Featured Research

from universities, journals, and other organizations

Liquid Film-Thickness Measurement Technique Is Fast And Inexpensive

Date:
June 6, 2000
Source:
University Of Illinois At Urbana-Champaign
Summary:
Precise measurements of film thickness at liquid-vapor interfaces are important in commercial applications such as power plants, oil refineries and refrigeration systems, but are often expensive and difficult to make. Now researchers at the University of Illinois have developed an automated optical film-thickness measurement technique that is both inexpensive and nonintrusive.

CHAMPAIGN, Ill. -- Precise measurements of film thickness at liquid-vapor interfaces are important in commercial applications such as power plants, oil refineries and refrigeration systems, but are often expensive and difficult to make. Now researchers at the University of Illinois have developed an automated optical film-thickness measurement technique that is both inexpensive and nonintrusive.

Related Articles


The technique works by shining light from a light-emitting diode on the outside of a transparent tubular test section. Some of the light is reflected by total internal reflection at the liquid-vapor interface and forms a sharp ring on the outside of the tube. By measuring the diameter of the ring, the researchers can determine the film's thickness to an accuracy of one-hundredth of a millimeter.

The noninvasive technology is based on a measurement technique patented in 1997 by UI mechanical engineering professor Ty Newell and graduate student Evan Hurlburt (now a postdoctoral research associate in the UI department of chemical engineering). Recent improvements by graduate student Tim Shedd have turned the technique into a sophisticated film-thickness measurement system that also provides a unique research capability.

"In this application, light is reflected from the surface of a liquid film flowing over a transparent wall," Shedd said. "The reflected light generates an image on the outside of the wall which is captured by a CCD [charge-coupled device] camera and digitized in a computer. The resulting image is processed using custom software to produce an accurate film-thickness measurement."

Unlike other measurement methods that are based on electrical conductivity, dye injection or light absorption, the new technique does not disturb the flow itself, Shedd said. "So you can insert it nearly anywhere in a system and obtain reliable results. And because the technique is automated, several hundred film thickness readings can be taken in just a few minutes."

In addition to many commercial applications -- such as monitoring quality control in chemical-processing plants or sensing potential cooling failures in nuclear power plants -- the measurement technique can serve as a powerful, analytic research tool. In one project, for example, Shedd is exploring how effectively liquid refrigerants "wet" the walls in various square- and triangular-shaped tubes for potential use in highly efficient heat exchangers.

"We need to understand how the fluid is spread around the inside of the tube and measure its thickness profile in order to understand the effective heat transfer," he said. "Knowing the distribution of the liquid film is also very important in determining how much energy must be expended in pushing the refrigerant through the pipe."

Shedd's work was supported by the UI Air Conditioning and Refrigeration Center, a National Science Foundation industry/university cooperative research center.


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Liquid Film-Thickness Measurement Technique Is Fast And Inexpensive." ScienceDaily. ScienceDaily, 6 June 2000. <www.sciencedaily.com/releases/2000/06/000602074023.htm>.
University Of Illinois At Urbana-Champaign. (2000, June 6). Liquid Film-Thickness Measurement Technique Is Fast And Inexpensive. ScienceDaily. Retrieved March 5, 2015 from www.sciencedaily.com/releases/2000/06/000602074023.htm
University Of Illinois At Urbana-Champaign. "Liquid Film-Thickness Measurement Technique Is Fast And Inexpensive." ScienceDaily. www.sciencedaily.com/releases/2000/06/000602074023.htm (accessed March 5, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, March 5, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did the Simpsons Figure out the Higgs Boson Particle Years Before Scientists

Did the Simpsons Figure out the Higgs Boson Particle Years Before Scientists

Buzz60 (Mar. 4, 2015) During a 1998 Simpsons episode, Homer Simpson scribbled a seemingly gibberish equation on a chalkboard. Turns out that equation is a shake off from predicting the actual nano mass of the God Particle. Patrick Jones (@Patrick_E_Jones) explains. Video provided by Buzz60
Powered by NewsLook.com
Wearables Now the Must-Haveables

Wearables Now the Must-Haveables

Reuters - Business Video Online (Mar. 3, 2015) Telecom company executives are meeting in Barcelona for the Mobile World Congress, the largest annual trade show for the wireless industry. As Ivor Bennett reports from the show wearable technology is one of the big themes. Video provided by Reuters
Powered by NewsLook.com
Forensic Holodeck Creates 3D Crime Scenes

Forensic Holodeck Creates 3D Crime Scenes

Reuters - Innovations Video Online (Mar. 3, 2015) A holodeck is no longer the preserve of TV sci-fi classic Star Trek, thanks to researchers from the Institute of Forensic Medicine Zurich, who have created what they say is the first system in the world to visualise the 3D data of forensic scans. Jim Drury saw it in operation. Video provided by Reuters
Powered by NewsLook.com
Solar Plane Passes New Test Ahead of World Tour

Solar Plane Passes New Test Ahead of World Tour

AFP (Mar. 2, 2015) A solar-powered plane made a third successful test flight in the United Arab Emirates on Monday ahead of a planned round-the-world tour to promote alternative energy. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins