Pre-Swirl Cooling Air Delivery System Performance Study

2012 ◽  
Author(s):  
Roman A. Didenko ◽  
Dmitry V. Karelin ◽  
Dmitry G. Ievlev ◽  
Yuri N. Shmotin ◽  
Georgy P. Nagoga
Keyword(s):  
Delivery System ◽  
System Performance ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Cover Plate ◽  
Performance Study ◽  
Blade Cooling ◽  
Rotating Cavity ◽  
Cooling Air ◽  
Cavity Width

This paper reports the results from numerical simulations of the turbine blade cooling air delivery system performance using commercial CFD code Ansys CFX v11. Computations have been performed with variation of pre-swirl nozzle location radius, rotor-rotor rotating cavity width and the way of air transmission through the cover-plate. There are two ways of air transmission depending on the cover-plate design: through the CAO (circular array of orifices) or CAS (continuous annular slot). Computations are performed within the parameter range similar to gas-turbine engine operating conditions: 0.375<λT<0.98; 0.548<β0<2.5; 1.69·107<Reφ<2.33·107; 2.79·105<Cw<5.73·105. It has been shown that the selection of optimum radius of pre-swirl nozzle location is determined by different factors and depends on design and boundary conditions. The rotor-rotor rotating cavity width does not affect delivery system performances and is selected by a designer based on the constructional necessity, strength, weight and dynamic behavior of the turbine rotor. Rotating orifices reduce the swirl ratio βb before the blade cooling rim slot reduce adiabatic effectiveness Θ and increase loss coefficient ζ.

CFD Analyses of HPT Blade Air Delivery System With and Without Impellers

2011 ◽  
Author(s):  
Charles Wu ◽  
Boris Vaisman ◽  
Kevin McCusker
Keyword(s):  
Delivery System ◽  
Pressure Loss ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Manufacturing Cost ◽  
Cfd Analysis ◽  
Swirl Ratio ◽  
Blade Cooling ◽  
Supply Pressure ◽  
Cooling Air

In the design of a HPT blade cooling air delivery system, sufficient supply pressure is required to guarantee HPT blades are working properly in the high temperature environment. A design goal is to set a pressure level at the blade inlet that will prevent the ingestion of gaspath air into the blades which is caused by pressure fluctuations under various operating conditions and other uncertainties. Traditional 1-D design tools are not sophisticated enough for detailed system analysis. Therefore, CFD (Computational Fluid Dynamics) analysis was utilized for designing HPT blade cooling air delivery system to guarantee meeting the supply pressure requirement. Two HPT blade air delivery systems were explored. The baseline is a cooling air delivery system without radial impellers. It provides a simplistic design at low manufacturing cost, however CFD analysis shows that the system has a larger pressure loss at the broach slot entrance and delivers low supply pressure. The alternative is a cooling air delivery system with radial impellers. CFD analysis shows that the system with impellers results in much better aerodynamic performance at the broach slots and provides high supply pressure, but comes with the price of high manufacturing cost and lower TSFC due to the parasitic drag induced by impellers. For the alternative approach, three high solidity impeller designs were analyzed. The alternative approaches analyzed had inlet angles of 0°, 30°, 90° and exit angles of 0°, respectively. Comparisons of detailed aerodynamic performance are presented in the paper. CFD simulation reveals that the source of pressure loss without impellers is caused by mismatch of the swirl ratio at broach slot entrance. CFD results show that a system with radial impellers produces a better matched swirl ratio at broach slot entrance. Radial impellers enhance aerodynamic performance and improve pressure distribution within broach slots.

Flow in a “Cover-Plate” Pre-Swirl Rotor-Stator System

1997 ◽  
Author(s):  
Hasan Karabay ◽  
Jian-Xin Chen ◽  
Robert Pilbrow ◽  
Michael Wilson ◽  
J. Michael Owen
Keyword(s):  
Experimental Study ◽  
Vortex Flow ◽  
Reynolds Numbers ◽  
Tangential Component ◽  
Cover Plate ◽  
Rotating Disc ◽  
Blade Cooling ◽  
Rotating Cavity ◽  
Cooling Air ◽  
Nondimensional Temperature

This paper describes a combined theoretical, computational and experimental study of the flow in an adiabatic pre-swirl rotor-stator system. Pre-swirl cooling air, supplied through nozzles in the stator, flows radially outward, in the rotating cavity between the rotating disc and a cover-plate attached to it, leaving the system through blade-cooling holes in the disc. An axisymmetric elliptic solver, incorporating the Launder-Sharma low-Reynolds-number k-ε turbulence model, is used to compute the flow. An LDA system is used to measure the tangential component of velocity, Vϕ, in the rotating cavity of a purpose-built rotating-disc rig. For rotational Reynolds numbers up to 1.2 × 106 and pre-swirl ratios up to 2.5, agreement between the computed and measured values of Vϕ is mainly very good, and the results confirm that free-vortex flow occurs throughout most of the rotating cavity. Computed values of the pre-swirl effectiveness (or the nondimensional temperature difference between the pre-swirl and blade-cooling air) agree closely with theoretical values obtained from a thermodynamic analysis of an adiabatic system.

Flow in a “Cover-Plate” Preswirl Rotor–Stator System

1999 ◽  
Vol 121 (1) ◽  
pp. 160-166 ◽  
Author(s):  
H. Karabay ◽  
J.-X. Chen ◽  
R. Pilbrow ◽  
M. Wilson ◽  
J. M. Owen
Keyword(s):  
Vortex Flow ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Tangential Component ◽  
Cover Plate ◽  
Rotating Disc ◽  
Blade Cooling ◽  
Rotating Cavity ◽  
Cooling Air ◽  
Nondimensional Temperature

This paper describes a combined theoretical, computational, and experimental study of the flow in an adiabatic preswirl rotor–stator system. Preswirl cooling air, supplied through nozzles in the stator, flows radially outward, in the rotating cavity between the rotating disk and a cover-plate attached to it, leaving the system through blade-cooling holes in the disk. An axisymmetric elliptic solver, incorporating the Launder–Sharma low-Reynolds-number k–ε turbulence model, is used to compute the flow. An LDA system is used to measure the tangential component of velocity, Vφ, in the rotating cavity of a purpose-built rotating-disc rig. For rotational Reynolds numbers up to 1.2 × 106 and preswirl ratios up to 2.5, agreement between the computed and measured values of Vφ is mainly very good, and the results confirm that free-vortex flow occurs in most of the rotating cavity. Computed values of the preswirl effectiveness (or the nondimensional temperature difference between the preswirl and blade-cooling air) agree closely with theoretical values obtained from a thermodynamic analysis of an adiabatic system.

Performance Study of a 1 MW Gas Turbine Using Variable Geometry Compressor and Turbine Blade Cooling

2010 ◽  
Author(s):  
Cleverson Bringhenti ◽  
Jesuino Takachi Tomita ◽  
Joa˜o Roberto Barbosa
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Turbine Blades ◽  
Axial Flow ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Variable Geometry ◽  
Performance Study ◽  
Turbine Blade Cooling ◽  
Blade Cooling

This work presents the performance study of a 1 MW gas turbine including the effects of blade cooling and compressor variable geometry. The axial flow compressor, with Variable Inlet Guide Vane (VIGV), was designed for this application and its performance maps synthesized using own high technological contents computer programs. The performance study was performed using a specially developed computer program, which is able to numerically simulate gas turbine engines performance with high confidence, in all possible operating conditions. The effects of turbine blades cooling were calculated for different turbine inlet temperatures (TIT) and the influence of the amount of compressor-bled cooling air was studied, aiming at efficiency maximization, for a specified blade life and cooling technology. Details of compressor maps generation, cycle analysis and blade cooling are discussed.

Heat Transfer in a “Cover-Plate” Preswirl Rotating-Disk System

1999 ◽  
Vol 121 (2) ◽  
pp. 249-256 ◽  
Author(s):  
R. Pilbrow ◽  
H. Karabay ◽  
M. Wilson ◽  
J. M. Owen
Keyword(s):  
Heat Transfer ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Turbine Disk ◽  
Cover Plate ◽  
Blade Cooling ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Cooling Air ◽  
Plate System

In most gas turbines, blade-cooling air is supplied from stationary preswirl nozzles that swirl the air in the direction of rotation of the turbine disk. In the “cover-plate” system, the preswirl nozzles are located radially inward of the blade-cooling holes in the disk, and the swirling airflows radially outward in the cavity between the disk and a cover-plate attached to it. In this combined computational and experimental paper, an axisymmetric elliptic solver, incorporating the Launder–Sharma and the Morse low-Reynolds-number k–ε turbulence models, is used to compute the flow and heat transfer. The computed Nusselt numbers for the heated “turbine disk” are compared with measured values obtained from a rotating-disk rig. Comparisons are presented, for a wide range of coolant flow rates, for rotational Reynolds numbers in the range 0.5 X 106 to 1.5 X 106, and for 0.9 < βp < 3.1, where βp is the preswirl ratio (or ratio of the tangential component of velocity of the cooling air at inlet to the system to that of the disk). Agreement between the computed and measured Nusselt numbers is reasonably good, particularly at the larger Reynolds numbers. A simplified numerical simulation is also conducted to show the effect of the swirl ratio and the other flow parameters on the flow and heat transfer in the cover-plate system.

Heat Transfer in a “Cover-Plate” Pre-Swirl Rotating-Disc System

1998 ◽  
Author(s):  
Robert Pilbrow ◽  
Hasan Karabay ◽  
Michael Wilson ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Cover Plate ◽  
Swirl Ratio ◽  
Rotating Disc ◽  
Blade Cooling ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Turbine Disc ◽  
Cooling Air

In most gas turbines, blade-cooling air is supplied from stationary pre-swirl nozzles that swirl the air in the direction of rotation of the turbine disc. In the “cover-plate” system, the pre-swirl nozzles are located radially inward of the blade-cooling holes in the disc, and the swirling air flows radially outwards in the cavity between the disc and a cover-plate attached to it. In this combined computational and experimental paper, an axisymmetric elliptic solver, incorporating the Launder-Sharma and the Morse low-Reynolds-number k-ε turbulence models, is used to compute the flow and heat transfer. The computed Nusselt numbers for the heated “turbine disc” are compared with measured values obtained from a rotating-disc rig. Comparisons are presented, for a wide range of coolant flow rates, for rotational Reynolds numbers in the range 0.5 × 106 to 1.5 × 106, and for 0.9 < βp < 3.1, where βp is the pre-swirl ratio (or ratio of the tangential component of velocity of the cooling air at inlet to the system to that of the disc). Agreement between the computed and measured Nusselt numbers is reasonably good, particularly at the larger Reynolds numbers. A simplified numerical simulation is also conducted to show the effect of the swirl ratio and the other flow parameters on the flow and heat transfer in the cover-plate system.

scholarly journals Performance of Pre-Swirl Rotating-Disc Systems

1999 ◽  
Author(s):  
Hasan Karabay ◽  
Robert Pilbrow ◽  
Michael Wilson ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Turbulence Models ◽  
Cover Plate ◽  
Swirl Ratio ◽  
Rotating Disc ◽  
Blade Cooling ◽  
Cooling Air

This paper summarises and extends recent theoretical, computational and experimental research into the fluid mechanics, thermodynamics and heat transfer characteristics of the so-called cover-plate pre-swirl system. Experiments were carried out in a purpose-built rotating-disc rig, and the Reynolds-averaged Navier-Stokes equations were solved using 2D (axisymmetric) and 3D computational codes, both of which incorporated low-Reynolds-number k-ε turbulence models. The free-vortex flow, which occurs inside the rotating cavity between the disc and cover-plate, is controlled principally by the pre-swirl ratio, βp: this is the ratio of the tangential velocity of the air leaving the nozzles to that of the rotating disc. Computed values of the tangential velocity are in good agreement with measurements, and computed distributions of pressure are in close agreement with those predicted by a one-dimensional theoretical model. It is shown theoretically and computationally that there is a critical pre-swirl ratio, βp,crit, for which the frictional moment on the rotating discs is zero, and there is an optimal pre-swirl ratio, βp,opt, where the average Nusselt number is a minimum. Computations show that, for βp < βp,opt, the temperature of the blade-cooling air decreases as βp increases; for βp > βp,opt, whether the temperature of the cooling air increases or decreases as βp increases depends on the flow conditions and on the temperature difference between the disc and the air. Owing to the three-dimensional flow and heat transfer near the blade-cooling holes, and to unquantifiable uncertainties in the experimental measurements, there were significant differences between the computed and measured temperatures of the blade-cooling air. In the main, the 3D computations produced smaller differences than the 2D computations.

CFD Investigation of Vane Nozzle and Impeller Design for HPT Blade Cooling Air Delivery System

2013 ◽  
Author(s):  
Shuqing Tian ◽  
Qin Zhang ◽  
Hui Liu
Keyword(s):  
Delivery System ◽  
Pressure Loss ◽  
Aerodynamic Performance ◽  
Blade Cooling ◽  
System Pressure ◽  
Total Temperature ◽  
Swirl Vane ◽  
Radial Outflow ◽  
Cooling Air ◽  
Main Factor

In the design of a HPT blade cooling air delivery system, sufficient supply pressure and lower relative total temperature are required to guarantee HPT blades working properly in the high temperature environment. The pre-swirl vane nozzles and the radial impellers are used in the delivery system with lower radial location of pre-swirl nozzle to achieve the requirements. In this paper, CFD analysis is utilized for designing the vane nozzles and the radial impellers. Two HPT blade cooling air delivery systems were explored. The baseline is a system without impellers, and the alternative is a system with impellers. The results show that the impeller contributes to the delivery system by pumping effectiveness thus decreasing the extracted air pressure. The parity of swirl ratio between the flow and the broach slots is a main factor that decreases the system pressure loss, which can be improved by the radial impellers. The well-designed contoured radial-impeller vane with 30° front angle and 20° trailing angle is recommended in the blade cooling air delivery system design because of its good aerodynamic performance and closely radial outflow. The cascade vane nozzle with more than 70° angle turn is recommended in the pre-swirl nozzle design. It has a good aerodynamic performance with discharge coefficient greater than 0.99 and deviation angle less than 1.3°. The well-designed radial impeller pays big contributions to the blade cooling air delivery system with 11.4% increase of the thermal effectiveness and 10.2% decrease of the pressure loss versus the system without impellers.

Measurement of Pressures and Temperatures in a Cover-Plate Pre-Swirl System

2018 ◽  
Author(s):  
Heng Wu ◽  
Gaowen Liu ◽  
Zhipeng Wu ◽  
Qing Feng ◽  
Wang Yangang
Keyword(s):  
Discharge Coefficient ◽  
Turbine Blades ◽  
Temperature Drop ◽  
Cover Plate ◽  
Test Rig ◽  
Pressure Transducers ◽  
Blade Cooling ◽  
Nozzle Pressure ◽  
Total Temperature ◽  
Cooling Air

A Pre-swirl system is used to supply cooling air to the rotating turbine blades where the pressure and temperature of the supplied air is crucial for blade cooling. A test rig was designed to simulate the flow in a cover-plate Pre-swirl system. Some important performance parameters of a pre-swirl system were measured at different mass flow rate (Cw is up to 1.35 × 105), rotation speed (Maϕ is up to 0.744) and outlet pressure (210 kPa and 310 kPa). These parameters include discharge coefficient of pre-swirl nozzle, pressure ratios, temperature drop and rotor work consumption. To get rotor pressure boost ratio and temperature drop, pressures and temperatures on the rotating turbine disc were measured respectively by tiny pressure transducers and thermo-couples co-rotating with the axis and recorded by a customized data recorder co-rotating also. By measuring the inlet and outlet total temperature of the test rig, work consumption was estimated approximately with heat transfer ignored.

Performance of Pre-Swirl Rotating-Disc Systems

2000 ◽  
Vol 122 (3) ◽  
pp. 442-450 ◽  
Author(s):  
Hasan Karabay ◽  
Robert Pilbrow ◽  
Michael Wilson ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Tangential Velocity ◽  
Cover Plate ◽  
Two Dimensional ◽  
Swirl Ratio ◽  
Rotating Disc ◽  
Blade Cooling ◽  
Cooling Air

This paper summarizes and extends recent theoretical, computational, and experimental research into the fluid mechanics, thermodynamics, and heat transfer characteristics of the so-called cover-plate pre-swirl system. Experiments were carried out in a purpose-built rotating-disc rig, and the Reynolds-averaged Navier-Stokes equations were solved using two-dimensional (axisymmetric) and three-dimensional computational codes, both of which incorporated low-Reynolds-number k-ε turbulence models. The free-vortex flow, which occurs inside the rotating cavity between the disc and cover-plate, is controlled principally by the pre-swirl ratio, βp: this is the ratio of the tangential velocity of the air leaving the nozzles to that of the rotating disc. Computed values of the tangential velocity are in good agreement with measurements, and computed distributions of pressure are in close agreement with those predicted by a one-dimensional theoretical model. It is shown theoretically and computationally that there is a critical pre-swirl ratio, βp,crit, for which the frictional moment on the rotating discs is zero, and there is an optimal pre-swirl ratio, βp,opt, where the average Nusselt number is a minimum. Computations show that, for βp<βp,opt, the temperature of the blade-cooling air decreases as βp increases; for βp>βp,opt, whether the temperature of the cooling air increases or decreases as βp increases depends on the flow conditions and on the temperature difference between the disc and the air. Owing to the three-dimensional flow and heat transfer near the blade-cooling holes, and to unquantifiable uncertainties in the experimental measurements, there were significant differences between the computed and measured temperatures of the blade-cooling air. In the main, the three-dimensional computations produced smaller differences than the two-dimensional computations. [S0742-4795(00)01902-5]

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