涟漪纹管和人字形微翅片管蒸发实验研究

发布时间：2018-09-12 14:32

【摘要】：强化传热技术在提高能源效率方面起着重要的作用,该方面的研究也是历久弥新。各种类型的传热强化管相继得到开发,并广泛应用工业生产活动中。一种新型的强化管涟漪纹管(1EHT管)通过其特殊的表面结构能够增加汽化核心数、增强流动的湍流度、干扰边界层、制造流动分离、产生二次流等。本文主要完成了以下几方面的工作：首先对国内外单管两相流换热的研究,进行了文献搜集和汇总,并对其研究方法和结论进行了整理；利用高精度换热实验台,对涟漪纹管(1EHT tube)、人字形微翅片管(herringbone tube)和光管(smooth tube)进行了低质量流速条件下的蒸发换热实验研究；对实验结果进行分析,得到适用于管内蒸发的换热和压降关联式。具体的研究方法是对涟漪纹管、人字形微翅片管和光管进行单相及蒸发实验研究,使用的制冷剂工质为R410A。蒸发实验工况如下：质量流量在10kg/h～45kg/h之间,蒸发饱和温度为279K,进口干度为0.1,管外蒸发时出口干度为0.8、0.6和0.4,管内蒸发时出口干度为0.9。结果表明,管外蒸发时人字形微翅片管换热系数最高,压降也最大,其次为涟漪纹管；出口干度0.6时,所有管型的换热系数都达到峰值；管内蒸发时涟漪纹管的换热性能最好,压降增加较小；管内蒸发流型为波状的分层流,修正过的换热和压降预测公式的预测误差在±20%以内。
[Abstract]:Enhanced heat transfer technology plays an important role in improving energy efficiency. Various types of heat transfer enhancement tubes have been developed and widely used in industrial production. A new type of reinforced tube ripple tube (1EHT tube) can increase the number of vaporization core, enhance the turbulent degree of flow, interfere with boundary layer, make flow separation and produce secondary flow through its special surface structure. The main work of this paper is as follows: firstly, the research on heat transfer of single-tube two-phase flow at home and abroad has been collected and summarized, and its research methods and conclusions have been sorted out. The evaporative heat transfer of ripple tube (1EHT tube), herringbone finned tube (herringbone tube) and smooth tube (smooth tube) at low mass flow rate was studied, and the heat transfer and pressure drop correlation formula suitable for evaporation in the tube were obtained by analyzing the experimental results. The specific research method is to study the single phase and evaporation of ripple tube, herringbone micro finned tube and light tube. The refrigerant working medium is R410A. The experimental conditions are as follows: the mass flow rate is between 10kg/h~45kg/h, the evaporation saturation temperature is 279K, the inlet dryness is 0.1, the outlet dryness is 0.80.6 and 0.4when evaporation is outside the tube, and the outlet dryness is 0.9when evaporating inside the pipe. The results show that the heat transfer coefficient of the herringbone micro-finned tube is the highest, the pressure drop is the largest, and the ripple tube is the second, when the outlet dryness is 0.6, the heat transfer coefficient of all the tubes reaches the peak value, and the heat transfer performance of the ripple tube is the best when the pipe evaporates. The change of pressure drop is small, and the prediction error of modified prediction formula of heat transfer and pressure drop is less than 卤20%.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK124

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