In the last few years gas combustion technology has undergone important innovations especially in residential heating appliances. In particular, requirements on low emissions together with load modulation has led to the use of premixed combustion technologies besides traditional diffusive flames. Constant demand for smaller overall dimensions and cost optimization has led to design combustion chambers with higher combustion intensity and this has led to premixed surface burners, then to radiant burners, and then to metallic mat burners in particular. With the metallic mat combustion flame front stabilizes above a metallic mat and at specific power loads is located inside. It differs from porous matrix combustion where combustion takes place inside a solid. If the initial calculations show that the convection heat exchange is not enough to establish the designed combustion intensity, the use of radiant burners becomes decisive. The radiative contribution of the mat is naturally predominant in the power range when flame develops within the mat itself. Apart from the radiative contribution, the metallic mat has others functions: it increases the operating margin with regards to flame lift-off and flashback that can happen with the variation in excess air and gas type like the light-back limit gas (as defined in EN676). Metallic mat combustion is widely used in residential heating (at least in Europe) especially in those applica-tions where condensation is sought. It is also used in process applications like bread ovens, paint ovens and where a radiant load is required. In the following, metallic mat combustion technology will be described with special reference to metallic mat production technology and material selection. Next, testing for such technology and especially combustion testing will be presented. At the end some design issues regarding combustion chamber coupled with this tech-nology will be given.

Metallic mat gas combustion

ZAMBON, ANDREA
2010

Abstract

In the last few years gas combustion technology has undergone important innovations especially in residential heating appliances. In particular, requirements on low emissions together with load modulation has led to the use of premixed combustion technologies besides traditional diffusive flames. Constant demand for smaller overall dimensions and cost optimization has led to design combustion chambers with higher combustion intensity and this has led to premixed surface burners, then to radiant burners, and then to metallic mat burners in particular. With the metallic mat combustion flame front stabilizes above a metallic mat and at specific power loads is located inside. It differs from porous matrix combustion where combustion takes place inside a solid. If the initial calculations show that the convection heat exchange is not enough to establish the designed combustion intensity, the use of radiant burners becomes decisive. The radiative contribution of the mat is naturally predominant in the power range when flame develops within the mat itself. Apart from the radiative contribution, the metallic mat has others functions: it increases the operating margin with regards to flame lift-off and flashback that can happen with the variation in excess air and gas type like the light-back limit gas (as defined in EN676). Metallic mat combustion is widely used in residential heating (at least in Europe) especially in those applica-tions where condensation is sought. It is also used in process applications like bread ovens, paint ovens and where a radiant load is required. In the following, metallic mat combustion technology will be described with special reference to metallic mat production technology and material selection. Next, testing for such technology and especially combustion testing will be presented. At the end some design issues regarding combustion chamber coupled with this tech-nology will be given.
2010
Industrial combustion testing
9781420085280
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2422220
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