Research Areas‎ > ‎

Hypersonics


Key Personnel


  • Sergey Leonov
  • Thomas Juliano
  • Thomas Corke
  • Flint Thomas
Overview
The effective operation of high-speed air-breathing engines (ram and scram-jets) over a wide range of flow parameters (velocity and altitude) is one of the most technically difficult challenges in design of hypersonic vehicles. The promising approach is a scram-jet having flexible gas dynamic configurations that meets a number of extremely challenging technical issues: materials, gears, etc. Commonly discussed trade-off assessment consists of a fixed geometrical configuration based on some ‘characteristic’ Mach number of operation and a control system augmenting a poorer performance for lower and higher values of Mach number, especially for ram/scram transition mode.

To improve the overall capability of a scram-jet with fixed duct geometry at variable conditions, some methods could be applied such as a staged fuel injection, additional mechanical flame holding, or electrical discharge as an ignitor and flame holder. The main advantage of plasma application for control of fuel ignition/combustion is due to non-equilibrium, non-uniform and transient nature of electrical discharges, which deliver a synergy with thermal effects (heating) owing to essentially nonlinear behavior of induction time versus gas temperature. Those properties may also be of critical importance under non-premixed flow conditions, enhancing air–fuel mixing in compressible flows.

Three main ideas underlie the concept of plasma-assisted combustion:
  1.   The gas heating/non-equilibrium excitation by the discharge.
  2.   Fuel–air mixing enhancement owing to gas dynamic instability generation.
  3.   Control of flow structure in the vicinity of the reaction zone.


High Enthalpy Arc Tunnel

The University of Notre Dame's High-Enthalpy Arc-heated Tunnel (HEAT) is a pulsed hypersonic wind tunnel operative since 2013, that can produce Mach 6 flows in the low to medium Reynolds number range (104 -106 ). In the wind tunnel settling chamber the gas is heated by means of an arc discharge powered by a 250 kW DC power supply and delivering arc currents up to 630 A with running times of 20-300 ms. The gas heater can be operated with air, nitrogen, argon, and CO2 in a pulsed or quasi-steady mode.























Supersonic Blowdown Test Rig  (SBR-50)
The SBR-50 is an inline supersonic test facility capable of Mach numbers 2, 4, and 6 with a run time of 1 to 3 seconds.  The purpose of the facility is the study of multi-stage mechanism of supersonic plasma assisted combustion as well as the experimental verification of the Plasma Injection Module concept. 
The SBR-50 is also well suited to understanding how flow turbulence effects super sonic ignition and flame-holding in a cavity or plane wall. 






Future Expansion
Mach 6 Quiet Ludweig Tube Facility

The operation of the Ludwieg Tube starts when the twin 40,000 gallon dump tanks, nozzle, and test section are evacuated and the 200 foot long driver tube is pressurized to the desired fill pressure. A fast acting valve is opened to start the run. When the valve opens a weak shock propagates into the dump tank and a non steady expansion wave propagates upstream into the driver tube. The expansion wave sets up steady flow through the nozzle and test section until the wave returns to the entrance of the nozzle after reflecting off of the driver tube end-wall.




Comments