Centre for Hypersonics

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The Drummond Tunnel is a small shock tunnel used for testing at velocities of the order of 2 km/s.

Specifications
  • Shock tube: 3 m long x 62 mm diameter
  • Nozzles:
    • Conical Mach 4
    • Conical Mach 7
    • Contoured Mach 7 
  • Typical operating conditions with He driving Air:
    • Supply enthalpy = 2 MJ/kg
    • Supply pressure = 2.2 MPa

This tunnel consists of a high pressure chamber and a low pressure chamber separated by an aluminium diaphragm. When the diaphragm is ruptured, a shock wave is driven through the lower pressure (test) gas which is thereby compressed and accelerated. When operated as a shock tube, optical access is obtained through four windows positioned near the end of the tube within which the model is mounted. For operation as a shock tunnel, a nozzle is attached to the end of the tube and optical access obtained through windows mounted in the dump tank. In each case the test time is of the order of several hundred microseconds. The test section has good optical access with four 100 mm diameter quartz windows.

Typical flow conditions achieved assuming equilibrium chemistry:

Parameter

Tube
Tunnel
Free-stream
Normal Shock
Freestream
Normal Shock

Pressure (kPa)

79
310
16.8
320

Temperature (K)

2270
3000
495
1820

Density (kg/m3)

0.12
0.35
0.12
0.61

Enthalpy (MJ/kg)

3.7
3.7
1.8
1.8

Velocity (km/s)

1.7
0.58
1.8
0.34

Mach Number

1.8
0.54
4.0
0.42

Diss. fraction N2

-
-
-
-

Diss. fraction O2

-
0.08
-
-

%NO

-
4.1
-
0.4

Ion. fraction N

-
-
-
-

Ion. fraction O

-
-
-
-

 

 

Schematic of the Drummond Tunnel

 

Drummond Tunnel Manual