Comment on 'Mechanics of Combustion Mode Transition in a Direct-Connect Ramjet-Scramjet Experiment'

摘要

IN A recent study. Matthew L. Fotia conducted an analysis about the mechanics of combustion mode transition. We appreciate his efforts in trying to shed light on the understanding of discontinuous variation in pressure during the mode transition. Three sets of nonallowable flow configurations in the isolator are identified, and the author claimed that one of them was associated with negative entropy generation based on the second law of thermodynamics analysis of the isolator impulse theory of Heiser and Pratt. This is a critical conclusion for the scramjet research, which theoretically demonstrates possible performance mutations during the flight. However, we find that the formula derivation and the physical model used to describe the isolator core flow are not absolutely correct.