Prediction of Ingestion Through Turbine Rim Seals—Part 2: Externally-Induced and Combined Ingress

2009 ◽  
Author(s):  
J. Michael Owen
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Gas Turbines ◽  
Swirling Flow ◽  
Published Data ◽  
Flow Rates ◽  
Hot Gas ◽  
Predicted Values ◽  
Good Agreement

Ingress of hot gas through the rim seals of gas turbines can be modelled theoretically using the so-called orifice equations. In Part 1 (ASME GT 2009-59121) of this two-part paper, the orifice equations were derived for compressible and incompressible swirling flow, and the incompressible equations were solved for axisymmetric rotationally-induced (RI) ingress. In Part 2, the incompressible equations are solved for non-axisymmetric externally-induced (EI) ingress and for combined EI and RI ingress. The solutions show how the nondimensional ingress and egress flow rates vary with Θ0, the ratio of the flow rate of sealing air to the flow rate necessary to prevent ingress. For EI ingress, a ‘saw-tooth model’ is used for the circumferential variation of pressure in the external annulus, and it is shown that ε, the sealing effectiveness, depends principally on Θ0; the theoretical variation of ε with Θ0 is similar to that found in Part 1 for RI ingress. For combined ingress, the solution of the orifice equations shows the transition from RI to EI ingress as the amplitude of the circumferential variation of pressure increases. The predicted values of ε for EI ingress are in good agreement with available experimental data, but there are insufficient published data to validate the theory for combined ingress.

Prediction of Ingestion Through Turbine Rim Seals—Part II: Externally Induced and Combined Ingress

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
J. Michael Owen
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Gas Turbines ◽  
Swirling Flows ◽  
Published Data ◽  
Flow Rates ◽  
Hot Gas ◽  
Predicted Values ◽  
Good Agreement

Ingress of hot gas through the rim seals of gas turbines can be modeled theoretically using the so-called orifice equations. In Part I of this two-part paper, the orifice equations were derived for compressible and incompressible swirling flows, and the incompressible equations were solved for axisymmetric rotationally induced (RI) ingress. In Part II, the incompressible equations are solved for nonaxisymmetric externally induced (EI) ingress and for combined EI and RI ingress. The solutions show how the nondimensional ingress and egress flow rates vary with Θ0, the ratio of the flow rate of sealing air to the flow rate necessary to prevent ingress. For EI ingress, a “saw-tooth model” is used for the circumferential variation of pressure in the external annulus, and it is shown that ε, the sealing effectiveness, depends principally on Θ0; the theoretical variation of ε with Θ0 is similar to that found in Part I for RI ingress. For combined ingress, the solution of the orifice equations shows the transition from RI to EI ingress as the amplitude of the circumferential variation of pressure increases. The predicted values of ε for EI ingress are in good agreement with the available experimental data, but there are insufficient published data to validate the theory for combined ingress.

Prediction of Ingestion Through Turbine Rim Seals—Part 1: Rotationally-Induced Ingress

2009 ◽  
Author(s):  
J. Michael Owen
Keyword(s):  
Flow Rate ◽  
Swirling Flow ◽  
Turbine Blades ◽  
External Pressure ◽  
Radial Gradient ◽  
Mainstream Flow ◽  
Predicted Values ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
Good Agreement

The mainstream flow past the stationary nozzle guide vanes and rotating turbine blades in a gas turbine creates an unsteady non-axisymmetric variation of pressure in the annulus radially outward of the rim seal. Ingress and egress occur through those parts of the seal clearance where the external pressure is higher and lower, respectively, than that in the wheel-space; this non-axisymmetric type of ingestion is referred to here as externally-induced (EI) ingress. Another cause of ingress is that the rotating air inside the wheel-space creates a radial gradient of pressure so that the pressure inside the wheel-space can be less than that outside; this creates rotationally-induced (RI) ingress, which — unlike EI ingress — can occur even if the flow in the annulus is axisymmetric. Although EI ingress is usually dominant in a turbine, there are conditions under which both EI and RI ingress are significant: these cases are referred to as combined ingress. In Part 1 of this two-part paper, the so-called orifice equations are derived for compressible and incompressible swirling flow, and the incompressible equations are solved analytically for RI ingress. The resulting algebraic expressions show how the nondimensional ingress and egress vary with Θ0, the ratio of the flow rate of sealing air to the flow rate necessary to prevent ingress. It is shown that ε, the sealing effectiveness, depends principally on Θ0, and the predicted values of ε are in mainly good agreement with available experimental data. Part 2 (ASME GT2009-59122) concentrates on the solution and validation of the orifice equations for EI and combined ingress.

Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 5 — Fluid Dynamics of Wheel-Space

2013 ◽  
Author(s):  
Carl M. Sangan ◽  
Yogesh Lalwani ◽  
J. Michael Owen ◽  
Gary D. Lock
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Outer Region ◽  
Turbine Stage ◽  
Rotating Disc ◽  
Flow Rates ◽  
Hot Gas ◽  
Fluid Core ◽  
Swirl Velocity ◽  
Good Agreement

This paper discusses the flow structure in typical rotor-stator systems with ingress and egress. Measurements of concentration, velocity and pressure were made using a rotating-disc rig which experimentally simulated hot gas ingestion into the wheel-space of an axial turbine stage. Externally-induced ingress through rim seals was generated from the non-axisymmetric pressures produced by the flow over the vanes and blades in the external annulus. Measurements were conducted using several single- and double-seal geometries and for a range of sealing flow rates and rotational speeds. The concentration measurements showed that the amount of ingress, which increased with decreasing sealing flow rate, depended on the seal geometry. The swirl velocity in the fluid core increased with decreasing sealing-flow rate but, outside the outer region in the wheel-space, it was largely unaffected by the seal geometry or by the amount of ingress. The radial distribution of static pressure, calculated from the measured swirl velocity in the core, was in good agreement with the pressures measured on the stator. The data for the double seals demonstrated that the ingested gas was predominately confined to the region between the seals near the periphery of the wheel-space; in the inner wheel-space, the effectiveness is shown to be significantly higher.

Numerical Investigation of the Nonreacting Swirling Flow Structure Downstream of Industrial Gas Turbine Burner With the Central Body

2015 ◽  
Author(s):  
Ivan A. Zubrilin ◽  
Dmitriy N. Dmitriev ◽  
Sergey S. Matveev ◽  
Sergey G. Matveev
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Flow Structure ◽  
Flow Rate ◽  
Central Body ◽  
Swirling Flow ◽  
Air Flow ◽  
Air Flow Rate ◽  
Piv Measurements ◽  
Good Agreement

This paper will discuss the investigation of the nonreacting swirling flow downstream of the burner with the central body. This burner is designed for burning partially prepared fuel-air mixture. The burner consists of the axial swirler and the central body. The swirler plays the role of the premixer, and the central body is used to stabilize the flame. The simulation was conducted with the commercial software ANSYS Fluent 15.0. At present, the most widespread CFD approaches to the swirling flow investigation are URANS and LES. In this study URANS is used for obtaining flow charts and LES is used for detailed research of swirling flow structures. The influences of the model parameters (turbulence models, geometry simplification) and numerical parameters (the number of grid elements) on the burner pressure drop are shown in the simulation results. The LES results were compared with the experimental data on the flow structure downstream of the burner. The measurements were provided by 2D PIV with the imaging frequency of 500 Hz and 1000 Hz. It was found that in the investigated range of parameters the burner pressure drop changes slightly and is in good agreement with the experimental data. It was shown that the results of the PIV measurements with the different imaging frequency are in good agreement. The results show that flow behavior achieved in simulation is in accordance with the PIV measurements. It is shown that the flow separation from the central body trailing edge results in formation of large eddies and high velocity fluctuations. On the one hand it can contribute to the mixing of pilot fuel with air, but on the other hand it can lead to high amplitude pressure oscillations during combustion. The form and the frequency of the precessing vortex core were discovered. It was found that the maximum air flow rate through the recirculation zone is about 12% of the total air flow rate through the burner.

Investigation of Quench-16 Experiment With MELCOR Computer Code

2014 ◽  
Author(s):  
Petya Vryashkova ◽  
Pavlin Groudev ◽  
Antoaneta Stefanova
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Initial Temperature ◽  
Computer Code ◽  
Air Flow Rate ◽  
Fuel Rod ◽  
Fuel Bundle ◽  
Oxygen Starvation ◽  
Air Ingress ◽  
Good Agreement

This paper presents a comparison of MELCOR calculated results with experimental data for the QUENCH-16 experiment. The analysis for the air ingress experiment QUENCH-16 has been performed by INRNE. The calculations have been performed with MELCOR code. The QUENCH-16 experiment has been performed on 27-th of July 2011 in the frame of the EC-supported LACOMECO program. The experiments have focused on air ingress investigation into an overheated core following earlier partial oxidation in steam. QUENCH-16 has been performed with limited pre-oxidation and low air flow rate. One of the main objectives of QUENCH-16 was to examine the interaction between nitrogen and oxidized cladding during a prolonged period of oxygen starvation. The bundle is made from 20 heated fuel rod simulators arranged in two concentric rings and one unheated central fuel rod simulator, each about 2.5 m long. The tungsten heaters were surrounded by annular ZrO2 pellets to simulate the UO2 fuel. The geometry and most other bundle components are prototypical for Western-type PWRs. To improve the obtained results it has been made a series of calculations to select an appropriate initial temperature of the oxidation of the fuel bundle and modified correlation oxidation of Zircaloy with MELCOR computer code. The compared results have shown good agreement of calculated hydrogen and oxygen starvation in comparison with test data.

Effect of Outer Fin Axial Gap on the Sealing Effectiveness and Fluid Dynamics of Radial Rim Seal

2017 ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Liming Song ◽  
Qing Gao ◽  
Xin Yan ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Gas Turbines ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Navier Stokes ◽  
Hot Gas

The modern gas turbine is widely applied in the aviation propulsion and power generation. The rim seal is usually designed at the periphery of the wheel-space and prevented the hot gas ingestion in modern gas turbines. The high sealing effectiveness of rim seal can improve the aerodynamic performance of gas turbines and avoid of the disc overheating. Effect of outer fin axial gap of radial rim seal on the sealing effectiveness and fluid dynamics was numerically investigated in this work. The sealing effectiveness and fluid dynamics of radial rim seal with three different outer fin axial gaps was conducted at different coolant flow rates using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model solutions. The accuracy of the presented numerical approach for the prediction of the sealing performance of the turbine rim seal was demonstrated. The obtained results show that the sealing effectiveness of radial rim seal increases with increase of coolant flow rate at the fixed axial outer fin gap. The sealing effectiveness increases with decrease of the axial outer fin gap at the fixed coolant flow rate. Furthermore, at the fixed coolant flow rate, the hot gas ingestion increases with the increase of the axial outer fin gap. This flow behavior intensifies the interaction between the hot gas and coolant flow at the clearance of radial rim seal. The preswirl coefficient in the wheel-space cavity is also illustrated to analyze the flow dynamics of radial rim seal at different axial outer fin gaps.

Numerical Analysis of the Flow Inside a Centrifugal Compressor’s Vaneless Diffuser and Volute

2001 ◽  
Author(s):  
Hooman Rezaei ◽  
Abraham Engeda ◽  
Paul Haley
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Mass Flow ◽  
Operating Conditions ◽  
Vaneless Diffuser ◽  
Flow Angle ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Minimum Medium ◽  
Good Agreement

Abstract The objective of this work was to perform numerical analysis of the flow inside a modified single stage CVHF 1280 Trane centrifugal compressor’s vaneless diffuser and volute. Gambit was utilized to read the casing geometry and generating the vaneless diffuser. An unstructured mesh was generated for the path from vaneless diffuser inlet to conic diffuser outlet. At the same time a meanline analysis was performed corresponding to speeds and mass flow rates of the experimental data in order to obtain the absolute velocity and flow angle leaving the impeller for those operating conditions. These values and experimental data were used as inlet and outlet boundary conditions for the simulations. Simulations were performed in Fluent 5.0 for three speeds of 2000, 3000 and 3497 RPM and mass flow rates of minimum, medium and maximum. Results are in good agreement with the experimental ones and present the flow structures inside the vaneless diffuser and volute.

scholarly journals Development of a new test rig for the analysis of hydrodynamic bearings for rotors of microGT

2019 ◽  
Vol 113 ◽  
pp. 03002
Author(s):  
Carlo Alberto Niccolini Marmont Du Haut Champ ◽  
Fabrizio Stefani ◽  
Paolo Silvestri
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Gas Turbines ◽  
Dynamic Interaction ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Test Rig ◽  
Small Clearance ◽  
Stiffness And Damping ◽  
Good Agreement

The aim of the present work is to design a test rig suited to investigate the dynamic interaction between rotor and hydrodynamic journal bearings in micro gas turbines (microGT), i.e. with reference to small bearings (diameter in the order of ten millimeters). Particularly, the device is capable of measuring the journal location. Therefore, the journal motion due to rotor vibrations can be displayed, in order to assess performance as well as stiffness and damping of the bearings. The new test rig is based on Bently Nevada Rotor Kit (RK), but substantial modifications are carried out. Indeed, the relative radial clearance of the original RK bearings is about 2/100, while it is in the order of 1/1000 in industrial bearings. Therefore, the same RK bearings are employed in the new test rig, but a new shaft has been designed in order to reduce the original clearance. The new shaft enables us to study the bearing behaviour for different clearances, as it is equipped with interchangeable journals. The experimental data yielded by the new test rig are compared with numerical results. These are obtained by means of a suitable finite element (FEM) code developed by our research group. It allows the Thermo Elasto-HydroDynamic (TEHD) analysis of the bearing in static and dynamic conditions. In the present paper, bearing static performances are analysed in order to assess the reliability of the journal location predictions by comparing numerical and experimental results. Such comparisons are presented for both large and small clearance bearings of original and modified RK, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance equal to 8/1000). Nevertheless, rotor alignment is quite difficult with small clearance bearings and a completely new test rig is designed for future experiments.

An Experimental Study of the Flow of R-407C in an Adiabatic Spiral Capillary Tube

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
M. K. Mittal ◽  
R. Kumar ◽  
A. Gupta
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Capillary Tube ◽  
Flow Characteristics ◽  
Flow Rates ◽  
Tube Test ◽  
Mass Flow Rates ◽  
R 134A

The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

Theoretical Model of the Spanwise Mixing Caused by Periodic Incoming Wakes

1994 ◽  
Author(s):  
K. Imanari
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Single Stage ◽  
Mixing Coefficients ◽  
Predicted Values ◽  
Good Agreement ◽  
Axial Flow Compressors

A theoretical model is proposed for the spanwise mixing caused by periodic incoming wakes in the context of turbulent diffusion in axial-flow compressors prior to repeating-stage conditions. The model was used to predict the spanwise mixing coefficients across a stator of a single-stage compressor without IGVs. The correctness of the theory was demonstrated by the results that the predicted values were in good agreement with the associated experimental data.

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