Burner quarl

A refractory quarl is usually an integral part of forced-draft burners. Suitable design of burner and quarl can determine the flame characteristics. Long, short, pencil or even flat flames are possible. 

In most practical systems, e.g., combustors or furnaces, the combustion process is much more comphcated because of two important factors. First, to a large extent the fuel and oxidant are mixed within the quarl of a burner or within the combustion chamber itself. The mechanism of the reactant mixing therefore plays an important role. Second, the flow aerodynamics are complicated by the flow recirculation and turbulence and frequently cannot be represented by simplifled models. 

They found fhat the same swirl generator can provide different velocity patterns as the relative furnace size dj/ di, is changed. At the same time, the size and the shape of the internal or central recirculation zone (CRZ) is primarily dependent on furnace diameter and not vane swirler diameter. Cristea [15,16] in 1984 and 1987, respectively, introduced, relative to a complete system swirler-quarl-furnace, a new modified swirl number in which the characteristic length is the exit diameter of the burner quad. 

The analysis of flow pattern models occurring inside the radial distribution of the velocity vector components and the pressure at swirl generator exit are nonuniform the same burner equipped with an annular vane swirl generator in the same furnace can produce different velocity vector components, when the quarl geometry is changed (dQ/di, = 2-3.5) the shape and size of CRZ are primarily a function of quarl geometry and not of vane swirler diameter. 

As mentioned by Spalding [19], the strict requirements of similarity theory are so numerous that exact scaling of any practical combustion system is impossible because the requirement for one dimensionless group to maintain constant is often incompatible with the another criteria requirements. Two elements must be considered simultaneously when scaling a combustion system (i.e., burners and its quarl) and the furnace forming the so-called complete burning system. Thus a complete combustion should be scaled in accordance with the following main criteria ... 

The reaction takes place within sight of both the product and the furnace refractories, both of which absorb some reaction heat (unlike a burner tile of quarl)... 

A technology often used delays the burning so that most of it occurs out in the furnace rather than inside the burner tile (or quarl), then it is possible to inspirate inert furnace gases into the combustion air and/or fuel being supplied to the combustion reaction. 

Quarl Block. A refractory shape forming the whole, or a segment, of a gas- or oil-fired burner, particularly in a boiler furnace or glass-tank furnace. 

Quarl Throat An opening in the wall of a boiler furnace, into which a burner is set Quarry. (1) An open-cast working of rock. 

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