An SSM Jet-Flame Optimized “Open Fire”

Last week we wrote about using the LEMS to tune up a stove, so it makes sense to share the actual results of a recent test series with you this week.

When ARC makes an Open Fire, we often use three bricks on end to hold up the pot. The bricks are 16cm high. It has been fascinating to experiment with the SSM Jet-Flame in the open fire to try and determine how fuel-efficient and clean burning the combination can be. Last month, we spent a couple of weeks changing one thing at a time and then completed nine 30-minute ISO high power tests on the close-to-optimized design.

Here are the test results:

Description of the changes

• We kept the pot height at 16cm above the top of the Jet-Flame.
• Three rebar supports held up the pot replacing the heavier and bulkier bricks.
• A short 6cm high by 18cm long FeCrAl fence kept the sticks on top of the combustion zone in the Jet-Flame.
• A lightweight Winiarski 304 stainless steel “0.7 constant cross sectional area” stovetop increased the heat transfer efficiency from the hot flue gases into the pot.
• Thermal efficiency was also improved with an 11cm high pot skirt creating a 6mm channel gap on the sides of the 26cm in diameter pot.
• We learned that the sides of the open fire should be partially enclosed for best performance. A 5cm high opening at the lower portion of the sides of the open fire allowed fresh air to enter the combustion zone. 11cm of the upper portion of the sides of the Open Fire were enclosed with aluminum foil.
• To make sure that there was no backdraft, a 7cm tall, 14cm wide and 7cm deep metal fuel tunnel was added on the outside of the sides of the partially enclosed Open Fire.

Photo of the experiment

Conclusion

It looks like a Rocket combustion chamber may not be needed to achieve Tier 4/5 results from an “Open Fire” when tested in a lab. A short fence that holds a single layer of sticks on top of the primary air jets seems to be as good.