Mainstream Ingress Suppression in Gas Turbine Disk Cavities

1994 ◽  
Vol 116 (2) ◽  
pp. 339-346 ◽  
Author(s):  
V. I. Khilnani ◽  
L. C. Tsai ◽  
S. H. Bhavnani ◽  
J. M. Khodadadi ◽  
J. S. Goodling ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Laser Sheet ◽  
Reynolds Numbers ◽  
Labyrinth Seal ◽  
Turbine Disk ◽  
Scale Model ◽  
Design Data ◽  
Outer Periphery ◽  
Visualization Experiments ◽  
Good Agreement

The sealing characteristics of an air-cooled gas turbine disk cavity have been studied using laser sheet flow visualization. Experiments were performed on a simplified half-scale model of an actual gas turbine disk cavity. This type of rotor–stator geometry with a double-toothed-rim (DTR) seal at the outer periphery and a labyrinth seal at the inner periphery of the cavity has been tested for its ability in preventing ingress of hot mainstream gases. The results show good agreement with previously esimated design data. Experiments were conducted for various labyrinth seal flow rates and rotational Reynolds numbers up to 1.52 × 106. The effects of rotor eccentricity on minimum purge flows have also been discussed.

Effective Sealing of a Disk Cavity Using a Double-Toothed Rim Seal

1992 ◽  
Author(s):  
S. H. Bhavnani ◽  
V. I. Khilnani ◽  
L.-C. Tsai ◽  
J. M. Khodadadi ◽  
J. S. Goodling ◽  
...  
Keyword(s):  
Laser Sheet ◽  
Reynolds Numbers ◽  
Labyrinth Seal ◽  
Superior Performance ◽  
Scale Model ◽  
Pressure Measurements ◽  
Design Data ◽  
Outer Periphery ◽  
Turbo Expander ◽  
Cavity Configuration

The trend towards higher gas turbine inlet temperatures is a natural consequence of the pursuit of higher turbine operating efficiencies. More efficient disk cooling technology is therefore a prime need. The sealing characteristics of a advanced air-cooled turbo-expander disk cavity have been studied using laser sheet flow visualization and static pressure measurements. Experiments were performed on a simplified half-scale model of an actual low pressure turbo-expander first-stage disk cavity. The rotor-stator geometry tested was equipped with a double-toothed rim (DTR) seal at the outer periphery and a labyrinth seal (or shaft seal) at the inner periphery of the cavity. This is one of the first studies that incorporates the effects of shaft sealing flows. Experiments were conducted in the absence of an external flow stream for various labyrinth seal flow rates, and rotational Reynolds numbers up to 1.52 × 106. The results confirm the adequacy of previously estimated design data for this disk cavity configuration. Pressure measurements reveal that a pressure difference criterion based on the differential pressure across the teeth of the rim seal can be used to detect ingress of mainstream flow. The superior performance of the seal geometry studied was confirmed by a comparison against a single-toothed rim seal and a simple axial rim seal.

An Experimental Study of Fluid Flow in Disk Cavities

1992 ◽  
Vol 114 (2) ◽  
pp. 454-461 ◽  
Author(s):  
S. H. Bhavnani ◽  
J. M. Khodadadi ◽  
J. S. Goodling ◽  
J. Waggott
Keyword(s):  
Experimental Study ◽  
Fluid Flow ◽  
Gas Turbine ◽  
Experimental Studies ◽  
Reynolds Numbers ◽  
Turbine Disk ◽  
Published Data ◽  
Disk System ◽  
Flow Rates ◽  
Pressure Distributions

Results are presented for an experimental study of fluid flow in models of gas turbine disk cavities. Experiments were performed on 70-cm-dia disks for rotational Reynolds numbers up to 2.29 × 106. Velocity and pressure distributions are presented and compared to previous theoretical and experimental studies for a free disk, and an unshrouded plane Rotor–Stator disk system. Minimum coolant flow rates for the prevention of ingress, determined for the case of a simple axial rim seal, compare well with previously published data.

Effect of Pin Fins on Jet Impingement Heat Transfer on A Rotating Disk

2021 ◽  
Author(s):  
Pratik S. Bhansali ◽  
Kishore Ranganath Ramakrishnan ◽  
Srinath Ekkad
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Disk Surface ◽  
Reynolds Numbers ◽  
Turbine Disk ◽  
Large Space ◽  
Air Jet ◽  
Pin Fins

Abstract Heat transfer on rotating surfaces is a predominant phenomenon in rotating machinery as in the case of the gas turbine disk. The gas turbine disk needs to be cooled as well as protected from the ingress of hot turbine gases in the stator-rotor cavity. In the current study, an experimental investigation of the heat transfer of an impinging air jet on a surface rotating at low rotational Reynolds number has been carried out. Addition of pin-fins on the disk surface is an effective way to enhance the heat transfer between the disk and the jet of cooling air. The effect of addition of an inline array of square pin fins on the rotating disk heat transfer has been investigated in this study. Steady state measurements have been carried out using thermocouples embedded at different locations in an aluminum disk with an array of square pin-fins rotating in a large space. Experiments have been conducted at rotational Reynolds numbers (ReR) of 5,487–12,803 based on the disk diameter (D) and jet Reynolds numbers (Re) of 5,000–18,000 based on the jet diameter (d). Two different ratios of jet to nozzle spacing and jet diameter (z/d) of 2 and 4 and three different impingement locations – at eccentricities (ε) – 0, 0.33 and 0.67 have been considered. The diameter of the impinging jet has been kept constant in order to maintain an equal jet footprint across all the cases. The area averaged Nusselt number over the surface with pin fins has been compared with a smooth rotating disk of equal diameter. Results indicate that for the smooth surface, ε and ReR have negligible effect on Nu. However, addition of pin fins enhance Nu by a factor between 1.5 and 3.9 in the present study. Qualitative visualization of flow field has been performed using the commercial simulation package Ansys Fluent to further understand the heat transfer trends.

An Experimental Study of Fluid Flow in Disk Cavities

1991 ◽  
Author(s):  
S. H. Bhavnani ◽  
J. M. Khodadadi ◽  
J. S. Goodling ◽  
J. Waggott
Keyword(s):  
Experimental Study ◽  
Fluid Flow ◽  
Gas Turbine ◽  
Experimental Studies ◽  
Reynolds Numbers ◽  
Turbine Disk ◽  
Published Data ◽  
Disk System ◽  
Flow Rates ◽  
Pressure Distributions

Results are presented for an experimental study of fluid flow in models of gas turbine disk cavities. Experiments were performed on 70 cm diameter disks for rotational Reynolds numbers up to 2.29 × 106. Velocity and pressure distributions are presented and compared to previous theoretical and experimental studies for a free disk, and an unshrouded and shrouded plane rotor-stator disk system. Minimum coolant flow rates for the prevention of ingress, determined for the case of a simple axial rim seal, compare well with previously published data.

Simulation of Unsteady Flow Around a Cylinder

2015 ◽  
Vol 3 (2) ◽  
pp. 28-49
Author(s):  
Ridha Alwan Ahmed
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Mean Value ◽  
Navier Stokes ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Flow Around A Cylinder ◽  
Numerical Grid ◽  
Good Agreement

       In this paper, the phenomena of vortex shedding from the circular cylinder surface has been studied at several Reynolds Numbers (40≤Re≤ 300).The 2D, unsteady, incompressible, Laminar flow, continuity and Navier Stokes equations have been solved numerically by using CFD Package FLUENT. In this package PISO algorithm is used in the pressure-velocity coupling.        The numerical grid is generated by using Gambit program. The velocity and pressure fields are obtained upstream and downstream of the cylinder at each time and it is also calculated the mean value of drag coefficient and value of lift coefficient .The results showed that the flow is strongly unsteady and unsymmetrical at Re>60. The results have been compared with the available experiments and a good agreement has been found between them

scholarly journals Fully Coupled Large Eddy Simulation of Conjugate Heat Transfer in a Ribbed Channel with a 0.1 Blockage Ratio

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2096
Author(s):  
Joon Ahn ◽  
Jeong Chul Song ◽  
Joon Sik Lee
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Scale Model ◽  
Computational Domain ◽  
Blockage Ratio ◽  
Ribbed Channel ◽  
Large Eddy ◽  
Cooling Passage

Large eddy simulations are performed to analyze the conjugate heat transfer of turbulent flow in a ribbed channel with a heat-conducting solid wall. An immersed boundary method (IBM) is used to determine the effect of heat transfer in the solid region on that in the fluid region in a unitary computational domain. To satisfy the continuity of the heat flux at the solid–fluid interface, effective conductivity is introduced. By applying the IBM, it is possible to fully couple the convection on the fluid side and the conduction inside the solid and use a dynamic subgrid scale model in a Cartesian grid. The blockage ratio (e/H) is set at 0.1, which is typical for gas turbine blades. Through conjugate heat transfer analysis, it is confirmed that the heat transfer peak in front of the rib occurs because of the impinging of the reattached flow and not the influence of the thermal boundary condition. When the rib turbulator acts as a fin, its efficiency and effectiveness are predicted to be 98.9% and 8.32, respectively. When considering conjugate heat transfer, the total heat transfer rate is reduced by 3% compared with that of the isothermal wall. The typical Biot number at the internal cooling passage of a gas turbine is <0.1, and the use of the rib height as the characteristic length better represents the heat transfer of the rib.

Heat Transfer in a Surfactant Drag-Reducing Solution—A Comparison With Predictions for Laminar Flow

2005 ◽  
Vol 128 (6) ◽  
pp. 557-563 ◽  
Author(s):  
Paul L. Sears ◽  
Libing Yang
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Reynolds Numbers ◽  
High Heat ◽  
High Heat Flux ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Drag Reducing Additive ◽  
Good Agreement

Heat transfer coefficients were measured for a solution of surfactant drag-reducing additive in the entrance region of a uniformly heated horizontal cylindrical pipe with Reynolds numbers from 25,000 to 140,000 and temperatures from 30to70°C. In the absence of circumferential buoyancy effects, the measured Nusselt numbers were found to be in good agreement with theoretical results for laminar flow. Buoyancy effects, manifested as substantially higher Nusselt numbers, were seen in experiments carried out at high heat flux.

Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

2009 ◽  
Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Axial Flow ◽  
Experimental Results ◽  
Scale Model ◽  
Data Set ◽  
Pressure Profiles ◽  
Scale Models ◽  
Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

The Civic: A Concept in Vortex Induced Combustion for the Solar Gemini 10 kW Gas Turbine

1981 ◽  
Vol 103 (1) ◽  
pp. 34-42 ◽  
Author(s):  
J. R. Shekleton
Keyword(s):  
Gas Turbine ◽  
Diffusion Flames ◽  
Reynolds Numbers ◽  
Flame Stabilization ◽  
Fuel Injector ◽  
Combustion Chambers ◽  
Turbine Generator ◽  
Fuel Injectors ◽  
Swirl Flame ◽  
Combustion Processes

The Radial Engine Division of Solar Turbines International, an Operating Group of International Harvester, under contract to the U.S. Army Mobility Equipment Research & Development Command, developed and qualified a 10 kW gas turbine generator set. The very small size of the gas turbine created problems and, in the combustor, novel solutions were necessary. Differing types of fuel injectors, combustion chambers, and flame stabilizing methods were investigated. The arrangement chosen had a rotating cup fuel injector, in a can combustor, with conventional swirl flame stabilization but was devoid of the usual jet stirred recirculation. The use of centrifugal force to control combustion conferred substantial benefit (Rayleigh Instability Criteria). Three types of combustion processes were identified: stratified and unstratified charge (diffusion flames) and pre-mix. Emphasis is placed on five nondimensional groups (Richardson, Bagnold, Damko¨hler, Mach, and Reynolds numbers) for the better control of these combustion processes.

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