考虑进气道反压不起动的冲压级数学建模及再起动路径研究

At present，the research on unstart characteristic modeling and restart methods of ramjet engines which used in combined cycle is insufficient. Firstly，according to the matching relationship of ramjet flow rate，a set of ramjet stage full-condition model that can qualitatively reflect the unstart oscillation process is established. Secondly，the monitoring algorithm is used to monitor the unstart state of the model，and the unstart boundary of the ramjet stage under different Mach numbers is obtained. Thirdly，a fast restart path based on geometric relationship and an equal-thrust restart path based on performance parameters are proposed. Finally，the pullback performance of the two restart paths and the existing univariate restart path is compared. The simulation results show that the restarting effect of the two restarting paths is consistent with the expected effect of the path design，and the restarting pullback can be guaranteed under each unstart condition，and it has significant advantages compared with the single-variable path. From the perspective of restart duration，the average pullback speed of the fast restart path is the fastest，and the average pullback time is 1.275s. From the perspective of restart thrust loss，the equal-thrust restart path can ensure the minimum restart thrust loss while pulling back faster，with an average of no more than 0.43%，and which has better restarting performance.