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Post by frankdaly on Dec 17, 2015 8:06:34 GMT -8
OK, well I'm just casting a firebox for a 6" (150mm) system. The firebox is 9"x13"x17". The port is 9 1/2"x2"x2". If I were to implement the "chet" into this port at 12.5% CSA of the riser at the top third of the port it would need to be approx. 11mm wide. does that sound correct to you guys and does it sound feasible? And I should mention that I'm trying to use just an 18" riser.
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Post by shilo on Dec 17, 2015 9:58:23 GMT -8
at first, we all thought that the secondary air bring o2 and the goal is to do more and more secondary and less and less primary and the total will be less then 25%. instead of 20+5 we want it to be 10+10 for example. the next level of understanding was that there is enough o2 and the secondary air is for directing and mixing the flame pass so we don't need large amount of air, we need a well locating air. now adiel say and I start to agree, that the reel point is the velocity. the added gas increase the velocity at the port and the velocity do the mixing. so we need to think about the direction and about the speed.
if to say numbers, it can be 1-4% of the csa but it bring air under big pressure differences so probably it give a lot of air.
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Post by shilo on Dec 17, 2015 10:01:12 GMT -8
we used 3.5mm slits. more research is needed to say if that the optimum or not.
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Post by frankdaly on Dec 17, 2015 12:44:18 GMT -8
OK thanks Shilo, I've cast it at 3.5mm wide by 200mm long up both sides of the top third and across the top of the port about 7 or 8 mm from the riser. this makes it 4% of riser csa. I'll make the primary air port 20% csa but adjustable. Thanks for the help.
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Post by patamos on Dec 19, 2015 9:13:03 GMT -8
Frank, i am pretty sure the chet portal is best located horizontally on the sides and back walls of the heat riser just above where it meets the batch box. But maybe i have missed some of the news from experiments...
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kpl
New Member
Posts: 47
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Post by kpl on Jan 4, 2016 5:12:19 GMT -8
Can that EGR be sucked from below the batch box? That way, one could build a simple batch box with exhaust to chimney above the batch box (So it's always warm enough not to stall) but EGR sucking would cause enough gas movement below, to heat up the mass, located there. I'm a bit afraid to make the chimney exit down there, as the only chimney I can use would be about 2 meters of tin tube.
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