| OCR Text |
Show specific firing conditions, and particularly of stoichiometry, provided that the firing parameters (other than firing rate) are held constant in a set sequence of experiments. Change in firing parameters from one experimental sequence to another is then identified by change in the Firing Constants: Ht, Ham, and 0.0; which can be formulated as functions of equivalence ratio, as partly shown in this paper. The dependence of the Firing Constants on the equivalence ratio IS of particular importance in determining the thermal performance characteristics of a furnace or engine, which is reason for the emphasis in this paper. However, this dependence is only broadly known at this time, and eperimental verification of the dependencies is still very limited. There are three related problems here, with two addressed in this paper. The first is the development of more complete expressions for the dependence of the Firing Constants on stoichiometry, and these are now given in a recent paper [5]. The second is reformulation of the Firing Equation to include the effect of stoichiometry by re-writing the thermal input term, He, in a form that includes the firing rate at stoichiometric or at some other reference equivalence ratio; this development is given here. The third, also given here, is experimental evaluation of the expression developed. For that evaluation, experimental data obtained earlier (1966) from a small laboratory furnace is used [8]. The result provides a base for a further generalization of the results which is needed for future application to a wider range of devices. 3. Theory. Derivation of the Firing Equation CEq. 1) is based, as already noted, on application of the integral energy equation to a closed control volume. At steady state, this yields [3-5] the overall balance between input (Hr), and the sum of-the output (H,) and losses in the exhaust (Hs) and through the walls (Hw), thus: He = Hw+Hs+ H, [3] The exhaust loss, Hg, is redefined in terms of the thermal input, Hr, using the product of the firing rate, F, and a specific exhaust enthalpy, hg, defined per unit nlass of fuel, thus: 4 |
