Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage

1992 ◽  
Author(s):  
T. Green ◽  
A. B. Turner
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Computer Code ◽  
Rotor Blades ◽  
Rotor Speed ◽  
Turbine Stage ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Axial Clearance ◽  
Nozzle Guide

The upstream wheelspace of an axial air turbine stage complete with nozzle guide vanes (NGV’s) and rotor blades (430 mm mean diameter) has been tested with the objective of examining the combined effect of NGV’s and rotor blades on the level of mainstream ingestion for different seal flow rates. A simple axial clearance seal was used with the rotor spun up to 6650 rpm by drawing air through it from atmospheric pressure with a large centrifugal compressor. The effect of rotational speed was examined for several constant mainsteam flow rates by controlling the rotor speed with an air brake. The circumferential variation in hub static pressure was measured at the trailing edge of the NGV’s upstream of the seal gap and was found to significantly affect ingestion. The hub static pressure distribution on the rotor blade leading edges was rotor speed dependent and could not be measured in the experiments. The Denton 3D C.F.D. computer code was used to predict the smoothed time dependent pressure field for the rotor together with the pressure distribution downstream of the NGV’s. The level and distribution of mainstream ingestion, and thus the seal effectiveness, was determined from nitrous oxide gas concentration measurements and related to static pressure measurements made throughout the wheelspace. With the axial clearance rim seal close to the rotor the presence of the blades had a complex effect. Rotor blades in connection with NGV’s were found to significantly reduce mainstream ingestion seal flow rates, but a small level of ingestion existed even for very high levels of seal flow rate.

Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage

1994 ◽  
Vol 116 (2) ◽  
pp. 327-332 ◽  
Author(s):  
T. Green ◽  
A. B. Turner
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Three Dimensional ◽  
Computer Code ◽  
Rotor Blades ◽  
Rotor Speed ◽  
Turbine Stage ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Axial Clearance

The upstream wheelspace of an axial air turbine stage complete with nozzle guide vanes (NGVs) and rotor blades (430 mm mean diameter) has been tested with the objective of examining the combined effect of NGVs and rotor blades on the level of mainstream ingestion for different seal flow rates. A simple axial clearance seal was used with the rotor spun up to 6650 rpm by drawing air through it from atmospheric pressure with a large centrifugal compressor. The effect of rotational speed was examined for several constant mainstream flow rates by controlling the rotor speed with an air brake. The circumferential variation in hub static pressure was measured at the trailing edge of the NGVs upstream of the seal gap and was found to affect ingestion significantly. The hub static pressure distribution on the rotor blade leading edges was rotor speed dependent and could not be measured in the experiments. The Denton three-dimensional C.F.D. computer code was used to predict the smoothed time-dependent pressure field for the rotor together with the pressure distribution downstream of the NGVs. The level and distribution of mainstream ingestion, and thus the seal effectiveness, was determined from nitrous oxide gas concentration measurements and related to static pressure measurements made throughout the wheelspace. With the axial clearance rim seal close to the rotor the presence of the blades had a complex effect. Rotor blades in connection with NGVs were found to reduce mainstream ingestion seal flow rates significantly, but a small level of ingestion existed even for very high levels of seal flow rate.

Efficiency Improvements in an Industrial Steam Turbine Stage: Part 2

2016 ◽  
Author(s):  
Srikanth Deshpande ◽  
Marcus Thern ◽  
Magnus Genrup
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Flow Path ◽  
Total Efficiency ◽  
Leakage Flow ◽  
Turbine Stage ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Static Pressure Distribution ◽  
Path Modification

Improvement in isentropic total to total efficiency of a low reaction turbine stage by airfoil redesign was considered in first part of the paper. Further, modifications in the flow path of the baseline stage is considered in second part of the paper. Flow path of the baseline stage incorporates axisymmetric meridional endwall contour (commonly called Russian kink). For a stage comprising of high aspect ratio blades, assessment of performance with endwall contour is performed. Alternatives, if required for endwall contour had to be explored and numerically verified. Endeavor in the present paper is in this direction. Static pressure distribution at the stator exit is considered as the main objective. Along with flow path modification, stator modifications like vortexing and lean are attempted to obtain stator exit static pressure distribution similar to baseline case. Straight lean on stator provides good results in terms of reducing stator exit pressure gradient as well as reducing gradient of rotor inlet swirl. Since the pressure distribution at stator exit also drives the tip leakage flow, effect of flowpath and stator modifications on tip leakage flow is studied. Performance numbers are reported for cases with and without tip shroud.

Study of Semi-Inverse Problem for the Design of Annular S-Shaped Compressor Transition Duct

2015 ◽  
Author(s):  
Peng Shan ◽  
Jingyuan Wang ◽  
Zhentao Lv
Keyword(s):  
Inverse Problem ◽  
Pressure Distribution ◽  
Static Pressure ◽  
Pressure Coefficient ◽  
Optimal Solution ◽  
Outer Wall ◽  
Wall Pressure ◽  
Design Parameters ◽  
Gradient Distribution ◽  
Static Pressure Distribution

A new aerodynamic design strategy of the S-shaped transition duct between two compressor components was studied. Based on the controlled wall pressure gradient distribution and the wall velocity distribution, a semi-inverse problem of the transition duct was proposed, the corresponding inverse and direct approach codes were developed. To verify the feasibility of this method, two axial-centrifugal compressor transition ducts were designed. The results show that the static pressure distribution on the inner wall and the duct geometry both can be controlled freely by adjusting the inverse design parameters. The designed inner wall pressure distribution can be realized through a numerical matching procedure of the outer wall geometry based on the direct problem. The new design method is practicable that, without searching the optimal solution of the static pressure distribution of the inner wall, the total pressure coefficient can be at least 0.92.

Plantar Static Pressure Distribution in Healthy Individuals

2014 ◽  
Vol 7 (4) ◽  
pp. 293-297 ◽  
Author(s):  
David Pomarino ◽  
Andrea Pomarino
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Age Groups ◽  
Case Series ◽  
Load Sharing ◽  
Standing Position ◽  
Healthy Individuals ◽  
Static Pressure Distribution ◽  
Standard Values ◽  
The Right

In literature, one finds little scientific statements regarding plantar static pressure distribution in healthy individuals. Miscellaneous studies, however, characterize pathologies of feet and associate those with abnormal static or dynamic plantar load sharing. Our study reveals that healthy individuals show significant age-dependent differences in forefoot and rear foot load measured in standing position. The forefoot and rear foot load of 238 female and 193 male individuals aged between 2 and 69 years were measured. Using a pressure distribution measurement platform, the measurements were taken barefooted in standing position. Those measurements are presented as percentage of the overall load. The measurements within the age groups A1 (2-6 years), A2 (7-10 years), and A3 (11-69 years) showed significantly different forefoot loading means of the left foot (A1, 19.9%; A2, 28.2%; A3, 39.7%) and the right foot (A1, 22.6%; A2, 29.7%; A3, 39.6%). The forefoot loadings are graphically displayed as a function of the percentiles 5, 10, 25, 50, 75, 90, and 95. Forefoot loadings are referred to as “prominent” if the measured values lie off the interquartile range; if either below the percentile 10 or above 90 the loadings are referred to as “very prominent.” Our study contains significant data regarding the extent of the static load sharing of the forefoot and rear foot of healthy individuals; the data are suited for being standard values to evaluate plantar load sharing. Levels of Evidence: Diagnostic Level IV: Case series

Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage

2000 ◽  
Author(s):  
P. Giangiacomo ◽  
V. Michelassi ◽  
F. Martelli
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Turbine Stage ◽  
Flow Rates ◽  
Tip Leakage ◽  
Mass Flow Rates ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Rotor Mass

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.

Influence of Hot Streak Circumferential Length-Scale in Transonic Turbine Stage

2004 ◽  
Author(s):  
L. He ◽  
V. Menshikova ◽  
B. R. Haller
Keyword(s):  
Heat Transfer ◽  
Computational Study ◽  
Guide Vane ◽  
Strong Dependence ◽  
Rotor Blades ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Blade Vibration ◽  
Nozzle Guide ◽  
Hot Streak

A computational study is carried out on the influence of turbine inlet temperature distortion (hot streak). The hot streak effects are examined from both aeromechanical (forced blade vibration) and aero-thermal (heat transfer) points of view. Computations are firstly carried out for a transonic HP turbine stage, and the steady and unsteady surface pressure results are compared with the corresponding experimental data. Subsequent analysis is carried out for hot-streaks with variable circumferential wavelength, corresponding to different numbers of combustion burners. The results show that the circumferential wavelength of the temperature distortion can significantly change unsteady forcing as well as the heat-transfer to rotor blades. In particular, when the hot-streak wavelength is the same as the nozzle guide vane (NGV) blade pitch, there is a strong dependence of the preferential heating characteristics on the relative clocking position between hot-streak and NGV blade. However, this clocking dependence is shown to be qualitatively weakened for the cases with fewer hot streaks with longer circumferential wavelengths.

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