An Investigation on Turbine Tip and Shroud Heat Transfer

2002 ◽  
Author(s):  
Kam S. Chana ◽  
Terry V. Jones
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Pressure Distributions ◽  
Engine Design ◽  
Nozzle Guide

Detailed experimental investigations have been performed to measure the heat transfer and static pressure distributions on the rotor tip and rotor casing of a gas turbine stage with a shroud-less rotor blade. The turbine stage was a modern high pressure Rolls-Royce aero-engine design with stage pressure ratio of 3.2 and nozzle guide vane (ngv) Reynolds number of 2.54E6. Measurements have been taken with and without inlet temperature distortion to the stage. The measurements were taken in the QinetiQ Isentropic Light Piston Facility and aerodynamic and heat transfer measurements are presented from the rotor tip and casing region. A simple two-dimensional model is presented to estimate the heat transfer rate to the rotor tip and casing region as a function of Reynolds number along the gap.

An Investigation on Turbine Tip and Shroud Heat Transfer

2003 ◽  
Vol 125 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Kam S. Chana ◽  
Terry V. Jones
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Pressure Distributions ◽  
Engine Design ◽  
Nozzle Guide

Detailed experimental investigations have been performed to measure the heat transfer and static pressure distributions on the rotor tip and rotor casing of a gas turbine stage with a shroudless rotor blade. The turbine stage was a modern high pressure Rolls-Royce aero-engine design with stage pressure ratio of 3.2 and nozzle guide vane (ngv) Reynolds number of 2.54E6. Measurements have been taken with and without inlet temperature distortion to the stage. The measurements were taken in the QinetiQ Isentropic Light Piston Facility and aerodynamic and heat transfer measurements are presented from the rotor tip and casing region. A simple two-dimensional model is presented to estimate the heat transfer rate to the rotor tip and casing region as a function of Reynolds number along the gap.

Numerical Prediction of Cooling Performance Sensitivity of 1st Stage Nozzle Guide Vane Under Aerothermal Conditions

2019 ◽  
Author(s):  
Prasert Prapamonthon ◽  
Bo Yin ◽  
Guowei Yang ◽  
Mohan Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
High Pressure ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
High Pressure Turbine ◽  
Cooling Performance ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

Abstract To obtain high power and thermal efficiency, the 1st stage nozzle guide vanes of a high-pressure turbine need to operate under serious circumstances from burned gas coming out of combustors. This leads to vane suffering from effects of high thermal load, high pressure and turbulence, including flow-separated transition. Therefore, it is necessary to improve vane cooling performance under complex flow and heat transfer phenomena caused by the integration of these effects. In fact, these effects on a high-pressure turbine vane are controlled by several factors such as turbine inlet temperature, pressure ratio, turbulence intensity and length scale, vane curvature and surface roughness. Furthermore, if the vane is cooled by film cooling, hole configuration and blowing ratio are important factors too. These factors can change the aerothermal conditions of the vane operation. The present work aims to numerically predict sensitivity of cooling performances of the 1st stage nozzle guide vane under aerodynamic and thermal variations caused by three parameters i.e. pressure ratio, coolant inlet temperature and height of vane surface roughness using Computational Fluid Dynamics (CFD) with Conjugate Heat Transfer (CHT) approach. Numerical results show that the coolant inlet temperature and the vane surface roughness parameters have significant effects on the vane temperature, thereby affecting the vane cooling performances significantly and sensitively.

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.

scholarly journals Aerodynamics and Heat Transfer Investigations on a High Reynolds Number Turbine Cascade

1991 ◽  
Author(s):  
Taher Schobeiri ◽  
Eric McFarland ◽  
Frederick Yeh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
High Reynolds Number ◽  
Test Facility ◽  
Experimental Investigations ◽  
Turbine Cascade ◽  
Calculation Methods ◽  
Transfer Coefficients ◽  
Pressure Distributions ◽  
High Reynolds

In this report the results of aerodynamic and heat transfer experimental investigations performed in a high Reynolds number turbine cascade test facility are analyzed. The experimental facility simulates the high Reynolds number flow conditions similar to those encountered in the space shuttle main engine. In order to determine the influence of Reynolds number on aerodynamic and thermal behavior of the blades, heat transfer coefficients were measured at various Reynolds numbers using liquid crystal temperature measurement technique. Potential flow calculation methods were used to predict the cascade pressure distributions. Boundary layer and heat transfer calculation methods were used with these pressure distributions to verify the experimental results.

Conjugate Heat Transfer Analysis on the Interior Surface of Nozzle Guide Vane with Combined Impingement and Film Cooling

2020 ◽  
Vol 37 (4) ◽  
pp. 327-342
Author(s):  
Arun Kumar Pujari ◽  
B. V. S. S. S Prasad ◽  
Nekkanti Sitaram
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Surface Temperature ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Guide Vane ◽  
Internal Surface ◽  
Conducting Material ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

AbstractThe effect of conjugate heat transfer is investigated on a first stage nozzle guide vane (NGV) of a high pressure gas turbine which has both impingement and film cooling holes. The study is carried out computationally by considering a linear cascade domain, having two passages formed between the vanes, with a chord length of 228 mm and spacing of 200 mm. The effect of (i) coolant and mainstream Reynolds numbers, (ii) thermal conductivity (iii) temperature difference between the mainstream and coolant at the internal surface of the nozzle guide vane are investigated under conjugate thermal condition. The results show that, with increasing coolant Reynolds number the lower conducting material shows larger percentage decrease in surface temperature as compared to the higher conducting material. However, the internal surface temperature is nearly independent of mainstream Reynolds number variation but shows significant variation for higher conducting material. Further, the temperature gradient within the solid thickness of NGV is higher for the lower conductivity material.

An Immersed Mesh Block (IMB) Approach for Conjugate Heat Transfer Predictions

2013 ◽  
Author(s):  
B. Lad ◽  
L. He
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Guide Vane ◽  
Metal Layer ◽  
Turbine Stage ◽  
Physical Processes ◽  
Conduction Heat Transfer ◽  
Nozzle Guide Vane ◽  
Flow Gradients ◽  
Nozzle Guide

Aerothermnal design capability for cooled high pressure turbines depends on resolving complex physical processes such as coolant mixing, coupled fluid-solid convection-conduction heat transfer, and their interactions. This paper presents the development of the generalised Immersed Mesh Block 2 (IMB2) method, which allows high resolution predictions of all these processes to be conducted for a fully cooled turbine stage within a couple of days. The method consists of creating high density meshes of cooling holes to capture the high flow gradients in the fluid domain and separately, generating corresponding meshes for the local metal layer with high temperature gradient. These can then be inserted rapidly into a host turbine domain for conjugate heat transfer as immersed mesh blocks for fluids (IMBf) and metals (IMBm). In this way, conjugate heat transfer meshes of entire rows of cooling holes can be generated and inserted into a host mesh within minutes. The composite domain is then solved with simultaneous coupling between all the fluid and metal IMBs, as well as the host mesh. The paper presents the methodology of this approach and demonstrates its application to a transonic, fully cooled nozzle guide vane.

Effect of Simulated Combustor Temperature Nonuniformity on HP Vane and Endwall Heat Transfer: An Experimental and Computational Investigation

2010 ◽  
Author(s):  
Imran Qureshi ◽  
Arrigo Beretta ◽  
Thomas Povey
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Research Programme ◽  
Test Facility ◽  
Inlet Temperature ◽  
Computational Investigation ◽  
Nozzle Guide Vane ◽  
Inlet Conditions ◽  
Nozzle Guide ◽  
Computational Predictions

This paper presents experimental measurements and computational predictions of surface and endwall heat transfer for a high-pressure (HP) nozzle guide vane (NGV) operating as part of a full HP turbine stage in an annular rotating turbine facility, with and without inlet temperature distortion (hot-streaks). A detailed aerodynamic survey of the vane surface is also presented. The test turbine was the unshrouded MT1 turbine, installed in the Turbine Test Facility (previously called Isentropic Light Piston Facility) at QinetiQ, Farnborough UK. This is a short duration facility, which simulates engine representative M, Re, non-dimensional speed and gas-to-wall temperature ratio at the turbine inlet. The facility has recently been upgraded to incorporate an advanced second-generation combustor simulator, capable of simulating well-defined, aggressive temperature profiles in both the radial and circumferential directions. This work forms part of the pan-European research programme, TATEF II. Measurements of HP vane and endwall heat transfer obtained with inlet temperature distortion are compared with results for uniform inlet conditions. Steady and unsteady CFD predictions have also been conducted on vane and endwall surfaces, using the Rolls-Royce CFD code HYDRA to complement the analysis of experimental results. The heat transfer measurements presented in this paper are the first of their kind in the respect that the temperature distortion is representative of an extreme cycle point measured in the engine situation, and was simulated with good periodicity and with well defined boundary conditions in the test turbine.

Effect of Nozzle Guide Vane Lean Under Influence of Inlet Temperature Traverse

2013 ◽  
Vol 136 (7) ◽  
Author(s):  
A. Rahim ◽  
B. Khanal ◽  
L. He ◽  
E. Romero
Keyword(s):  
Heat Transfer ◽  
Guide Vane ◽  
Tangential Displacement ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Hot Streak ◽  
The Impact

One of the most widely studied parameters in turbine blade shaping is blade lean, i.e., the tangential displacement of spanwise sections. However, there is a lack of published research that investigates the effect of blade lean under nonuniform temperature conditions (commonly referred to as a “hot-streak”) that are present at the combustor exit. Of particular interest is the impact of such an inflow temperature profile on heat transfer when the nozzle guide vane (NGV) blades are shaped. In the present work, a computational study has been carried out for a transonic turbine stage using an efficient unsteady Navier–Stokes solver (HYDRA). The configurations with a nominal vane and a compound leaned vane under uniform and hot-streak inlet conditions are analyzed. After confirming the typical NGV loading and aeroloss redistributions as seen in previous literature on blade lean, the focus has been directed to the rotor aerothermal behavior. While the overall stage efficiencies for the configurations are largely comparable, the results show strikingly different rotor heat transfer characteristics. For a uniform inlet, a leaned NGV has a detrimental effect on the rotor heat transfer. However, once the hot-streak is introduced, the trend is reversed; the leaned NGV leads to favorable heat transfer characteristics in general and for the rotor tip region in particular. The possible causal links for the observed aerothermal features are discussed. The present findings also highlight the significance of evaluating NGV shaping designs under properly conditioned inflow profiles, rather than extrapolating the wisdom derived from uniform inlet cases. The results also underline the importance of including rotor heat transfer and coolability during the NGV design process.

Turbine Tip and Shroud Heat Transfer and Loading—Part A: Parameter Effects Including Reynolds Number, Pressure Ratio, and Gas-to-Metal Temperature Ratio

2003 ◽  
Vol 125 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Marc D. Polanka ◽  
Donald A. Hoying ◽  
Matthew Meininger ◽  
Charles D. MacArthur
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Complex Flow ◽  
Data Set ◽  
Pressure Transducers ◽  
Us Air Force ◽  
Flux Measurements ◽  
Turbine Design

Turbine tip and shroud flow and heat transfer are some of the most complex, yet important, issues in turbine design. Most of the work performed to date has been performed in linear cascades and has investigated such items as the effect of tip geometries and turbulence on tip and shroud pressure and heat transfer. There have been very few full annulus or rotating measurements in the literature. Experimental measurements have been made on a single stage high pressure turbine at the US Air Force Turbine Research Facility (TRF) to aid in the understanding of this phenomena. The TRF is a full scale, rotating rig that operates at matched flow conditions to the true turbine environment. Heat flux measurements were acquired with both Pyrex insert strip and button gages, while the pressure measurements were taken with surface-mounted Kulite® pressure transducers. This paper presents one of the first full rotating, simultaneous pressure and heat transfer measurements to be taken in the turbine tip shroud region. These measurements provide some of the details needed for accurately quantifying the true flow condition in this complex flow regime. Comparisons between the present data and the existing 2-D cascade data were made. This investigation quantified the effects of Reynolds number, inlet temperature, turbine pressure ratio and inlet flow temperature profiles. This provides a benchmark data set for validation of numerical codes.

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.

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