Knowledge Management System Of Guangzhou Institute of Energy Conversion, CAS
| 微通道中流动沸腾不稳定性及压降特性的研究 | |
| Alternative Title | Flow boiling instabilities and pressure drop characteristics in microchannel |
| 张炳雷 | |
| Thesis Advisor | 徐进良 |
| 2007-06-09 | |
| Degree Grantor | 中国科学院广州能源研究所 |
| Place of Conferral | 广州能源研究所 |
| Degree Name | 硕士 |
| Keyword | 不稳定性 压力降型脉动 流量漂移 微通道 压降特性 |
| Abstract | 本文以甲醇为工质，在不同进口温度、质量流速、热流密度和倾角下低高宽比矩形微通道中流动沸腾不稳定性和压降进行了实验研究。 在宽广的参数范围内发现存在两类不稳定性：流量漂移静态不稳定性和压力降型脉动动态不稳定性。分析发现由于实验段本身大长径比（L/d = 159.5）及实验段上游可压缩容积的存在，导致水动力曲线负斜率区压力降型脉动的发生。分析了进口温度、倾角、质量流量、热流密度等因素对不稳定性的影响，发现压力降型脉动的发生主要取决于质量流量、热流密度及进口温度三者的影响，得出了以热力学平衡质量含气率表示的脉动工况界限范围。 此外，对低高宽比微通道流动沸腾压降进行了实验研究，并分别采用均相模型和分相模型对通道压降进行了计算。对采用的六个公式进行了校验发现现有公式不能很好的预测本实验中微通道两相压降。提出了一个新的考虑了通道尺寸和质量流量影响的微通道两相流动压降计算公式，计算结果显示预测精度高于前面所采用的六个公式，平均相对误差仅为16.9％。 |
| Other Abstract | Flow boiling instabilities and pressure drop characteristics in a single microchannel with low aspect ratio were studied, taking account of the effects of inlet temperature，mass flux，heat flux , inclined angle using methanol as the working fluid. Two type instabilities were found over wide parameter ranges：flow excursion static instability and pressure-drop type oscillation. Due to the large ratio of the channel length to the hydraulic diameter and the upstream compressible volume，the pressure drop type oscillation occurs in the negative gradient region of the demand curve of pressure drops versus mass fluxes. The influences of the inlet temperature，inclined angle，mass flux and heat flux on the flow instability were analyzed. It is demonstrated that whether the pressure-drop type oscillation occurs or not depends on the inlet temperature，mass flux and heat flux. The range in which the pressure-drop type oscillation occurs is presented with the outlet mass quality as the control parameter. In addition , pressure drops of flow boiling in a single microchannel having low aspect ratio were studied . The present experimental data were compared with the predictions of the homogeneous flow model and separated flow model respectively. The comparisons with six correlations indicate that all the existing correlations failed to predict the two-phase flow pressure drop in the microchannel of this study . A new correlation to predict the two-phase flow pressure drop in microchannels was developed .It include the effect of the hydraulic diameter and the effect of mass flux on the two-phase flow pressure drop in microchannels .The new correlation developed in this study predicted the experimental data within a mean absolute error of 16.9%，which is more precision than the result from the six correlations used before. |
| Pages | 50 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.giec.ac.cn/handle/344007/3999 |
| Collection | 中国科学院广州能源研究所 |
| Recommended Citation GB/T 7714 | 张炳雷. 微通道中流动沸腾不稳定性及压降特性的研究[D]. 广州能源研究所. 中国科学院广州能源研究所,2007. |
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