Cramer
Junior Member
Posts: 129 
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Post by Cramer on Dec 21, 2013 14:28:09 GMT -8
I have heard a few maximum temperatures bandied about in regards to rocket burners. I am guessing that the larger 8 inch or larger risers produce the highest temperatures but I really have seen no test results indicating what the maximum temperatures that need to be withstood in feed chamber/burn tunnel/heat riser for different sizes of rocket burners. A chart or info-graphic of tested temperatures for different sized burners burning at maximum would be a great help in material selection for different parts of the burner assembly.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Dec 21, 2013 15:29:01 GMT -8
The highest reading on my 6" batch box using my digital thermometer has been 1010°C. The reading was taken in the main riser 4" below the top of the main batch box casting. The thermometer isn't calibrated but does show 100°C when boiling water (I am approx. 50m above sea level). Video footage showing 1001°C is here. I used 1200°C insulating castable on that stove and noticed hairline cracks appearing. This might be due to heat stress, it may not. I decided to err on the side of caution so I'm using 1600°C castable refractory for my batch box stoves now. |
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Cramer
Junior Member
Posts: 129
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Post by Cramer on Dec 21, 2013 15:36:30 GMT -8
Now this is useful information! I hope others have measurements to share also. Thanks much!
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Post by peterberg on Dec 22, 2013 1:18:56 GMT -8
My highest reading has been 1173°C, taken inside the riser, about 12 cm (5") above the floor of the firebox. During every burn the flame front, being the hottest, is elevated inside the riser and come down again when it's past the hottest minutes. Highest reading at the end of the riser during full burn has been 910°C. Both readings are exeptions, but these do illustrate the levels that can be achieved.
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Cramer
Junior Member
Posts: 129
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Post by Cramer on Dec 22, 2013 6:29:40 GMT -8
That is exactly the kind of information I was seeking! Once again Peter, my thanks to you sir! You have been playing with fire for a long time so I think I can "take that figure to the bank!" (I am rife with colloquialisms  ). |
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Dec 22, 2013 15:22:05 GMT -8
I was demonstrating the stove to some friends who came round to lunch today. After two full loads of wood, the temperature inside the batch box itself was 660°C. This reading was taken 4" from the door at the ember stage. I only have a 6" probe and it was too hot to take a reading in the riser.
I also took a reading of the temperature of bricks on the second course down on the bell at the same time - this was 170°C. Halfway down the bell was 130°C.
Over the holidays I need to do some proper recordings. Will post as and when I have them.
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