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Post by fiedia on Mar 21, 2023 0:24:03 GMT -8
I read that one should keep a minimum 30 cm (12”) distance between bell ceiling and heat riser top. On my 200mm (8”) batch, I need to reduce that distance to 11cm (4.5”). Logically it should work as the CSA ratio cylinder above HR/ HR area = 2.2.
At what distance of the HR do you put your bell ceiling? Any experiment playing with this parameter? |
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Post by peterberg on Mar 21, 2023 2:25:47 GMT -8
I read that one should keep a minimum 30 cm (12”) distance between bell ceiling and heat riser top. On my 200mm (8”) batch, I need to reduce that distance to 11cm (4.5”). Logically it should work as the CSA ratio cylinder above HR/ HR area = 2.2. At what distance of the HR do you put your bell ceiling? Any experiment playing with this parameter? In order to keep instructions simple: the top gap the same as the system size, that prevents friction where gas velocity is highest. In your specific case: I would choose for a riser that's lower than the 10 times base number. Down to 8 times there's very little difference, above 10 times there's nothing to gain. To be honest, I never took the trouble to find out the smallest top gap that the thing would still work. That 30 cm is twice the system size for a 150 mm heater by the way. |
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Post by fiedia on Mar 21, 2023 11:23:34 GMT -8
Thank you for your answer Peterberg.
My heat riser height is presently 8.4 times the base number. I can gain 7cm (3") which will make the gap almost as big as the system size (18cm vs 20cm). It is worth trying that way.
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yan23
New Member
Posts: 2
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Post by yan23 on Apr 6, 2023 13:12:03 GMT -8
If I may just jump in on this one ? Do you think there may be a benefit from having a dome shaped top to the bell or something similar to guide the gas ? Just curious more than anything. Also is there a minimum recommended height for the top of the barrel in a standard RMH in terms of system diameter ?
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