Exploring mode transition with air mass flow smoothing of small turbine/ramjet engine (TRE)

In our opinion, when we use TRE for long-distance and hypersonic flight, the effect of closing off the turbojet engine for protecting it from the high Mach airflow and the matching of the performance of a turbojet engine with that of a ramjet engine around the mode transition range are important areas of interest that need to be but have not yet been evaluated. Section 1 of the full paper explains our method of evaluation. The core of subsection 1.1 is that it presents the flow chart for computing the performance parameters and thermodynamic parameters of a certain type of small TRE and gives the criteria of determining the design parameters of the TRE. The core of subsection 1.2 is that it optimizes the reasonable mode transition range according to the computed performance parameters and thermodynamic parameters along the flight trajectory and design limits such as the Mach number at the entrance of a ramjet burner which should be less than 0.3. The core of subsection 1.3 is that it analyzes the effect of the opening area of a mode transition valve on the thermodynamic parameters, especially the relationship between the total pressure of the mixer inlet of TRE and its static pressure. Section 2 presents the calculation results, given in Figs. 3 through 6 and 8 through 12, and their analysis for a certain type of small TRE; in particular, the analysis determines the optimal mode transition range of this type of small TRE.