Evaluation of unsteady pressure fields and forces in rotating airfoils from time-resolved PIV

The radial gap between the impeller tips and volute tongue is an important factor influencing the overall performance and unsteady pressure fields of the pump as turbine (PAT). In this paper, a numerical investigation of the PAT's steady performance with different radial gaps was first performed. The results show that there is an optimal radial gap for a PAT to achieve its highest efficiency. An analysis of the PAT's unsteady pressure fields indicates that the rotorstator interaction of a rotating impeller and stationery volute would cause high frequency unsteady pulsation within the volute and low frequency unsteady pressure pulsation within the impeller. The high frequency unsteady pressure pulsation would propagate through the PAT's flow channel. Thus, the unsteady pressure field within the impeller is the combined effect of these two kinds of pressure pulsations. The unsteady pressure pulsation within the outlet pipe is mainly caused by the propagation of unsteady pressure formed within the volute. With the increase of the radial gap, the amplitude of high frequency unsteady pressure pulsation within the volute caused by the rotor-stator interaction is decreased, while the amplitude of the low frequency unsteady pressure pulsation caused by the rotor-stator interaction within the impeller remains unchanged.

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Assessment of the pseudo-tracking approach for the calculation of material acceleration and pressure fields from time-resolved PIV: part II. Spatio-temporal filtering

Measurement Science and Technology ◽

10.1088/1361-6501/aaab84 ◽

2018 ◽

Vol 29 (4) ◽

pp. 045206 ◽

Cited By ~ 3

Author(s):

P L van Gent ◽

F F J Schrijer ◽

B W van Oudheusden

Keyword(s):

Time Resolved ◽

Temporal Filtering ◽

Pressure Fields ◽

Spatio Temporal

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Past Developments and Current Advancements in Unsteady Pressure Measurements in Turbomachines

Journal of Turbomachinery ◽

10.1115/1.4040419 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 3

Author(s):

Jan Lepicovsky ◽

David Simurda

Keyword(s):

Pressure Measurement ◽

High Speed ◽

Measurement Techniques ◽

Fast Response ◽

Future Research ◽

Flow Measurements ◽

Time Resolved ◽

Turbine Engine ◽

Pressure Transducers ◽

Unsteady Pressure

The aim of this paper is to review, summarize, and record long-term experience with development and application of aerodynamic probes with built-in miniature pressure transducers for unsteady pressure measurement and industrial research in turbomachine components. The focus of the first half of the paper is on the work performed at VZLU Prague, Czech Republic (Secs. 3–8). The latest development in unsteady pressure measurement techniques and data reduction methodology suitable for future research in highly loaded, high-speed turbine engine components performed at NASA GRC Cleveland, OH, is reported in Secs. 8–15 of this paper. Excellent reviews of similar activities at ETH Zürich, Switzerland by Kupferschmied, et al. (2000, “Time-Resolved Flow Measurements With Fast-Response Aerodynamic Probes in Turbomachines,” Meas. Sci. Technol., 11(7), pp. 1036–1054) and at VKI Rhode-Sain-Genèse, Belgium by Sieverding, et al. (2000, “Measurement Techniques for Unsteady Flows in Turbomachines,” Exp. Fluids, 28(4), pp. 285–321) were already reported and are acknowledged here. A short list of reported accomplishments achieved by other researchers at various laboratories is also reported for completeness. The authors apologize to those whose contributions are not reported here. It is just an unfortunate oversight, not an intentional omission.

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Wake, Shock, and Potential Field Interactions in a 1.5 Stage Turbine—Part I: Vane-Rotor and Rotor-Vane Interaction

Journal of Turbomachinery ◽

10.1115/1.1508386 ◽

2003 ◽

Vol 125 (1) ◽

pp. 33-39 ◽

Cited By ~ 29

Author(s):

R. J. Miller ◽

R. W. Moss ◽

R. W. Ainsworth ◽

N. W. Harvey

Keyword(s):

High Pressure ◽

Potential Field ◽

Pressure Field ◽

Fast Response ◽

Operating Conditions ◽

Rotor Blades ◽

Time Resolved ◽

Pressure Transducers ◽

Unsteady Pressure ◽

The Individual

The composition of the time-resolved surface pressure field around a high-pressure rotor blade caused by the presence of neighboring blade rows is investigated, with the individual effects of wake, shock and potential field interaction being determined. Two test geometries are considered: first, a high-pressure turbine stage coupled with a swan-necked diffuser exit duct; secondly, the same high-pressure stage but with a vane located in the downstream duct. Both tests were conducted at engine-representative Mach and Reynolds numbers, and experimental data was acquired using fast-response pressure transducers mounted on the mid-height streamline of the HP rotor blades. The results are compared to time-resolved computational predictions of the flowfield in order to aid interpretation of experimental results and to determine the accuracy with which the computation predicts blade interaction. The paper is split into two parts: the first investigating the effect of the upstream vane on the unsteady pressure field around the rotor (vane-rotor interaction), and the second investigating the effect of the downstream vane on the unsteady pressure field around the rotor (rotor-vane interaction). The paper shows that at typical design operating conditions shock interaction from the upstream blade row is an order of magnitude greater than wake interaction and that with the design vane-rotor inter-blade gap the presence of the rotor causes a periodic increase in the strength of the vane trailing edge shock. The presence of the potential field of the downstream vane is found to affect significantly the rotor pressure field downstream of the Mach one surface within each rotor passage.

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