Abstract |
Combustion of any fuel requires providing oxygen (usually in the form of atmospheric air) and fuel in the proper amounts, and adequately mixed. (While combustion with pure oxygen is appropriate for some processes, the scope of this paper is for fuel and air combustion. Therefore, for simplicity, in the balance of this paper, the term "air" will be sufficient to describe the oxidizing agent in combustion.) There are several ways to bring the constituents of combustion together. One way, as in a bonfire, is simply to allow the fuel and air to find one another. (Generally, this method is not practical for an industrial process, so will not form part of the discussion in this paper.) Another way is to use a mechanical source to cause the flow of both air and of fuel (i.e. a fan or blower). A final way of combining air and fuel is to rely on natural pressure imbalances generated by temperature differences or velocity differences in order induce flows of either air or gas.; Each of these approaches has obvious advantages and obvious drawbacks. This paper focuses primarily on the relative merits of the latter two mixing strategies mentioned above. |