Transonic Turbine Stage Heat Transfer Investigation in Presence of Strong Shocks

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
A. de la Loma ◽  
G. Paniagua ◽  
D. Verrastro ◽  
P. Adami
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Shock Interaction ◽  
Turbine Stage ◽  
Test Rig ◽  
Unsteady Heat Transfer ◽  
Tube Test ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Layered Thin Film

This paper reports the external convective heat transfer distribution of a modern single-stage transonic turbine together with the physical interpretation of the different shock interaction mechanisms. The measurements have been performed in the compression tube test rig of the von Karman Institute using single- and double-layered thin film gauges. The three pressure ratios tested are representative of those encountered in actual aeroengines, with M2,is ranging from 1.07 to 1.25 and a Reynolds number of about 106. Three different rotor blade heights (15%, 50%, and 85%) and the stator blade at midspan have been investigated. The measurements highlight the destabilizing effect of the vane left-running shock on the rotor boundary layer. The stator unsteady heat transfer is dominated by the fluctuating right-running vane trailing edge shock at the blade passing frequency.

Transonic Turbine Stage Heat Transfer Investigation in Presence of Strong Shocks

2007 ◽  
Author(s):  
A. de la Loma ◽  
G. Paniagua ◽  
D. Verrastro ◽  
P. Adami
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Turbine Stage ◽  
Test Rig ◽  
Unsteady Heat Transfer ◽  
Tube Test ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Aero Engines ◽  
Layered Thin Film

This paper reports the external convective heat transfer distribution of a modern single-stage transonic turbine together with the physical interpretation of the different shock interaction mechanisms. The measurements have been performed in the compression tube test rig of the von Karman Institute using single and double-layered thin film gauges. The three pressure ratios tested are representative of those encountered in actual aero-engines, with M2, is ranging from 1.07 to 1.25 and a Reynolds number of about 106. Three different rotor blade heights (15%, 50% and 85%) and the stator blade at mid-span have been investigated. The measurements highlight the destabilizing effect of the vane left running shock on the rotor boundary layer. The stator unsteady heat transfer is dominated by the fluctuating right running vane trailing edge shock at the blade passing frequency.

scholarly journals Unsteady Flow in a Single Stage Turbine

1998 ◽  
Author(s):  
Mary A. Hilditch ◽  
Graham C. Smith ◽  
Udai K. Singh
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Pressure Fluctuations ◽  
Pressure Waves ◽  
Turbine Stage ◽  
Unsteady Heat Transfer ◽  
High Pressure Turbine ◽  
Suction Surface ◽  
Pressure Surface ◽  
Wake Interaction

This paper presents unsteady pressure and heat transfer measurements made on a high pressure turbine stage at DERA Pyestock, and compares them with numerical simulations made using the 2D unsteady code UNSFLO. The aim of the work was to evaluate the performance of the code, and to use the predictions to allow a fuller interpretation of the flow physics than could have been achieved from the measurements alone. The unsteady heat transfer and pressure fluctuations around the mid height section of the rotor blade have been examined in detail. Agreement between measured and predicted pressure fluctuations on the rotor was excellent. Interaction with the ngv potential field dominated the pressure surface, while the suction surface showed pressure waves moving forward over the blade, possibly as a result of shock/wake interaction.

Unsteady Heat Transfer in Stator–Rotor Interaction by Two-Equation Turbulence Model

1999 ◽  
Vol 121 (3) ◽  
pp. 436-447 ◽  
Author(s):  
V. Michelassi ◽  
F. Martelli ◽  
R. De´nos ◽  
T. Arts ◽  
C. H. Sieverding
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Rotor Blade ◽  
Two Dimensions ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Pressure Losses ◽  
Transonic Turbine ◽  
Variable Operating Conditions

A transonic turbine stage is computed by means of an unsteady Navier–Stokes solver. A two-equation turbulence model is coupled to a transition model based on integral parameters and an extra transport equation. The transonic stage is modeled in two dimensions with a variable span height for the rotor row. The analysis of the transonic turbine stage with stator trailing edge coolant ejection is carried out to compute the unsteady pressure and heat transfer distribution on the rotor blade under variable operating conditions. The stator coolant ejection allows the total pressure losses to be reduced, although no significant effects on the rotor heat transfer are found both in the computer simulation and the measurements. The results compare favorably with experiments in terms of both pressure distribution and heat transfer around the rotor blade.

Influence of the Radial Gap under the Stator Blade on Flow Around the Hub-End of the Rotor Blade

2016 ◽  
Vol 821 ◽  
pp. 120-128 ◽  
Author(s):  
Petr Straka ◽  
Martin Němec
Keyword(s):  
Experimental Data ◽  
Rotor Blade ◽  
Radial Clearance ◽  
Turbine Stage ◽  
Test Rig ◽  
Sliding Mesh ◽  
Linear Probe ◽  
Stator Blade ◽  
Brake Dynamometer ◽  
Radial Gap

This article deals with experimental and numerical investigation of flow in an axial turbine stage with prismatic blades which are not equipped with the shroud.Main attention is paid to explain the influence of the radial clearance under the stator blade on the flow around the rotor blade.The experiment was performed on the test rig equipped with the water brake dynamometer, torque meter and rotatable stator together with the linear probe manipulator.Numerical modelling was carried out for the unsteady flow using the ``sliding mesh'' interface between the stator and rotor wheels.Results of the numerical simulation are compared with the experimental data.

scholarly journals Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage

2010 ◽  
Author(s):  
Vikram Shyam ◽  
Ali Ameri ◽  
Jen-Ping Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Rotor Blade ◽  
High Speed ◽  
Pressure Ratio ◽  
Stagnation Temperature ◽  
Turbine Stage ◽  
Transonic Turbine ◽  
Highly Loaded

In a previous study, vane-rotor shock interactions and heat transfer on the rotor blade of a highly loaded transonic turbine stage were simulated. The geometry consists of a high pressure turbine vane and downstream rotor blade. This study focuses on the physics of flow and heat transfer in the rotor tip, casing and hub regions. The simulation was performed using the URANS (Unsteady Reynolds-Averaged Navier-Stokes) code MSU-TURBO. A low Reynolds number k-ε model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1% of the blade height. The Reynolds number of the flow is approximately 3×106 per meter. Unsteadiness was observed at the tip surface that results in intermittent ‘hot spots’. It is demonstrated that unsteadiness in the tip gap is governed by inviscid effects due to high speed flow and is not strongly dependent on pressure ratio across the tip gap contrary to published observations that have primarily dealt with subsonic tip flows. The high relative Mach numbers in the tip gap lead to a choking of the leakage flow that translates to a relative attenuation of losses at higher loading. The efficacy of new tip geometry is discussed to minimize heat flux at the tip while maintaining choked conditions. In addition, an explanation is provided that shows the mechanism behind the rise in stagnation temperature on the casing to values above the absolute total temperature at the inlet. It is concluded that even in steady mode, work transfer to the near tip fluid occurs due to relative shearing by the casing. This is believed to be the first such explanation of the work transfer phenomenon in the open literature. The difference in pattern between steady and time-averaged heat flux at the hub is also explained.

scholarly journals An Experimental Study of Film Cooling in a Rotating Transonic Turbine

1992 ◽  
Author(s):  
Reza S. Abhari ◽  
A. H. Epstein
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Test Facility ◽  
Turbine Stage ◽  
Unsteady Heat Transfer ◽  
Suction Surface ◽  
Time Resolved ◽  
Pressure Surface ◽  
Transonic Turbine ◽  
Time Resolved Measurements

Time-resolved measurements of heat transfer on a fully cooled transonic turbine stage have been taken in a short duration turbine test facility which simulates full engine non-dimensional conditions. The time average of this data is compared to uncooled rotor data and cooled linear cascade measurements made on the same profile. The film cooling reduces the time-averaged heat transfer compared to the uncooled rotor on the blade suction surface by as much as 60%, but has relatively little effect on the pressure surface. The suction surface rotor heat transfer is lower than that measured in the cascade. The results are similar over the central 3/4 of the span implying that the flow here is mainly two-dimensional. The film cooling is shown to be much less effective at high blowing ratios than at low ones. Time-resolved measurements reveal that the cooling, when effective, both reduced the d.c. level of heat transfer and changed the shape of the unsteady waveform. Unsteady blowing is shown to be a principal driver of film cooling fluctuations, and a linear model is shown to do a good job in predicting the unsteady heat transfer. The unsteadiness results in a 12% decrease in heat transfer on the suction surface and a 5% increase on the pressure surface.

Influence of the Hub Endwall Cavity Flow on the Time-Averaged and Time-Resolved Aero-Thermodynamics of an Axial HP Turbine Stage

2002 ◽  
Author(s):  
R. De´nos ◽  
G. Paniagua
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Significant Influence ◽  
Total Pressure ◽  
Rotor Blade ◽  
Static Pressure ◽  
Cavity Flow ◽  
Turbine Stage ◽  
Time Resolved ◽  
Transonic Turbine

This experimental research investigates the influence of the hub endwall cavity flow on the aerodynamics and heat transfer of a high-pressure transonic turbine stage tested under engine representative conditions. The measurements include the hub and tip endwall static pressure downstream of the vane, the static pressure and heat transfer on the rotor blade at 15% span and on the hub platform as well as the stage downstream total pressure and temperature. Both steady and unsteady aspects are addressed. The hub endwall cavity flow has a significant influence on both the time-averaged and time-resolved components of the measured quantities. The effects are shown to be mainly due to an increase of the pitchwise averaged static pressure at hub downstream of the vane when cavity flow ejection is activated.

scholarly journals Unsteady Heat Transfer in Stator-Rotor Interaction by Two Equation Turbulence Model

1998 ◽  
Author(s):  
V. Michelassi ◽  
F. Martelli ◽  
R. Dénos ◽  
T. Arts ◽  
C. H. Sieverding
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Rotor Blade ◽  
Two Dimensions ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Pressure Losses ◽  
Transonic Turbine ◽  
Variable Operating Conditions

A transonic turbine stage is computed by means of an unsteady Navier-Stokes solver. A two equation turbulence model is coupled to a transition model based on integral parameters and an extra transport equation. The transonic stage is modeled in two-dimensions with a variable span height for the rotor row. The analysis of the transonic turbine stage with stator trailing edge coolant ejection is carried out to compute the unsteady pressure and heat transfer distribution on the rotor blade under variable operating conditions. The stator coolant ejection allows the total pressure losses to be reduced although no significant effects on the rotor heat transfer are found in both the computer simulation and measurements. The results compare favorably with experiments both in terms of pressure distribution and heat transfer around the rotor blade.

scholarly journals Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Vikram Shyam ◽  
Ali Ameri ◽  
Jen-Ping Chen
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Rotor Blade ◽  
High Speed ◽  
Pressure Ratio ◽  
Heat Fluxes ◽  
Stagnation Temperature ◽  
Turbine Stage ◽  
Transonic Turbine ◽  
Highly Loaded

In a previous study, vane-rotor shock interactions and heat transfer on the rotor blade of a highly loaded transonic turbine stage were simulated. The geometry consists of a high pressure turbine vane and a downstream rotor blade. This study focuses on the physics of flow and heat transfer in the rotor tip, casing, and hub regions. The simulation was performed using the unsteady Reynolds-averaged Navier–Stokes code MSU-TURBO. A low Reynolds number k-ε model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1% of the blade height. The Reynolds number of the flow is approximately 3×106/m. Unsteadiness was observed at the tip surface that results in intermittent “hot spots.” It is demonstrated that unsteadiness in the tip gap is governed by inviscid effects due to high speed flow and is not strongly dependent on pressure ratio across the tip gap contrary to published observations that have primarily dealt with subsonic tip flows. The high relative Mach numbers in the tip gap lead to a choking of the leakage flow that translates to a relative attenuation of losses at higher loading. The efficacy of new tip geometry is discussed to minimize heat flux at the tip while maintaining choked conditions. In addition, an explanation is provided that shows the mechanism behind the rise in stagnation temperature on the casing to values above the absolute total temperature at the inlet. It is concluded that even in steady (in a computational sense) mode, work transfer to the near tip fluid occurs due to relative shearing by the casing. This is believed to be the first such explanation of the work transfer phenomenon in the open literature. The difference in pattern between steady and time-averaged heat fluxes at the hub is also explained.

Sign in / Sign up

Export Citation Format

Share Document