A novel approach for measuring bubbles uniformity and mixing efficiency in a direct contact heat exchanger
A novel approach for measuring bubbles uniformity and mixing efficiency in a direct contact heat exchanger
复制标题
测量直接接触式热交换器中气泡均匀性和混合效率的新方法
DOI：
10.1016/j.energy.2015.10.126
复制
发表时间：
2015
期刊：
影响因子：
9
通讯作者：
Huang Junwei
中科院分区：
文献类型：
--
作者：
Fei Yu;Xiao Qingtai;Xu Jianxin;Pan Jianxin;Wang Shibo;Wang Hua;Huang Junwei
本文提出了一种基于均匀设计的直接接触式换热器中气泡均匀性和混合时间的直接评价方法。气泡运动的演变实验跟踪使用的成像技术，在Matlab软件中处理，以获得局部气泡浓度。一组泡沫的局部差异似乎是一个有用的概念来衡量理论和经验分布之间的差异。UC（均匀性系数）与差异相关，导致一个有用的参数来表征混合物的均匀性和混合时间。为了确定表达式、迭代步骤和像素对测量的影响，研究了UC响应帧的演化。将UC法获得的混合时间和均匀度与Betti数法获得的数据进行比较。讨论了局部均匀和全局均匀（具有相同的Betti数）之间的模拟和实验，并给出了示例说明。结果表明，UC方法成功地导出了混合过程的时空特征。UC曲线为研究和比较不同体系的混合效率提供了新的视角，具有高度的可靠性，可以获得准确的混合信息。
This paper presents a straightforward method for assessing the uniformity and mixing time of bubbles based on uniform design in a direct contact heat exchanger. The evolution of bubbles movement is experimentally tracked using an imaging technique that is processed in the Matlab software to obtain the local bubble concentration. The local discrepancy of a set of bubbles seems to be a useful concept to measure the difference between theory and empirical distribution. The UC (uniformity coefficient) is associated with a discrepancy, leading to a useful parameter to characterise the mixture homogeneity and mixing time. To determine the impact of expressions, iteration steps and pixels on the measurement, evolution of UC response frames are investigated. The mixing time and uniformity obtained by UC method were compared with data obtained by Betti numbers method. The simulations and experiments between local and global uniform (with the same Betti numbers) are discussed and examples are given for illustration. The results show that the space-time features of the mixing process have been successfully derived by UC method. The UC curves bring new insights to study and compare mixing efficiency of different systems, which has a high degree of reliability, and can yield accurate mixing information.