Transonic Calibration Tunnel

Investigators: Professor Tom Povey, Ben Hall

The transonic calibration facility was commissioned in the period 2010-2015 and now provides fully automated, high accuracy calibrations of probes for turbomachinery applications. The Mach number range is 0 to 1.9, and the tunnel spans a Reynolds number range greater than that normally encountered in turbomachinery applications in industry. The 4" (100 mm) diameter nozzle allows large probes to be accommodated, such as rakes of multi-hole probes for combustor exit survey applications.













By employing an annular sector of deswirl vanes downstream of the annular sector of test vanes, the radial pressure gradient established in the swirling flow downstream of the test vanes is not disturbed. The deswirl vane exit-flow – which has zero swirl velocity – can be exhausted without unsteadiness, and without the risk of separation, into a plenum at constant pressure. The pressure ratio across the annular sector of test vanes can be tuned by adjusting the throat area at the deswirl vane exit plane.

Schematic of the Annular Sector FacilityFlow conditioning systems which utilise the Oxford deswirl vane technology have previously been used to set pressure boundary conditions downstream of fully annular cascades in both model and engine-scale (the Isentropic Light Piston Facility at Farnborough) experimental research facilities.

The deswirl vane is particularly suited to the control of highly whirling transonic flows. It has been demonstrated by direct comparison of aerodynamic measurements from fully annular and annular sector experiments that the use of a deswirl vane sector for flow conditioning at the exit of