Regarding the opening and fuel/air mixture, the ideal would be a much smaller air intake or oven mouth. Kilns have a way smaller air intake to achieve the ideal air/fuel mixture, but are fired with a much more controlled and gentle firing schedule than oven operators use. Unfortunately, having an ideal air intake for an oven would result in an oven mouth so small that working the oven during cooking would be almost impossible because of poor access. Some folk have found that they can decrease the air intake with their oven door placed partially closed to reduce the air intake to achieve the ideal air/fuel mixture and some going as far as creating a special door with a small air intake at the base (see blast doors). Personally I would caution against this because although the temperature will rise very rapidly under these conditions it is far too rapid a rise for the refractory material to cope with as sudden temperature rise also means uneven thermal expansion. Far better to give the structure time to expand evenly. A general rule for potters firing their kilns without damaging their wares from thermal shock is 100C/hr rise, yet we fire our ovens at more like 300C/hr. Granted potters wares are more delicate than brick or refractory, but the same principle applies. Taking it slow with the oven mouth fully open is far safer and produces greater longevity for your oven.
Further consideration should be given to the rate of heat travel through brick or refractory. As they are not particularly conductive, as a general rule heat will take “around an hour to travel an inch”. This is actually quite useful as it also works the other way around when cooling. This means the material will store the heat releasing it relatively slowly, far more suitable than a more conductive material like steel.
The drawings explain all of this.
Taking a brief look at your drawings shows a flue with a horizontal section. This tends to reduce flow, particularly at start up which could result in smoking out your restaurant. Generally nothing flatter than 45 degrees is preferred.
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