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 September 1, 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 September 1, 2014).

Share This




More Matter & Energy News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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