基于Fluent模拟的空压机散热设计(2)
确定优化设计方案后，使用fluent软件对新方案进行udf模拟，通过动态模拟得知，优化方案能更好的满足螺杆空压机内部的散热需求，能较大幅度地提高了螺杆空压机的安全性，从而确定本方案为螺杆空压机散热设计的最终方案。
关键词： 螺杆空压机；数值模拟；散热；UDF；fluent
Air Compressor thermal design based on fluent simulation
Abstract: At present, the scale of compressors in the maket is in rapid growth in our country every year. With the continuous development of the air compressor industry, enterprises are entering into and favouring the air compressor industry in an increasing number. The reason why the development of the air compressor is so rapid is that the air has good compressibility and elasticity. And the other reason is that the transportation system is simple and safe so that the air compressor is widely used in the industrial and mining enterprises and the main function of the air compressor is the power source of pneumatic equipments and the material handling. Especially under the coral mine with inflammable and explosive dust and gas, the air compressor is better than the electric power in security and reliability.
However, due to the low compression efficiency of air compression device, the pressure potential energy is formed by compressed air only about 20% of the input energy and the other 80% of input energy by the air compressor which is emitted to the ambient air in the form of the thermal energy. When the compressed air is 0.8MPa, the theoretical temperature of air will reach 263℃. It is clear that the air compressor will produce a lot of heat in the running process. Therefore, we must pay attention to the thermal design of the air compressor, or it is likely to cause accidents.
This paper used the method of numerical simulation in the running process of the screw compressor to do the simulation and research for the design of ventilation and heat dissipation in the compressor. The precondition of this design used Gambit software to establish the model of the air compressor and then it used fluent software to simulate internal temperature field of the air compressor. Fluent software is one of the CFD software in the engineering application. According to the characteristics of physics problems of each flow, it used numerical solution in computing speed, stability and accuracy suited to its optimum. The function of CFD software is calculation the flow field, heat transfer and chemical reactions. It also can shorten the design process, reduce the number of measuring tests in the laboratory and reduce the cost of product development.
The design of this study is 3 meters long, 2.5 meters wide, 1.5 meters high screw air compressor, with vent holes on each side of four size is 0.6 x 0.05 meters, inside the motor, bearings, air storage tank, operation table etc. Before the simulation by using FLUENT software, need to use the gambit software to establish the air compressor model. More convenient for the observation of the design changes, establish the air compressor model the ratio of 1:2. And then the related parameters of air compressor through the FLUENT software set, and the simulation of screw air compressor at the highest operating temperature conditions. After the original conditions that simulate internal screw air compressor temperature is too high, so the four schemes of air compressor internal heat. Four schemes are: increase the outlet quantity, increase the air outlet size, increasing the inlet area, increasing the inlet velocity.
Scheme one: study on the screw air compressor of the 4 air outlet has been increased to 9 air outlet of the heat. the simulation results show that, the increase in the number of outlets will reduce air compressor internal temperature, but the temperature is not very clear, so the scheme does not meet the cooling requirements.
Scheme two: study on the screw air compressor outlet size increases from 6m×0.05m to 0.8m×0.1M, through the simulation results that air compressor internal temperature decreased, but does not satisfy the cooling needs.
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