To meet the demand of turbine based combined cycle (TBCC) engine

a design concept of external parallel dual-channel variable inlet was proposed. By rotating cowls of turbine channel and ramjet channel

the inlet can regulate mass flow capture height and realize mode transition. Besides

the inlet can obtain good performance in a wide Mach range by adjusting internal contraction ratio with the Multi-linkages mechanism under the lower wall of ramjet channel. Numerical simulation method was applied to investigate the flow characteristics and the performance of the inlet. The results reveal that the variable inlet can work in a wide Mach range with good performance in the work envelope. Compared with fixed geometry inlet

the variable geometry inlet can increase total pressure recovery coefficient up to 12.5%

30.2% and 133.3% at Mach number is 2.5

3.0 and 4.0

respectively.