Swiss Roll Combustor Model

3. Findings and Discussions

Swiss roll combustor model’s success depends mainly on the stability of flame at its center and improvised flame stability limits. Flame stability at the center ensures continuous heat generation from the combustor. Flame stability limits gives an idea about how much leaner stable flame (i.e. to improve fuel efficiency) and how much richer stable flame (i.e. to get a maximum heat release) can be successfully established.

Table 1. One turn Swiss roll combustor models and their description

One turn Swiss roll combustor Model Reactants Channel

Dimension in ‘mm’ * Products Channel Dimension in ‘mm’** Combustor Cross sectional area in ‘mm2’ Depth of Combustor in ‘mm’ Tested for MLPG in ‘LPM’

D21 2 3 70 21 0.25, 0.3,

Mixture concentration marks an impression on lean limit (i.e. to ensure required fuel efficiency) and rich limit (i.e. maximum possible heat released during combustion with the compromise of fuel efficiency). Mixture of air and fuel is always compared with stoichiometric ratio (i.e. theoretically correct ratio of air and fuel which gives complete combustion) to decide lean limit and rich limit. Equivalence ratio (Phi) is the ratio of actual air-fuel ratio to the stoichiometric air-fuel ratio (i.e. ratio is calculated per mass basis to get correct results). To get a better stable flame conditions lean limit should be highest and rich limit should be lowest. Highest lean limit and lowest rich limit can be achieved by recirculation of the heat from products to reactants [3, 11]. Stable flame conditions in the combustor are improved by keeping sufficient volume to surface area ratio [7], lower thermal conducting material [8], proper balance between flame speed and mixture flow velocity (i.e. flow velocity should be less than the flame speed) [9], [10,12], providing insulation on the external surfaces of the combustor [10], by using heat recirculation from products to reactants [3 - 15] (which increases internal heat sharing between walls and