Time resolved pressure measurements by means of PSP in cryogenic conditions

2022 ◽  
Author(s):  
Christian Klein
Keyword(s):  
Pressure Measurements ◽  
Time Resolved ◽  
Cryogenic Conditions

Influence of a Cylindrical Exhaust Hood Installation on the Last Stage Rotor Blades of a Low Pressure Model Steam Turbine

2017 ◽  
Author(s):  
Fabian F. Müller ◽  
Markus Schatz ◽  
Damian M. Vogt ◽  
Jens Aschenbruck
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Pressure Measurements ◽  
Exhaust Hood ◽  
Blade Vibration ◽  
Time Resolved ◽  
Vibration Behavior ◽  
Last Stage

The influence of a cylindrical strut shortly downstream of the bladerow on the vibration behavior of the last stage rotor blades of a single stage LP model steam turbine was investigated in the present study. Steam turbine retrofits often result in an increase of turbine size, aiming for more power and higher efficiency. As the existing LP steam turbine exhaust hoods are generally not modified, the last stage rotor blades frequently move closer to installations within the exhaust hood. To capture the influence of such an installation on the flow field characteristics, extensive flow field measurements using pneumatic probes were conducted at the turbine outlet plane. In addition, time-resolved pressure measurements along the casing contour of the diffuser and on the surface of the cylinder were made, aiming for the identification of pressure fluctuations induced by the flow around the installation. Blade vibration behavior was measured at three different operating conditions by means of a tip timing system. Despite the considerable changes in the flow field and its frequency content, no significant impact on blade vibration amplitudes were observed for the investigated case and considered operating conditions. Nevertheless, time-resolved pressure measurements suggest that notable pressure oscillations induced by the vortex shedding can reach the upstream bladerow.

Unsteady pressure measurements by means of PSP in cryogenic conditions

2020 ◽  
Author(s):  
Christian Klein ◽  
Daisuke Yorita ◽  
Ulrich Henne ◽  
Tobias Kleindienst ◽  
Stefan Koch ◽  
...  
Keyword(s):  
Pressure Measurements ◽  
Unsteady Pressure ◽  
Unsteady Pressure Measurements ◽  
Cryogenic Conditions

Correlating Time-Resolved Pressure Measurements with Rim Sealing Effectiveness for Real-Time Turbine Health Monitoring

2021 ◽  
pp. 1-40
Author(s):  
Eric DeShong ◽  
Benjamin Peters ◽  
Reid A. Berdanier ◽  
Karen A. Thole ◽  
Kamran Paynabar ◽  
...  
Keyword(s):  
Real Time ◽  
Performance Feedback ◽  
Domain Knowledge ◽  
Performance Monitoring ◽  
Operating Conditions ◽  
Machine Learning Techniques ◽  
Pressure Measurements ◽  
Time Resolved ◽  
Learning Techniques ◽  
Purge Flow

Abstract Purge flow is bled from the upstream compressor and supplied to the under-platform region to prevent hot main gas path ingress that damages vulnerable under-platform hardware components. A majority of turbine rim seal research has sought to identify methods of improving sealing technologies and understanding the physical mechanisms that drive ingress. While these studies directly support the design and analysis of advanced rim seal geometries and purge flow systems, the studies are limited in their applicability to real-time monitoring required for condition-based operation and maintenance. As operational hours increase for in-service engines, this lack of rim seal performance feedback results in progressive degradation of sealing effectiveness, thereby leading to reduced hardware life. To address this need for rim seal performance monitoring, the present study utilizes measurements from a one-stage turbine research facility operating with true-scale engine hardware at engine-relevant conditions. Time-resolved pressure measurements collected from the rim seal region are regressed with sealing effectiveness through the use of common machine learning techniques to provide real-time feedback of sealing effectiveness. Two modelling approaches are presented that use a single sensor to predict sealing effectiveness accurately over a range of two turbine operating conditions. Results show that an initial purely data-driven model can be further improved using domain knowledge of relevant turbine operations, which yields sealing effectiveness predictions within three percent of measured values.

Time-Resolved PIV and Pressure Measurements of Oscillating and Pulsating Flow in a Rapid Expansion

2007 ◽  
Author(s):  
Barton L. Smith ◽  
Cameron V. King
Keyword(s):  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Pulsating Flow ◽  
Displacement Amplitude ◽  
Rapid Expansion ◽  
Pressure Measurements ◽  
Time Resolved ◽  
Separated Shear Layer ◽  
Minor Losses ◽  
Pressure And Velocity Measurements

Separating oscillating and pulsating flows in an internal adverse pressure gradient geometry are studied experimentally. Time-resolved PIV measurements and simultaneous pressure measurements reveal that, in oscillating flow, during the accelerating portion of the cycle, the flow remains attached in spite of a very large adverse pressure gradient. During the decelerating portion of the cycle, the flow is more prone to separation. The duration and extent of the separation depend strongly on the oscillation displacement amplitude relative to the cross-stream dimension. In some cases, the flow separates but reattaches as the separated shear layer is accelerated temporally. The time-varying pressure measurements are used to determine the resultant minor losses for the flow in each direction. These are found to be an increasing function of displacement amplitude and a decreasing function of the Reynolds number and can be greater than or less than those for steady flow. Pressure and velocity measurements are presented for pulsating flow with various DC components.

Aero-Micro-Electromechanical System Sensor Arrays for Time Resolved Wall Pressure Measurements

AIAA Journal ◽  
2009 ◽  
Vol 47 (4) ◽  
pp. 863-873 ◽  
Author(s):  
A. Berns ◽  
U. Buder ◽  
E. Obermeier ◽  
A. Wolter ◽  
A. Leder ◽  
...  
Keyword(s):  
Sensor Arrays ◽  
Wall Pressure ◽  
Electromechanical System ◽  
Pressure Measurements ◽  
Time Resolved ◽  
Micro Electromechanical System

Analysis of Axial Compressor Stall Inception Using Unsteady Casing Pressure Measurements

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Joshua D. Cameron ◽  
Scott C. Morris
Keyword(s):  
Pressure Sensors ◽  
Axial Compressor ◽  
Leading Edge ◽  
Scalar Function ◽  
Pressure Measurements ◽  
Time Resolved ◽  
Fourier Decomposition ◽  
Stall Inception ◽  
Axial Compressors ◽  
Casing Pressure

The unsteady flow in axial compressors during pre-stall and stall inception is often studied using circumferentially distributed pressure sensors. The present investigation utilized a transonic axial compressor facility to acquire time resolved casing static pressure measurements at an axial location upstream of the rotor leading edge. These measurements were processed using a variety of analysis techniques in order to provide insight into the fluid dynamics and compression system dynamics prior to and during stall inception. Specifically, visual inspection of the time series, spatial Fourier decomposition, traveling wave energy, and wavelet transform results will be described and compared for two representative stall inception events. Additionally, a new method was developed based on a windowed, two-point correlation function between adjacent sensors. The intent was to provide a scalar function that was nonzero only when disturbances that rotated around the compressor annulus in the direction of the rotor’s rotation were present. The results indicated that this method highlights many detailed features of the rotating disturbances with both spatial and temporal resolution during both pre-stall and stall inception.

Multi-Time-Delay LSE-POD Complementary Approach Applied to Wake Flow Behind a Bluff Body

2007 ◽  
Author(s):  
Vibhav Durgesh ◽  
Jonathan W. Naughton
Keyword(s):  
Time Delay ◽  
Surface Pressure ◽  
Bluff Body ◽  
Wake Flow ◽  
Time Varying ◽  
Pressure Measurements ◽  
Near Wake ◽  
Time Resolved ◽  
Complementary Approach ◽  
The Time Domain

An understanding of the near wake dynamics of a bluff body is desired to better link base drag reduction observed on these bodies with the coherent structures in the wake. This investigation explores different Linear Stochastic Estimation-Proper Orthogonal Decomposition (LSE-POD) methods that can be employed to estimate the dynamics of the energy containing structure. Statistically independent two-dimensional PIV measurements and time-resolved surface pressure measurements are used to determine spatial POD modes and LSE coefficients for estimating the time-varying POD coefficients using measured surface pressures. These results are used with the time-resolved surface pressure measurements to estimate the time-varying POD coefficients that may be used for a low-order, time-resolved reconstruction of the flow field. The multi-time LSE approach formulated in the time domain (multi-time-delay LSE) is found to be successful in capturing the important near wake dynamics.

Correlating Time-Resolved Pressure Measurements With Rim Sealing Effectiveness for Real-Time Turbine Health Monitoring

2021 ◽  
Author(s):  
Eric T. DeShong ◽  
Benjamin Peters ◽  
Reid A. Berdanier ◽  
Karen A. Thole ◽  
Kamran Paynabar ◽  
...  
Keyword(s):  
Real Time ◽  
Performance Feedback ◽  
Domain Knowledge ◽  
Performance Monitoring ◽  
Operating Conditions ◽  
Machine Learning Techniques ◽  
Pressure Measurements ◽  
Time Resolved ◽  
Learning Techniques ◽  
Purge Flow

Abstract Purge flow is bled from the upstream compressor and supplied to the under-platform region to prevent hot main gas path ingress that damages vulnerable under-platform hardware components. A majority of turbine rim seal research has sought to identify methods of improving sealing technologies and understanding the physical mechanisms that drive ingress. While these studies directly support the design and analysis of advanced rim seal geometries and purge flow systems, the studies are limited in their applicability to real-time monitoring required for condition-based operation and maintenance. As operational hours increase for in-service engines, this lack of rim seal performance feedback results in progressive degradation of sealing effectiveness, thereby leading to reduced hardware life. To address this need for rim seal performance monitoring, the present study utilizes measurements from a one-stage turbine research facility operating with true-scale engine hardware at engine-relevant conditions. Time-resolved pressure measurements collected from the rim seal region are regressed with sealing effectiveness through the use of common machine learning techniques to provide real-time feedback of sealing effectiveness. Two modelling approaches are presented that use a single sensor to predict sealing effectiveness accurately over a range of two turbine operating conditions. Results show that an initial purely data-driven model can be further improved using domain knowledge of relevant turbine operations, which yields sealing effectiveness predictions within three percent of measured values.

Sign in / Sign up

Export Citation Format

Share Document