High Density Array of Tubes in Horizontal Tube-Bundle Evaporator

卧式管束蒸发器中的高密度管阵列

基本信息

批准号：
05555067
负责人：
FUJITA Yasunobu
金额：
$ 4.42万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05555067/
关键词：
Boiling in Tube Bundle Nucleate Boiling In-line Array Staggered Array Critical Heat Flux 高密度管配列

项目摘要

An experimental study on nucleate boiling heat transfer was performed to investigate various effects on heat transfer characteristics in horizontal tube bundle and to gain useful information for developing an evaporator with horizontal tubes more densely arrayd. Experiments were done for in-line and ataggered tube arrangement under the conditions of natural circulation and forced circulation of fluid within a tube bundle. Findings are as follows.(1) Compared with the performance of a single horizontal tube in pool boiling, heat transfer coefficient of tube bundle shows the same level at higher heat flux where nucleate boiling is fully established, while at lower heat flux the boiling heat transfer is highly enhanced in a bundle.(2) The above mentioned difference in performance between a single tube and a tube bundle is true for both bundles of in-line and staggered arrangement.(3) Under the condition of natural circulation a rise of heat transfer coefficient at lower heat flux is more enhanced as the location of tube is higher in a bundle.(4) In the case of forced circulation, heat transfer coefficient at lower heat flux increases with an increase of circulating flow velocity. Heat transfer coefficient increases vertically at first for lower tubes, then decreases for higher tubes.(5) As for an effect of tube pitch, a pitch to diameter ratio P/D of 1.5 shows better performance under the natural circulation, while a P/D of 1.3 is preferable for the forced circulation.

对核态沸腾传热进行了实验研究，以研究对水平管束传热特性的各种影响，并为开发水平管束更密集的蒸发器提供有用的信息。在管束内流体自然循环和强制循环条件下进行了直列式和交错式管布置实验。研究结果如下：(1)与单个水平管在池沸腾中的性能相比，管束的传热系数在较高热通量时表现出相同水平，充分建立核沸腾，而在较低热通量时，沸腾热完全建立。 (2) 上述单管与管束性能的差异对于直列式和交错布置的管束均成立。(3) 在自然循环条件下，较低热通量下的传热系数更加增强，因为(4)在强制循环情况下，较低热通量下的传热系数随着循环流速的增大而增大。 (5) 就管距的影响而言, 节径比 P/D 为 1.5 时, 自然循环下传热系数较好, 而 P/对于强制循环，D优选为1.3。