Pyrolysis coking performance of supercritical n-decane in additively manufacturing channel

Surface roughness has a significant impact on the heat transfer and coking performance of supercritical hydrocarbon fuel. In this study, experiments are conducted to investigate the heat transfer and pyrolysis coking performance of supercritical n-decane in conventionally mechanical manufactured (CM) channel and additively manufacturing (AM) channel. Under the wall heat flux of 1.4 kW, the total coking amount in the AM channel is evenly 36.22 % less than CM channel, the corresponding average wall temperature is 35 degrees C lower than CM channel. The heat transfer in the AM channel is enhanced, resulting in less coking amount. In addition, the coke characteristics of different coking time in CM channel and AM channel has been characterized by scanning electron microscopy (SEM), Raman spectroscopy and temperature programmed oxidation (TPO). According to be observed by SEM for the CM channel, filamentous carbon generates firstly, and then covered with amorphous carbon as increasing coking time. While in AM channel, the growth of coke is mainly amorphous carbon. Moreover, it is revealed by Raman data that coke has a lower degree of graphitization in AM channel than that in CM channel. Furthermore, coke in AM channel has a lower oxidation temperature than that in CM channel from TPO results.