Numerical investigations on a comparison between counterflow and coflow double-channel micro combustors for micro-thermophotovoltaic system

A high and uniform wall temperature on micro combustors is desirable for Micro TPV system application. In this work, extensive numerical investigations of H-2/air premixed combustion in the coflow and counterflow double-channel micro combustors are conducted under various H-2 mass flow rates, H-2/air equivalence ratios and solid materials. Moreover, in order to characterize the uniformity of wall temperature, a nonuniformity coefficient R-T,R-w is introduced. Results show that the mean outer wall temperature of the coflow double-channel micro combustor is slightly higher than that of the counterflow double-channel micro combustor and the outer wall temperature nonuniformity of the counterflow double-channel micro combustor is greatly lower than that of the coflow double-channel micro combustor, meaning that the counterflow double-channel micro combustor has better thermal performance than the coflow double-channel micro combustor. More importantly, some critical values about the H-2 mass flow rate, H-2/air equivalence ratio and solid material are determined for keeping the better thermal performance of the counterflow double-channel micro combustor. This design offers us another way for assembling the single-channel micro combustor into the double-channel micro combustor. (C) 2017 Elsevier Ltd. All rights reserved.