给压力的大小来减小空气的消耗,从而实现节能。其次,利用fluent对真空发生器整个内部流场数值模拟仿真,分析了真空度下降的原因以及在不同的参数下真空发生器真空度曲线的变化,探讨了真空发生器参数对最大真空度下降点以及峰值的影响。最后,采用3D打印技术加工设计不同结构参数的真空发生器,搭建试验台并通过试验研究参数的变化对其性能的影响。试验结果表明:减小扩张管直径或面积比值的大小,可使真空度在更低压力达到最大值。以喷嘴直径为1mm的为例,在出口直径为1.8 mm、扩张管直径为2.2 mm,取得最大真空度的供气压力为0.3 MPa,最大真空度为86 kPa,降低了取得最大真空度的压力值,相当于减小了空气消耗量。
[Abstract]:The vacuum adsorption system with a jet vacuum generator as a vacuum generator is an important transportation technology, which makes the application of pneumatic technology more and more widely. But there is a common law in the jet vacuum generator. The vacuum degree will decrease when the supply pressure is 0.45 MPa and the vacuum is over 0.45 MPa. In the normal working process, the quantity of air supply must be sustained and the air consumption is very large. Therefore, this paper analyzes the cause of the decline of the vacuum degree, and obtains the structural parameters affecting the vacuum degree by simulation, so that the maximum vacuum is reached to the maximum under the lower supply pressure, thus saving the air consumption. As the vacuum generator is the root, the vacuum generator is the root. According to the principle of Lawal nozzle, first of all, this paper analyzes several flow states of the nozzle in the nozzle of the Lawal nozzle and studies the flow state within the ratio of the pressure ratio between the upstream and downstream. The numerical simulation of the nozzle is simulated by fluent, and the result is that the contraction angle or expansion of the Lawal nozzle is changed. The outlet speed of the nozzle is basically the same, but the velocity of nozzle exit is greatly changed by changing the ratio of the nozzle area to the throat area, so the area ratio is the main factor affecting the acceleration of the Lawal nozzle. The outlet velocity of the nozzle is determined only by the ratio of the area. It is known that the air consumption through the air consumption formula of the Lawal nozzle can be known. The quantity is proportional to the supply pressure, so the air consumption can be reduced by reducing the size of the supply pressure to achieve energy saving. Secondly, the fluent is used to simulate the whole internal flow field of the vacuum generator, and the reasons for the decrease of the vacuum degree and the change of the vacuum degree curve of the vacuum generator under different parameters are discussed. The effect of the parameters of the vacuum generator on the maximum vacuum drop point and the peak value. Finally, the 3D printing technology is used to process the vacuum generator with different structural parameters. The test bench is built and the influence of the change of the parameters on its performance is studied. The test results show that the size of the diameter or area ratio of the Jian Xiaokuo tube can make the vacuum degree. In the case of the lower pressure, the diameter of the nozzle is 1mm, the diameter of the outlet is 1.8 mm, the diameter of the dilated tube is 2.2 mm, the gas supply pressure of the maximum vacuum is 0.3 MPa and the maximum vacuum is 86 kPa, which reduces the maximum vacuum pressure value, which is equivalent to reducing the air consumption.

【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB75

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