Effects of Steam Ingestion on Under Fuselage Inlet Performance During a Catapult-Assisted Takeoff Process

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Yuehua Fan ◽  
Zhenxun Gao ◽  
Chongwen Jiang ◽  
Chun-Hian Lee
Keyword(s):  
Leakage Rate ◽  
Time Step ◽  
Turbine Engine ◽  
Stall Margin ◽  
Factors Affecting ◽  
Rise Rate ◽  
Time Histories ◽  
Performance Decline ◽  
Parametric Studies ◽  
Steam Leakage

A naval aircraft has the potential to experience inlet performance decline when taking off from the carrier deck with the steam-driven catapult assistance. The steam ingested into inlet may cause time-dependent rise and spatial distortion of the total temperature on the inlet–exit, which would decrease the compressor stall margin and then lower the performance of the turbine engine. In this paper, these temporal and spatial temperature nonuniformities are numerically studied using the dual-time-step transient method with a real aircraft/inlet model taken into account. The flowfield characteristics of a designed baseline case are first analyzed, indicating that the engine’s suction effect and the wind velocity relative to the aircraft are two key factors affecting the steam ingestion. The former is dominant at the beginning of takeoff since the aircraft's velocity is low, while the latter is increasingly significant as the aircraft accelerates. Next, parametric studies show that the greater the wind speed is, the less significantly the flowfield of the inlet–exit would be influenced by the steam. The effects are also studied among various steam leakage profiles—two are constant in time histories of the steam leakage rate, whereas the other two are nonlinear with the maximum value at different instants. It is found that the temperature rise rate of the inlet–exit would increase apparently if the steam leakage rate reaches the maximum earlier.

Performance Deterioration in Industrial Gas Turbines

1992 ◽  
Vol 114 (2) ◽  
pp. 161-168 ◽  
Author(s):  
I. S. Diakunchak
Keyword(s):  
Gas Turbine ◽  
Service Time ◽  
Gas Turbines ◽  
Engine Performance ◽  
Turbine Engine ◽  
Factors Affecting ◽  
Preventative Measures ◽  
Industrial Gas Turbines ◽  
Performance Deterioration ◽  
Industrial Gas Turbine

This paper describes the most important factors affecting the industrial gas turbine engine performance deterioration with service time and provides some approximate data on the prediction of the rate of deterioration. Recommendations are made on how to detect and monitor the performance deterioration. Preventative measures, which can be taken to avoid or retard the performance deterioration, are described in some detail.

A Numerical Study of Labyrinth Seal Flutter

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
L. di Mare ◽  
M. Imregun ◽  
J. S. Green ◽  
A. I. Sayma
Keyword(s):  
Numerical Study ◽  
Large Diameter ◽  
Labyrinth Seal ◽  
Navier Stokes ◽  
Time Step ◽  
Modal Model ◽  
Flutter Analysis ◽  
Time Histories ◽  
Structural Motion ◽  
Good Agreement

A numerical study of a labyrinth-type turbine seal flutter in a large turbofan engine is described. The flutter analysis was conducted using a coupled fluid-structure interaction code, which was originally developed for turbomachinery blade applications. The flow model is based on an unstructured, implicit Reynolds-averaged Navier–Stokes solver. The solver is coupled to a modal model for the structure obtained from a standard structural finite element code. During the aeroelasticity computations, the aerodynamic grid is moved at each time step to follow the structural motion, which is due to unsteady aerodynamic forces applied onto the structure by the fluid. Such an integrated time-domain approach allows the direct computation of aeroelastic time histories from which the aerodynamic damping, and hence, the flutter stability, can be determined. Two different configurations of a large-diameter aeroengine labyrinth seal were studied. The first configuration is the initial design with four fins, which exhibited flutter instability during testing. The second configuration is a modified design with three fins and a stiffened ring. The steady-state flow was computed for both configurations, and good agreement was reached with available reference data. An aeroelasticity analysis was conducted next for both configurations, and the model was able to predict the observed flutter behavior in both cases. A flutter mechanism is proposed, based on the matching of the structural frequencies to the frequencies of waves traveling in the fluid, in the interfin cavities and in the high- and low-pressure cavities.

Automated Multi-Code URANS Simulation of Compressor-Combustor Components

2016 ◽  
Author(s):  
K. V. Kannan ◽  
G. J. Page
Keyword(s):  
Hot Wire ◽  
Time Step ◽  
Flow Solver ◽  
Turbine Engine ◽  
Integrated Simulation ◽  
Cold Flow ◽  
Unsteady Simulation ◽  
Simulation Results ◽  
Inlet Conditions ◽  
Spatially Varying

Currently in an aircraft gas turbine engine, the turbomachinery and combustor components are designed in relative isolation and the effect of the upstream and downstream components on each other’s flow are not fully captured in the design process. The objective of this work is to carry out a multi-code integrated unsteady simulation of Compressor-Combustor components with each zone simulated using its own specialised CFD flow solver. The multi-code URANS technique is simple, based on files and involves the generation of new 2D boundary conditions for the required flow field at each time step. A driver based on a Python script automates the entire process. This paper shows the method first validated in a simple vortex shedding 2D case and then extended to a cold flow URANS simulation matching an isothermal compressor/combustor rig experiment. An external coupler code is invoked that produces unsteady, spatially varying, inlet conditions for the downstream components. The simulation results are encouraging as the mass, momentum and energy losses across the interface are less than 1%. The multi-code unsteady simulation produces wake profiles closer to the experiment than the coupled steady RANS simulation. The present study shows a reasonable agreement with the experimental PIV and hot-wire data thus demonstrating the potential of the multi-code integrated simulation technique.

scholarly journals Justifications for an All-Radial 1600-HP Gas Turbine Engine

1970 ◽  
Author(s):  
R. J. Mowill
Keyword(s):  
Gas Turbine ◽  
Low Cost ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Factors Affecting ◽  
Engine Development

The philosophy and justifications behind a large all-radial single-shaft gas turbine engine development are discussed. In addition, some of the factors affecting the marketing of a simple and low cost engine are dealt with.

Performance Deterioration in Industrial Gas Turbines

1991 ◽  
Author(s):  
Ihor S. Diakunchak
Keyword(s):  
Gas Turbine ◽  
Service Time ◽  
Gas Turbines ◽  
Engine Performance ◽  
Turbine Engine ◽  
Factors Affecting ◽  
Preventative Measures ◽  
Industrial Gas Turbines ◽  
Performance Deterioration ◽  
Industrial Gas Turbine

This paper describes the most important factors affecting the industrial gas turbine engine performance deterioration with service time and provides some approximate data on the prediction of the rate of deterioration. Recommendations are made on how to detect and monitor the performance deterioration. Preventative measures, which can be taken to avoid or retard the performance deterioration, are described in some detail.

A Quasi-Vehicle/Bridge Interaction Model for High Speed Railways

2015 ◽  
Vol 31 (2) ◽  
pp. 217-225 ◽  
Author(s):  
J.-D. Yau ◽  
L. Frýba
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Interaction Model ◽  
Time History ◽  
Time Step ◽  
Moving Vehicle ◽  
Coupled Equations ◽  
History Analysis ◽  
High Speed Trains ◽  
Parametric Studies

ABSTRACTVehicle response is served as a reference to evaluate riding comfort of passengers and running safety of moving carriages for high speed trains. In analyzing the vehicle-bridge interaction (VBI) problems, two sets of coupled equations of motion for running vehicles and bridge need to be solved and the VBI system matrices must be updated and factorized at each time step in a time-history analysis. This paper proposed a quasi-VBI model to abridge the complicated computational process, in which the bridge is subjected to only moving static forces of the train loadings, and the moving vehicle over it is excited by the corresponding feedback bridge response. To examine the interacting degree of the vehicle with the bridge, a coupling evaluation index (CEI) is defined as a quantitative assessment of the VBI system. The numerical parametric studies reveal that (1) the mass ratio of vehicle to bridge is the most sensitive parameter affecting the bridge response; (2) increasing bridge damping can reduce the coupling degree of the VBI system at high speeds; (3) the present quasi-VBI model is an efficient and simple tool to predict the vehicle's response with enough accuracy based on engineering approximation.

A Simple Leakage Flow Model Including Viscous Effect

2011 ◽  
Author(s):  
Yuping Qian ◽  
Jian Cui ◽  
Chaoqing Chen ◽  
Yifang Gong ◽  
Qiushi Li
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Leakage Flow ◽  
Viscous Effect ◽  
Tip Leakage Flow ◽  
Stall Margin ◽  
Factors Affecting ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Leakage Flow Rate

The tip leakage flow rate can be directly linked to the loss and stall margin. In this paper, key factors affecting the tip leakage flow rate are explained based on a simple leakage flow model including viscous effect. Based on the numerical results, the flow model is verified in a low speed compressor rotor, and finally a simplified one-dimensional tip blockage model is established based on the Khalid’s model, which may be helpful in the design of compressor.

Practical Modeling for Articulated Risers and Loading Columns

1984 ◽  
Vol 106 (4) ◽  
pp. 444-450 ◽  
Author(s):  
J. F. McNamara ◽  
M. Lane
Keyword(s):  
Ship Motions ◽  
Random Waves ◽  
Efficient Design ◽  
Time Step ◽  
Design Studies ◽  
Large Rotations ◽  
Parametric Studies ◽  
Element Approach ◽  
Large Time Step ◽  
Nonlinear Static

An efficient method for the analysis of the linear and nonlinear static and dynamic motions of offshore systems such as risers and single-leg mooring towers is presented. The technique is based on the finite element approach using connected coordinates for arbitrary large rotations and includes terms due to loads such as buoyancy, gravity, random waves, currents, ship motions and Morison’s equation. Practical features include the addition of intermediate articulations and modeling of the loading arm between the riser and associated tanker. Parametric studies are presented to show that stable and accurate results are obtained using relatively large time step increments leading to efficient design studies.

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