换热管的新型协同角方法及数值模拟

发布时间：2018-03-06 11:22

本文选题：场协同原理　切入点：无量纲参数N_0　出处：《湘潭大学》2016年硕士论文　论文类型：学位论文

【摘要】：能源在如今的生活及社会发展中起着举足轻重的作用,所以能源对于人们的意义非常重大,但是地球资源日益减少,所以对于提高能源利用率的要求迫在眉睫.强化换热技术为了现代工业的需求,不断缩小换热设备的重量和体积,并且仍然可以使换热设备的效率大大提高,故在工业界以及科技节备受重视.但是已经广泛应用的受迫流动强化传热技术都存在强化换热的同时功耗增加更多的问题.本文为了寻找较好的强化换热管型,对圆管、椭圆管和滴型管三种不同管型的管外空气侧的流动进行数值模拟.比较三种强化换热管的换热性能的优劣,得出滴型管的流动与传热综合性能较优,椭圆管次之,圆管较差的结论,并利用场协同原理对模拟结果进行分析,验证了模拟结果的正确性.根据换热性能分析标准定义了新的换热与流动评价标准,无量纲参数N0来综合评价换热表面的强化传热效果,得出和场协同原理相似的结论.并对清华大学提出的交叉缩放椭圆管进行数值模拟,改变交叉缩放椭圆管的特定尺寸参数,以传统评价标准PEC,在交叉缩放椭圆管之间进行横向对比,确定换热最优尺寸.以场协同原理为指导思想,分析纵向涡对速度与温度梯度协同角的影响,推导出新型的协同角表达式.从温度场、速度场和压力场三个方面出发分析交叉缩放椭圆管换热机理,总结换热特点,指出交叉缩放椭圆管换热效果良好的原因.在本文中,用场协同原理对数值模拟中出现的现象进行理论分析.从数值模拟结果和理论分析两方面出发进行比较,得出合理结论.
[Abstract]:Energy plays an important role in today's life and social development, so energy is of great significance to people, but the earth's resources are decreasing day by day. So it is urgent to improve the energy efficiency. For the sake of the demand of modern industry, the weight and volume of heat exchanger can be reduced continuously, and the efficiency of heat exchanger can be greatly improved. Therefore, great attention has been paid to the industry and science and technology section. However, the forced flow enhancement heat transfer technology, which has been widely used, has the problem of enhancing heat transfer and increasing power consumption. In order to find a better type of enhanced heat transfer pipe, this paper deals with the circular tube. Numerical simulation of the flow around the air side of the tube with three different types of elliptical tube and droplet tube is carried out. By comparing the heat transfer performance of the three enhanced heat transfer tubes, it is concluded that the flow and heat transfer performance of the droplet tube is better than that of the elliptical tube. The conclusion that the tube is worse and the simulation results are analyzed by using the field synergy principle, the correctness of the simulation results is verified. According to the heat transfer performance analysis standard, a new evaluation standard for heat transfer and flow is defined. The dimensionless parameter N0 is used to synthetically evaluate the heat transfer enhancement effect of the heat transfer surface, and the conclusion is similar to that of the field synergy principle. The numerical simulation of the cross scaled elliptic tube proposed by Tsinghua University is carried out to change the specific dimension parameters of the cross scaled elliptic tube. Based on the traditional evaluation standard PECs, the transverse comparison between cross-scaled elliptical tubes is carried out to determine the optimal size of heat transfer. Based on the principle of field synergy, the influence of longitudinal vortices on the synergistic angle between velocity and temperature gradient is analyzed. In this paper, the heat transfer mechanism of cross scaled elliptic tube is analyzed from three aspects: temperature field, velocity field and pressure field. The heat transfer characteristics of cross scaled elliptical tube are summarized, and the reason for the good heat transfer effect of cross scaled elliptic tube is pointed out. The phenomena in numerical simulation are analyzed theoretically by using the principle of field cooperation, and the reasonable conclusions are drawn by comparing the results of numerical simulation and theoretical analysis.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK172

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