Numerical identifications of T-shaped rod effect on thermal performance and exergy efficiency in methane/air combustion

Abstract

To maximize the power output of micro-thermophotovoltaic systems, achieving a high and uniform wall temperature is desirable. Towards this goal, this work proposes a novel combustor with inserting a T-shaped rod and assesses the effectiveness of such a strategy in determining the thermal and exergy performances with a validated computational model. Results indicate that introducing such strategy results in a 50.4 K wall temperature elevation and a 30.5 % decrease in the temperature standard deviation at the inlet velocity of 0.6 m/s. The effectiveness of applying a T-shaped rod on wall temperature is also found to be dependent on the inlet velocity. In addition, the optimal equivalence ratio associated with the highest wall temperature is shown to be stoichiometric caused by the relatively larger volumetric thermal power density. Further analysis of the pressure loss and exergy energy is performed. While the presence of a T-shaped rod can lead to an increase in the pressure loss, these are negligible relative to the ambient pressure. Furthermore, in addition to the temperature enhancement, the T-shaped rod combustor is associated with a higher exergy and exergy efficiency, which is beneficial to improving the energy efficiency of combustion devices. This work provides valuable insight into enhancing the wall temperature and energy conversion efficiency for micro-power systems.