Affiliation:
1. Nanjing University of Aeronautics and Astronautics, 210016 Nanjing, People’s Republic of China
Abstract
Boundary layer combustion is an approach to the reduction of skin friction in hypersonic propulsion systems based on reducing the Reynolds shear stress in the turbulent boundary layer by combustion heat release. In this study, the Reynolds-averaged Navier–Stokes methodology is adopted to study the drag reduction characteristics of boundary layer combustion in high enthalpy flow. Two novel explanations of the local increase in skin friction caused by ignition delay are given in terms of flow structure and the Kármán momentum integral equation, respectively. In addition, it is found that the inhibitory effect of combustion heat release on Reynolds shear stress is gradually weakened with increasing total enthalpy, which is detrimental to drag reduction. Finally, a combination of radical farming and boundary layer combustion is proposed to improve the drag reduction effect. This approach is verified by using a two-dimensional simplified M12-02 scramjet model, with the results indicating that radical farming can considerably suppress ignition delay and thereby further benefit drag reduction and combustion.
Funder
National Science and Technology Major Project
Science Center for Gas Turbine Project
National Natural Science Foundation of China
Publisher
American Institute of Aeronautics and Astronautics (AIAA)