Study on Flow and Heat Transfer Characteristics in Lamilloy Structure with Different Configurations of Internal Minichannels

This paper proposes a novel lamilloy cooling structure equipped with internal minichannels used in a combustor flame cylinder. The overall flow and heat transfer characteristics of three different internal minichannel configurations (parallel-flow, counter-flow, and staggered arrangements. PF, CF, and SF for short) are analyzed and compared. From the analysis of the heat transfer characteristic, it is found that the CF structure possesses the best cooling effect and temperature uniformity. The average cooling effectiveness (eta ave) of the CF structure increased by 20.6% and 20.4%, and the average temperature gradient ((dT/dX)ave) decreased by 76.9% and 32.8%, compared with the SF structure and PF structure, respectively. From the analysis of flow characteristics, the coolant ejected from the minichannel one region of the SF structure completely blocks the direct contact between the mainstream and the lamilloy, while transferring more from the mainstream to the minichannel two region. Different from the SF structure, film cooling at the two outlet of the CF structure transfers most of the mainstream to the lower position, which further improves the cooling effect of the two internal minichannels.