2003 Fiscal Year Final Research Report Summary
Dynamics of surface waves on films falling down horizontal tubes and associated gas absorption
| Project/Area Number |
14550191
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | University of the Ryukyus |
|---|
Principal Investigator |
NOSOKO Takehiro University of the Ryukyus, Faculty of Engineering, Dept. Mechanical Systems Eng., Professor, 工学部, 助教授 (80183903)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIYARA Akio Saga University, Faculty of Science and Engineering, Dept.Mechanical and Systems Eng., Professor, 理工学部, 教授 (80219823)
GIMA Satoru University of the Ryukyus, Faculty of Engineering, Dept. Mechanical Systems Eng., Associate Professor, 工学部, 助教授 (60274883)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Keywords | Liquid film / Gas absorption / Horizontal tubes / Surface wave / Mass transfer / Mass diffusion |
|---|
| Research Abstract |
A gas absorber, in which liquid films fall down horizontal tubes and absorb surrounding gas, was experimentally and theoretically analyzed, and the analytical results were compared with those of a vertical-tube gas absorber.Smooth film falling down horizontal tubes and the associated gas absorption were theoretically analyzed, assuming that a concentration boundary layer starts at the top of tube and develops along the smooth surface to its bottom.When the tube spacings are smaller than the capillary constant, liquid forms sheets between tubes and continuously flows in them, and forms nearly uniform films falling down all tubes.With wider tube spacings, liquid drips off each tube and causes the large-amplitude waves which rapidly spread on the film covering the lower tube.The drip makes the films flow more unevenly on lower tubes.The drip-caused waves enhance, the associated gas absorption by 50% or more, compared with the sheet flow between tubes.Imposing periodical perturbations on feeding flow to the top tube enhances the gas absorption of films with the sheet flow between tubes by 〜20% at the Reynolds number Re<30.Rayleigh instability was observed on films covering 6 mm diameter tubes and enhanced the gas absorption. The film flow on horizontal tubes, in which the drip completely renews concentration boundary layers and a new boundary layer starts at the top of lower tube, has larger gas absorption rate than the films falling down vertical tubes on which roll waves greatly enhance the gas absorption.
|
Research Products
(6 results)
