摘要当前,科学技术的迅速发展和世界能源的日益紧缺要求我们对能源的利用要 更加合理,即提高能源的利用率。而强化传热,尤其是强化沸腾换热更是被看作 一种重要的有效途径。本文主要设计了研究泡沫金属强化沸腾换热的试验装置, 并给出了具体的试验方案,分析预测了相应的试验结果,最后对试验误差的进行 了估算。81563
在试验装置的具体设计中,首先对加热器和蒸发器进行了设计。热源和蒸发 器的设计实现了一体化,并且设计了直径达 30mm 的铜柱表面作为传热表面,这 样省去辅助加热器的设计。其次,根据蒸发器所产生的热量自主设计了冷凝器, 并且将冷却系统和蒸发器做成了一个封闭的循环系统。这样省去了试验过程中需 随时充液的繁琐。在冷凝管的设计中,为管长留了充足的余量,确保了冷却效率 可以满足试验的需求。最后,设计并校核了连接蒸发器和冷凝器的蒸汽管和冷凝 管。
试验方案主要分两个方面,一是改变沸腾传热表面的结构,二是改变沸腾工 质的种类,分别研究它们对系统沸腾换热性能的影响。最后可以通过对试验测得 的数据进行处理,并且对相应的图表进行分析,整理得出试验结论。
对于试验误差的分析,本文主要考虑了热流密度的误差以及温度的测量误差。 通过极限误差分析方法,最后综合计算求得试验误差在 9%左右。
毕业论文关键字:泡沫金属;强化沸腾传热;热流密度;换热系数
Abstract At present, the rapid development of science and technology and the increasing shortage of energy world's requires us to use energy more rationally, it aims to improve the energy efficiency。 The enhancement of heat transfer, especially boiling heat has been seen as an important and effective way。 This paper has designed test apparatus, which is to study to strengthen the of metal foam boiling heat transfer, given a specific protocol, analysised and forecasted of the corresponding results ,at last test error was estimated。
During the design of the test apparatus ,at first ,design the heater and evaporator, and make the heat and evaporator to achieve the integration。 Design a diameter of 30mm copper pillar surface as a heat transfer surface, so eliminating the need for auxiliary heater design。 Secondly, according to the heat generated by the evaporator independent design of the condenser。 Make the evaporator and cooling system consisted a closed loop system。 This eliminates the need to feel at any time during the test。 In the condenser design, the tube length leaving a sufficient margin to ensure that the cooling efficiency to meet the test requirements。 Finally, the design of the connector and check the evaporator and condenser tubes and steam condenser。
Test program is pided into two aspects, one is to change the type of working fluid boiling, another is to change the structure of boiling heat transfer surface。 And then study their boiling heat transfer performance of the system。 Finally, we can test the measured data processing, analysised the appropriate chart, and collated test conclusions。 Then strengthen the system eventually mastered boiling heat transfer method。 In the third chapter of this paper, experimental predictions has been set up。
For the error analysis of experimental, the paper mainly considered the source of error test is the error of the heat flux and temperature。 By simulating the evaporator, the trial heat leakage rate is 2%。 The final consolidated calculable experimental error of the test is about 9%。
Keywords: foam metal; enhancement of boiling heat transfer; heat flux; heat transfer coefficient;
第一章 绪论 1
1。1 课题的背景及研究意义