Unsteady Pressure Measurements on Rotor Blade Tips with Incidence

AIAA Journal ◽  
1979 ◽  
Vol 17 (5) ◽  
pp. 514-518
Author(s):  
Hermann Triebstein
Keyword(s):  
Rotor Blade ◽  
Pressure Measurements ◽  
Unsteady Pressure ◽  
Unsteady Pressure Measurements ◽  
Blade Tips

Effect of back pressure and freestream dynamic pressure on a typical Ramjet engine duct under realistic supersonic inlet condition

2017 ◽  
Vol 122 (1247) ◽  
pp. 83-103 ◽  
Author(s):  
R. Saravanan ◽  
S.L.N. Desikan ◽  
T.M. Muruganandam
Keyword(s):  
Dynamic Pressure ◽  
Back Pressure ◽  
Flow Visualisation ◽  
Pressure Measurements ◽  
Shock Train ◽  
Unsteady Pressure ◽  
Expansion Waves ◽  
Ramjet Engine ◽  
Flap Deflection ◽  
Unsteady Pressure Measurements

ABSTRACTThe present study investigates the behaviour of the shock train in a typical Ramjet engine under the influence of shock and expansion waves at the entry of a low aspect ratio (1:0.75) rectangular duct/isolator at supersonic Mach number (M = 1.7). The start/unstart characteristics are investigated through steady/unsteady pressure measurements under different back and dynamic pressures while the shock train dynamics are captured through instantaneous Schlieren flow visualisation. Two parameters, namely pressure recovery and the pressure gradient, is derived to assess the duct/isolator performance. For a given back pressure, with maximum blockage (9% above nominal), the duct/isolator flow is established when the dynamic pressure is increased by 23.5%. The unsteady pressure measurements indicate different scales of eddies above 80 Hz (with and without flap deflection). Under the no flap deflection (no back pressure) condition, the maximum fluctuating pressure component is 0.01% and 0.1% of the stagnation pressure at X/L = 0.03 (close to the entry of the duct) and X/L = 0.53 (middle of the duct), respectively. Once the flap is deflected (δ = 8°), decay in eddies by one order is noticed. Further increase in back pressure (δ ≥ 11°) leads the flow to unstart where eddies are observed to be disappeared.

Unsteady Pressure Measurements in a Heated Rotating Cavity

2021 ◽  
Author(s):  
Richard W. Jackson ◽  
Hui Tang ◽  
James A. Scobie ◽  
Oliver J. Pountney ◽  
Carl M. Sangan ◽  
...  
Keyword(s):  
Vortex Pair ◽  
Practical Significance ◽  
Pressure Measurements ◽  
Rotating Disc ◽  
Frequency Spectra ◽  
Paper Properties ◽  
Unsteady Pressure ◽  
Rotating Cavity ◽  
Buoyancy Forces ◽  
Unsteady Pressure Measurements

Abstract The flow in the heated rotating cavity of an aero-engine compressor is driven by buoyancy forces, which result in pairs of cyclonic and anticyclonic vortices. The resultant cavity flow field is three-dimensional, unsteady and unstable, which makes it challenging to model the flow and heat transfer. In this paper, properties of the vortex structures are determined from novel unsteady pressure measurements collected on the rotating disc surface over a range of engine-representative parameters. These measurements are the first of their kind with practical significance to the engine designer and for validation of computational fluid dynamics. One cyclonic/anticyclonic vortex pair was detected over the experimental range, despite the measurement of harmonic modes in the frequency spectra at low Rossby numbers. It is shown that these modes were caused by unequal size vortices, with the cyclonic vortex the larger of the pair. The structures slipped relative to the discs at a speed typically around 10% to 15% of that of the rotor, but the speed of precession was often unsteady. The coherency, strength and slip of the vortex pair increased with the buoyancy parameter, due to the stronger buoyancy forces, but they were largely independent of the rotational Reynolds number.

Unsteady Aerodynamics and Interactions Between a High Pressure Turbine Vane and Rotor

2004 ◽  
Author(s):  
Ryan M. Urbassik ◽  
J. Mitch Wolff ◽  
Marc D. Polanka
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Potential Field ◽  
Rotor Blade ◽  
Second Harmonic ◽  
Unsteady Aerodynamics ◽  
Pressure Measurements ◽  
High Pressure Turbine ◽  
Turbine Vane ◽  
Unsteady Pressure Measurements

A set of experimental data is presented investigating the unsteady aerodynamics associated with a high pressure turbine vane (HPV) and rotor blade (HPB). The data was acquired at the Turbine Research Facility (TRF) of the Air Force Research Laboratory. The TRF is a transient, blowdown facility generating several seconds of experimental data on full scale engine hardware at scaled turbine operating conditions simulating an actual engine environment. The pressure ratio and freestream Reynolds number were varied for this investigation. Surface unsteady pressure measurements on the HPV, total pressure traverse measurements downstream of the vane, and surface unsteady pressure measurements for the rotor blade were obtained. The unsteady content of the HPV surface was generated by the rotor potential field. The first harmonic decayed more rapidly than the second harmonic with a movement upstream causing the second harmonic to be most influential at the vane throat. The blade unsteadiness appears to be caused by a combination of shock, potential field, and vane wake interactions between the vane and rotor blade. The revolution averaged data resulted in higher unsteadiness than a passing ensemble average for both vane and rotor indicating a need to understand each passage for high cycle fatigue (HCF) effects.

Wind tunnel unsteady pressure measurements using a differential optical fiber Fabry-Perot pressure sensor

2014 ◽  
Author(s):  
Ricardo Correia ◽  
Stephen E. Staines ◽  
Stephen W. James ◽  
Nicholas Lawson ◽  
Kevin Garry ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Optical Fiber ◽  
Pressure Sensor ◽  
Pressure Measurements ◽  
Unsteady Pressure ◽  
Fabry Perot ◽  
Unsteady Pressure Measurements
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