Method of Characteristics Design of High-Temperature Wind Tunnel Nozzles with Vibrational Relaxation

摘要

A nozzle design method using the rotational method of characteristics and incorporating results from supporting RANS simulations was developed for high-temperature nozzle design problems. The project is motivated by the development of a new high-temperature hypersonic wind tunnel at the University of Maryland. We extend the classic method of characteristics (MoC) approach summarized by Sivells Sivells (J. Spacecraft & Rockets, 7:1292-1299, 1970)1 to vibrational nonequilibrium flows. Data from the supporting RANS simulations are used to update the MoC initial conditions and adjust the viscous boundary layer correction. The technique developed here preserves the simplicity and speed of method of characteristics nozzle design while capturing finite-rate vibrational processes and efficiently using RANS simulation results. We present several validation cases to demonstrate the method's accuracy in equilibrium and nonequilibrium cases. Finally, we detail the design of a Mach-8 nozzle which is currently under construction for the University of Maryland Hypersonic Aerodynamics and Propulsion (HAPL) laboratory.