Featured Research

from universities, journals, and other organizations

Combustion Of Composite Propellants Studied At Microscopic Level

Date:
December 3, 1999
Source:
University Of Illinois At Urbana-Champaign
Summary:
Researchers at the University of Illinois are investigating the microscopic combustion behavior of composite propellants, an important step in improving the performance and reliability of solid-fueled launch vehicles and high-speed interceptors.

CHAMPAIGN, Ill. - Researchers at the University of Illinois are investigating the microscopic combustion behavior of composite propellants, an important step in improving the performance and reliability of solid-fueled launch vehicles and high-speed interceptors.

The workhorse of solid rocket motors, composite propellants consist of a heterogeneous mixture of fuel and oxidizer - generally with the oxidizer as a crystalline material surrounded by a fuel-polymer matrix. A common example is ammonium perchlorate and hydroxyl-terminated polybutadiene binder.

"Ammonium perchlorate has been used in solid propellants for decades, and hydroxyl-terminated polybutadiene binder has been phased into production in the last decade, but fundamental questions remain about their combustion behavior," said Quinn Brewster, a professor of mechanical engineering at the U. of I. "Our work investigates the microscopic behavior of the propellant in a simplified geometry that allows easier measurement and comparison with theory."

To study combustion chemistry at the microscopic level, Brewster and his students first form a small propellant sandwich consisting of a layer of fuel between layers of oxidizer. The sandwich is then ignited in a laser-augmented, high-pressure combustion chamber, and the resulting reaction recorded with an intensified CCD (charge-coupled device) camera.

"An optical chopper permits the sequential acquisition of two nearly simultaneous images - one of the flame emission alone, the other with the sample backlit with an ultraviolet source," Brewster said. "A narrowband filter rejects most of the light except that given off by excited hydroxyl molecules."

By studying the CCD images, the researchers were able to examine how the combustion behavior of propellant sandwiches varied with pressure and oxidizer width. "We found that the burning rate increased and the flame enlarged at high pressures," Brewster said. "Increased pressure and wider oxidizer layers also tended to cause the flame to split."

Through parallel computational simulation studies, the researchers further explored the flame structure and energy-transfer characteristics of the combustion reaction. "We used a two-reaction model where the oxidizer is allowed first to react and form an intermediate species which then combines with the fuel in the second reaction," Brewster said. "This double-reaction sequence provides a simple approximation of the complex flames seen in our laboratory experiments."

The simulation shows an initial flame and two leading-edge flames forming over the oxidizer portion of the propellant. "The initial flame splits due to the influence of these two edge flames, which are anchored close to the surface," said Brewster, who presented his team's findings at the Joint Army, Navy, NASA, Air Force (JANNAF) meeting in Cocoa Beach, Fla., on Oct. 22. "The edge flames provide additional heat which raises the reaction rate of the initial flame."


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. "Combustion Of Composite Propellants Studied At Microscopic Level." ScienceDaily. ScienceDaily, 3 December 1999. <www.sciencedaily.com/releases/1999/12/991203081644.htm>.
University Of Illinois At Urbana-Champaign. (1999, December 3). Combustion Of Composite Propellants Studied At Microscopic Level. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/1999/12/991203081644.htm
University Of Illinois At Urbana-Champaign. "Combustion Of Composite Propellants Studied At Microscopic Level." ScienceDaily. www.sciencedaily.com/releases/1999/12/991203081644.htm (accessed July 31, 2014).

Share This




More Matter & Energy News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
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:
from the past week

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