THE MECHANISM OF AUGMENTATION HEAT TRANSFER AT HIGH PERFORMANCE BOILING SURFACES

1.多孔表面基本特性的测试(1)氮化铝溅射表面实验对氮化铝溅射表面与R113、R12和N_2三种试验流体的池核沸腾进行了实验，并与文献[1]的分析结果进行了比较。(2)青铜颗粒的烧结层在为优化结构设计的实验表面上进行了沸腾液体R12和N_2的实验，并根据实验和分析的结果对其增强特性进行了讨论。(3)铝等离子体展宽表面用等离子体展宽的方法制作了铝颗粒涂层表面。这种颗粒直径为70微米的多孔表面在沸腾液态N_2时非常有效。在现有工艺中，确保良好的空隙空间和制备一层大颗粒在技术上是困难的。对多孔层的传热过程进行了分析，提出了传热关联式。讨论了烧结层的颗粒直径和厚度对沸腾换热的影响。以燃尽热流密度为标度因子，提出了一种强化性能模型。

1. Test on basic characteristic at porous surfaces(1) ALN spattered surfaceThe experiment has performed on pool nucleate boiling from ALN spattered sur faces to three test fluids of R113, R12 and N_2, then the results were compared with the analysis proposed earlier [1]. The particle diameter of this porous layer, which can be applied at this moment, is so small that the performance is unsatisfactory.(2) Sintered layer of bronze particleAn experimental surface designed for an optimum structure was tested for boiling liquids R12 and N_2. Discussions of the augmentation characteristics have been made based on the results of experimentation and analysis.(3) Aluminum plasma splayed surfaceAluminum particles coated surface was made with plasma splay method. This porous surface, of particle diameter 70[mum], was highly effective in boiling liquid N_2. Ensuring a well defined void space and preparing a layer of large particles are difficult technically at the process available.2. Analysis of the heat transfer process at the porous layer and proposal of heat transfer correlationThe effects of the particle diameter and the thickness of the sintered layer on nucleate boiling heat transfer are discussed. Making use of the burnout heat flux as a scaling factor, we have proposed a model of augmentation performance.