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.

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.

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.

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.

Numerical Simulation of Three Dimensional Flow in Large Mixed-Flow Pump System

2011 ◽  
Author(s):  
Fan Yang ◽  
Chao Liu ◽  
Fangping Tang
Keyword(s):  
Pressure Distribution ◽  
Model Test ◽  
Static Pressure ◽  
Three Dimensional ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Static Pressure Distribution ◽  
Calculation Results ◽  
Flow Pump

The three-dimensional flow inside a mixed-flow pump system was simulated by using CFX software. The Shear Stress Transport turbulent equation which combined k-ε and k-ω turbulent model was applied. The flow field in volute and discharge passage of the pump system was obtained and the hydraulic performances of the pump system were predicted. The velocity and pressure distribution in pump system were analyzed. From the calculation results it is evident that the flow in the double helix volute passage is a spiral movement combining axial and rotary flow; the static pressure distribution in the volute is symmetric; the uniformity of axial velocity distribution and velocity-weighted average swirl angle at the outlet section are relatively low; and static pressure distribution on pump blade surface is regular with higher static pressure on pressure side and lower one on the suction side. The axial forces decrease gradually with the decrease of lifting head and the radial forces decrease first and then increase. A model test of the pump system was conducted to verify the calculation results. The pressure fluctuation at certain sections of the pump system was measured from the model test. A good agreement was found for lifting head between calculated and measured results. While the deviation of the efficiency between calculated and measured results does exist in non design points which need to be improved.

A New Three-Dimensional Viscous Inverse Design Method for Axial Compressor Blade

2016 ◽  
Author(s):  
Zhaowei Liu ◽  
Hu Wu
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Design Method ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design Procedure ◽  
Inverse Design ◽  
Blade Surface ◽  
Static Pressure Distribution ◽  
Inverse Design Method

A recently developed aerodynamic inverse design method for axial compressor is presented in this paper. The inverse design method is based on solving the three-dimensional Reynolds-averaged Navier-Stokes equations. Blade surface static pressure distribution is prescribed before the design procedure. A new inverse design boundary condition is established based on the conservation of Riemann invariant on the blade surface. Blade profile is constantly modified by a virtual wall velocity which is obtained from the difference between the current and prescribed static pressure. The dynamic mesh theory is used to update the computation mesh where the shape of the blade is changing during the design process. The design procedure finishes after the prescribed static pressure distribution on the blade surface is satisfied. The method is first validated by a blade recovery test. It is then used to redesign the NASA Rotor 67.

Effects of Stator Wakes and Spanwise Nonuniform Inlet Conditions on the Rotor Flow of an Axial Turbine Stage

1993 ◽  
Vol 115 (1) ◽  
pp. 128-136 ◽  
Author(s):  
J. Zeschky ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Hot Wire ◽  
Turbine Stage ◽  
Static Pressure Distribution ◽  
Inlet Conditions ◽  
Experimental Values ◽  
Rotor Flow

Detailed measurements have been performed in a subsonic, axial-flow turbine stage to investigate the structure of the secondary flow field and the loss generation. The data include the static pressure distribution on the rotor blade passage surfaces and radial-circumferential measurements of the rotor exit flow field using three-dimensional hot-wire and pneumatic probes. The flow field at the rotor outlet is derived from unsteady hot-wire measurements with high temporal and spatial resolution. The paper presents the formation of the tip clearance vortex and the passage vortices, which are strongly influenced by the spanwise nonuniform stator outlet flow. Taking the experimental values for the unsteady flow velocities and turbulence properties, the effect of the periodic stator wakes on the rotor flow is discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document