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ID# 20118, DISTRIBUTION A. Approved for public release: distribution unlimited.
Advancing the Propane Fast Cookoff Burner and Testing
Ephraim Washburn, Ross Falen, and Jeffrey Prevost
Naval Air Warfare Center Weapons Division, China Lake, California
David Hubble and Jon Yagla
Naval Surface Warfare Center Dahlgren Division, Dahlgren, Virginia
Abstract
Propane burners have already been shown to produce the temperature and heat flux
requirements to replicate the thermal environment of a liquid-pool-fire fast cookoff test.
Ordnance items tested for fast cookoff in both propane burners and liquid pool fires have shown
to have comparable reactions in the test. Further design work was done on the propane burner
to allow it to be used to test larger ordnance items. The fuel delivery system to the larger burner
was optimized and calibration showed that it produced a uniform flame that met the thermal
requirements. It was then used to test a 500 lb bomb which was also tested in a liquid pool fire.
The results of the testing are compared and demonstrate the ability to test large ordnance items
in the propane burners. Additional testing was performed on an ammunition can containing a
large number of energetic items. This test demonstrated that the multiple reactions that occur in
such a test do not damage the burner or cause the test to change. Within the variation expected
from fast cookoff testing the results from this test were very similar to the results from an
identical test that was performed in a liquid pool fire. These test results continue to show that
propane burners are safer, less expensive, and more environmentally friendly compared to the
liquid pool fire for conducting fast cookoff tests.
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Expansion of Large Burner
The propane burner located at China Lake, CA was increased from 3.1 m by 6.1 m (10 ft
by 20 ft) to 4.6 m by 6.1 m (15 ft by 20ft). The smaller burner had met the temperature and heat
flux requirements for a 4.3 m by 1.2 m by 1.8 m (14 ft by 4 ft by 6 ft) volume in the flame hearth
[1]. However, the burner was increased in size to have greater flame coverage and the burner
design was changed to have evenly spaced burner pipes throughout the entire length of the
burner. The burner was then calibrated using a thermocouple grid and heat flux gauges. The
burner with the thermocouple grid is shown in Figure 1.
Figure 1. 4.6 m by 6.1 m Propane Burner Built at China Lake
During the testing with the thermocouple grid, there was higher than desired wind and no
consistent temperature volume was measured. Also, in operation, the burner did not
qualitatively produce as high a flame as the 3.1 m by 6.1 m burner. The surface area of the
