Numerical Investigation of a VTOL Power Unit Based on Gas-Driven Fan

A concept of VTOL power unit which based on gas-driven fan was presented in this paper. And its aerodynamic characteristics of designed point were numerically investigated. The results shown that it has a relatively good thrust and lift characteristics and can be used as a power device for VTOL aircraft. The 2D flow characteristics indicated that the intake has a greater influence on the thrust of the power unit, and the main influencing factors are the rounding radius of the intake and the intake height. The 3D numerical simulation further demonstrated the effect of the intake height. In this paper, δ is equal to 0.568 when H is equal to 0. 382D, and even under the condition that H=0.25D, the flow is substantially smooth, δ is only equal to 0.728. However, the total pressure recovery of the intake under these conditions is at a relatively high level due to a large rounding radius at the front of the intake.