Simulation of granulated droplet formation from thin film under the influence of an electric field and the effect of condensation and evaporation heat transfer on the transient droplet surface configuration
The granulation phenomenon that occurs on the surface of a liquid film flow upon applying an electric field verified the enhancing effect of heat transfer, for both condensation on a vertical tube and vertical falling evaporation. This granulation phenomenon is only generated on a thin liquid film. To clarify the heat transfer enhancing effect of the granulation phenomenon, the detailed motion and the surface configuration of a droplet need to be clarified. The granulation profile was numerically simulated and compared the calculating enhancement of the heat transfer with experiments in this paper. The calculation one generated droplet conducted in the critical wavelength, which was calculated upon assuming the electric field distribution of the thin liquid film. Initially assuming that the small disturbance profile on the thin liquid film, the droplet form on the thin liquid was solved b successively calculating fluid-dynamic equations and pressure balance. The droplet form without exchanged heat was converged to a steady parabolic droplet surface profile. Moreover, the successive calculation by adding the effect of the condensation or the evaporation heat transfer showed the following results. In the case of condensation, the granulation profile became gentler, and in the case of evaporation, it became steeper compared to the droplet profile for the case of accompanying no heat transfer. The enhancement ratio of condensation and evaporation heat transfer were calculated from these droplet profile, the enhancement of condensation heat transfer on the vertical tube was gradually deteriorated, and that of the vertical falling evaporation improved further. The liquid film thickness with electrohydrodynamical granulation phenomenon flowing down adding to condensation and evaporation were calculated and the heat transfer coefficient compared with experimental data. Both enhancing ratio and characteristics of heat transfer agree well with experimental results.
- Research Organization:
- Toshiba Corp., Yokohama (JP)
- OSTI ID:
- 20030463
- Resource Relation:
- Conference: 5th ASME/JSME Thermal Engineering Joint Conference, San Diego, CA (US), 03/14/1999--03/19/1999; Other Information: 1 CD-ROM. Operating system required: Windows i386(tm), i486(tm), Pentium (R) or Pentium Pro, MS Windows 3.1, 95, or NT 3.51, 8 MB RAM, MacIntosh and Power MacIntosh with a 68020 or greater processor, System software version 7.1, 3.5 MB RAM (5 MB for PowerMac) 6 MB available hard-disk space, Unix; PBD: 1999; Related Information: In: Proceedings of the 5th ASME/JSME thermal engineering joint conference, [3600] pages.
- Country of Publication:
- United States
- Language:
- English
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