(6ev) Research on the Vertical Falling Film Behavior in the Scrubbing-Cooling Tube

Research Interests: Chemical Engineering, Gasification,
Fluid flow, Heat and mass transfer

Teaching Interests: Principle of transport process

Research on the vertical falling film behavior in the
scrubbing-cooling tube

Yifei Wang*, Xin Peng, Liucheng Yan , Guangsuo
Yu, Fuchen Wang

Key Laboratory of Coal Gasification and Energy Chemical Engineering
of the Ministry of Education, East China University of Science and Technology,
Shanghai 200237, PR China

Being
a part of the opposed muti-burner (OMB) gasifier, the
scrubbing-cooling chamber is used to cool, humidify and scrub the high
temperature raw syngas. The chamber mainly consists of a scrubbing-cooling
ring, a scrubbing-cooling tube, a liquid pool and a bubble bed. The cooling
water flows through the ring and forms vertical liquid film inside the tube.
The liquid film protects the wall of the tube from the high temperature syngas
and slag. Most of the falling film studies are carried out in micro-scale tube with
small liquid Reynolds number. The research here focuses on the study of both of
the velocity and thickness distribution of falling liquid
film under relatively large Reynolds number which is closed to actual industrial
condition.

An
Ultrasound Doppler Velocimetry was employed to measure the velocity and
thickness distribution of falling liquid film and the liquid Reynolds number
ranged from 1.0¡Á10⁴ to 3.1¡Á10⁴. A 3D numerical model of
the scrubbing-cooling tube was established and the simulation results were in
good agreement with the experimental data as shown in Fig. 1. The average
liquid film thickness became largest at the 0 circumferential position while a
part of the liquid was separated from the local liquid film and dripped in the
gas core when Reynolds number was larger than 1.5¡Á10⁴ as shown in
Fig. 2-3. In the lower section of the tube, the circumferential liquid film thickness
distributed more evenly. With the increase of Reynolds number, both of the
thickness and velocity of global liquid film increased and the thickness
distribution became unevener. Under the effect of
gravity, the liquid film velocity increased with the increasing flow distance
at small Reynolds numbers while decreasing at large Reynolds numbers due to the
resistance.

Keywords: falling film, film velocity and thickness, numerical
simulation, large Reynolds numbers, Ultrasound Doppler Velocimetry

Fig. 1 Comparison of
liquid film velocity distribution between simulated and experimental data

Fig. 2 Liquid film thickness distribution at different
Reynolds numbers

Fig. 3 Phase contour graph of the outlet of the tube

1. Name of poster
session you would like to submit to: Fluid Mechanics

2. Abstract Title:
Research of the
vertical falling film behavior in the scrubbing-cooling tube

2. Presenting
author and all co-authors, with affiliations and emails for each:

Yifei Wang, East China University
of Science and Technology, wangyf@ecust.edu.cn

Xin Peng, East China University of Science and
Technology, Y10150127@mail.ecust.edu.cn

Liucheng
Yan, East China University of Science and Technology, 413733589@qq.com

Guangsuo
Yu, East China University of Science and Technology, gsyu@ecust.edu.cn

Fuchen
Wang, East China University of Science and Technology, wfch@ecust.edu.cn

3. Abstract: As seen in Page 1 and 2.

4. Keywords: falling film, film velocity and thickness,
numerical simulation, large Reynolds numbers, Ultrasound Doppler Velocimetry