Experiments on Aft-Disk Cavity Ingestion in a Model 1.5-Stage Axial-Flow Turbine

2011 ◽  
Author(s):  
J. Balasubramanian ◽  
N. Junnarkar ◽  
D. W. Zhou ◽  
R. P. Roy ◽  
Y. W. Kim ◽  
...  
Keyword(s):  
Velocity Field ◽  
Fluid Velocity ◽  
Air Flow ◽  
Axial Flow ◽  
Initial Step ◽  
Labyrinth Seal ◽  
Radial Clearance ◽  
Main Stream ◽  
Flow Rates ◽  
Secondary Air

Experiments were carried out in a model 1.5-stage (vane-blade-vane) axial-flow air turbine to investigate the ingestion of main-stream air into the aft disk cavity. This cavity features rotor and stator rim seals with radial clearance and axial overlap, and an inner labyrinth seal. Results are reported for two main air flow rates, two rotor speeds, and three purge (secondary) air flow rates. The initial step at each experimental condition was the measurement of time-average static pressure distribution in the turbine stage to ensure that a nominally steady run condition had been achieved. Subsequently, tracer gas concentration and particle image velocimetry (PIV) techniques were employed to measure, respectively, the main gas ingestion into the disk cavity (rim and inner parts) and the fluid velocity field in the rim cavity. Finally, the egress trajectory of the purge air into the main-stream air was mapped in the axial-radial plane by PIV at multiple circumferential positions within one aft vane pitch. The purge air egress trajectory and velocity field are important because the interaction of this air with the main gas stream has aerodynamic, stage performance, and downstream vane/endwall heat transfer implications.

Experiments on Front- and Aft- Disk Cavity Ingestion in a Subscale 1.5-Stage Axial Turbine

2016 ◽  
Author(s):  
J. Balasubramanian ◽  
M. Michael ◽  
R. P. Roy ◽  
Y. W. Kim ◽  
H. K. Moon
Keyword(s):  
Air Flow ◽  
Co2 Concentration ◽  
Initial Step ◽  
Labyrinth Seal ◽  
Radial Clearance ◽  
Tracer Gas ◽  
Experimental Conditions ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Mass Flow Rates

This paper describes experiments performed in a subscale 1.5-stage axial air turbine in which ingestion of mainstream air into the front and aft disk cavities was measured. The front disk cavity is upstream of the rotor, the aft disk cavity is downstream of the rotor. Both disk cavities contain a labyrinth seal at a radially inboard location; this seal divides the cavity into a ‘rim cavity’ and an ‘inner cavity’. The front rim cavity features a double seal with radial clearance and axial overlap at its periphery; the aft rim cavity double seal possesses axial gap. Results are reported for three experiment sets, each set defined by the main air flow rate and rotor speed. Furthermore, each set comprises four different purge air flow rates. The initial step in each experiment was the measurement of time-average static pressure distribution in the main gas annulus and the disk cavities to establish the steady-state pressure differentials that contribute to ingestion into and egress from the cavities. This was followed by the measurement of tracer gas (CO2) concentration distribution in the disk cavities to quantify the ingestion. In addition to the pressure and concentration (in terms of sealing effectiveness) results, the mass flow rates of ingested main air into the front and aft rim cavities are reported for the various experimental conditions. Both inner cavities were found to be completely sealed against ingestion. Ingestion and egress discharge coefficients based on an orifice model are reported for the front and aft double rim seals; their trends are quite different from those of single rim seals with axial overlap and radial clearance reported earlier.

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

The Effects of Air Flow Rates, Secondary Air Inlet Geometry, Fuel Type, and Operating Mode on the Performance of Gasifier Cookstoves

2016 ◽  
Vol 50 (17) ◽  
pp. 9754-9763 ◽  
Author(s):  
Jessica Tryner ◽  
James W. Tillotson ◽  
Marc E. Baumgardner ◽  
Jeffrey T. Mohr ◽  
Morgan W. DeFoort ◽  
...  
Keyword(s):  
Air Flow ◽  
Operating Mode ◽  
Fuel Type ◽  
Flow Rates ◽  
Air Inlet ◽  
Inlet Geometry ◽  
Secondary Air

Calculation of the Parameters of Combustion Products of Sewage Sludge

2018 ◽  
Vol 22 (6) ◽  
pp. 54-57
Author(s):  
A.V. Demin ◽  
R.Ya. Dyganova ◽  
V.P. Shipkov ◽  
R.R. Valiev
Keyword(s):  
Sewage Sludge ◽  
Phase Equilibria ◽  
Air Flow ◽  
Combustion Products ◽  
Flow Rates ◽  
Optimal Ratio ◽  
Secondary Air

The problems associated with the use of existing thermal installations for the incineration of sewage sludge and the design of new structures are considered. The results obtained by calculating the chemical and phase equilibria are presented. Recommended optimal ratio of primary and secondary air flow rates with its step-by-step approach.

scholarly journals Calculation of Labyrinth Seals in the Secondary Air System of Aircraft Engine

2014 ◽  
Vol 8 (1) ◽  
pp. 424-430 ◽  
Author(s):  
Andrei Tisarev ◽  
Sergei Falaleev ◽  
Alexandr Vinogradov
Keyword(s):  
Aircraft Engine ◽  
Labyrinth Seal ◽  
Radial Clearance ◽  
Cylindrical Shape ◽  
Labyrinth Seals ◽  
High Pressure Compressor ◽  
Mutual System ◽  
Air System ◽  
Secondary Air ◽  
Engine Systems

The labyrinth seals perform the important functions in the aircraft engine systems operation, which aim to reduce the air leakages and the mutual system interference reduction. The calculation of the labyrinth seal characteristics is performed simply by using the analytical relationships or the modern tools of numerical analysis. However, the seal operation specificity within the system of operating engine secondary streams imposes some additional difficulties manifested in the rotor and stator elements deformation forming a gap. In this paper, we analyzed the formation cases of axis symmetric and asymmetric forms of labyrinth seal gaps. For the case of symmetrical cone gaps formation the correction factors were obtained by using the Fluent analysis to assess the seal characteristics with the conical form of the gaps, compared with the seal with cylindrical shape concentric gaps at the minimum radial clearance. The algorithm of axis symmetric seal deformation at the calculation of the engine secondary air system is described. The asymmetric components of deformations for the rotor and the high-pressure compressor housing are analyzed separately. The high rigidity of the elements contributed to the emergence of low level asymmetric deformation, allowing exclude them at the calculation of the seal characteristics.

Coupled Simulation of the Secondary Air Flow, Heat Transfer, and Structural Deflection of a Gas Turbine Engine

2012 ◽  
Author(s):  
Guilherme Tondello ◽  
Wolodymir Boruszewski ◽  
Fernando Mengele ◽  
Marcelo Assato ◽  
Silvio Shimizu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Structural Model ◽  
Air Flow ◽  
Labyrinth Seal ◽  
Simulation Software ◽  
Thermal Loads ◽  
Labyrinth Seals ◽  
Secondary Air

In secondary air flow in gas turbines, labyrinth seals are used to control the flow to and from each cavity and to the rotor blades for cooling purposes. Those components and the final flow rate are very sensitive to gap clearance and displacement due to structural and thermal loads during operation, therefore designing those seals and knowing the resultant flow rates in each part of the circuit during the design phase is not an easy task, and tuning those gap values may bring significant increase in turbine efficiency. This paper describes the application of coupled commercial codes for secondary air flow and structural simulation for better evaluating temperature profiles and labyrinth seal behavior during operation. Flowmaster V7 was used for building a one dimensional model of the complete secondary air flow path including swirl effects and heat transfer phenomena, and ANSYS was used for building a structural model, taking into account both rotational and thermal loads. The labyrinth seals clearances, and thermal interactions between solid and fluid were coupled bi-directionally between the two simulation software. This simulation focused in the system, including the effects of each region, passage, seal and cavity in the calculations. The turbine model simulated was a VSE’s gas turbine under development, having a nominal rotation of 22600 rpm. This paper presents the numerical characteristics of each model, the details about the 1D fluid and 3D structural coupling, and the results obtained.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

Numerical study of the flow of a mixture of reacting gases in an inhomogeneous catalyst layer

2003 ◽  
Vol 3 ◽  
pp. 246-254
Author(s):  
C.I. Mikhaylenko ◽  
S.F. Urmancheev
Keyword(s):  
Velocity Field ◽  
Chemical Reactions ◽  
Porous Layer ◽  
Computational Experiment ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Catalyst Layer ◽  
Granular Catalyst ◽  
Fluid Velocity Field

The behavior of a liquid flowing through a fixed bulk porous layer of a granular catalyst is considered. The effects of the nonuniformity of the fluid velocity field, which arise when the surface of the layer is curved, and the effect of the resulting inhomogeneity on the speed and nature of the course of chemical reactions are investigated by the methods of a computational experiment.

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