scholarly journals Study on the Mechanism of a Carrier-based Engine Parts' Performance Decline and Its Impact on the Whole Engine Performance

2018 ◽  
Vol 179 ◽  
pp. 01012
Author(s):  
Wu Heng ◽  
Li Benwei ◽  
Zhao Shufan ◽  
Wang Yonghua
Keyword(s):  
High Pressure ◽  
Engine Performance ◽  
Tip Clearance ◽  
Flow Capacity ◽  
Influence Area ◽  
Time Operation ◽  
Long Time ◽  
Performance Decline ◽  
Turbulence Effect ◽  
The Impact

The technical approach "use – parts' change - engine performance change" has been adopted to study and analyse the gas unit parts' performance changes of an engine after a long time operation. The mechanism of performance decline of the turbine is analysed based on the numerical simulation, the impact of components' performance decline on overall engine performance is studied and the correlation analysis is carried out. The results show that the change of turbine tip clearance, roughness increase and surface change will lead to the enhancement of secondary flow and the increase of influence area, and the turbulence effect is strengthened, resulting in the decrease of turbine circulation capacity and efficiency. The booster ratio of high pressure compressor, the flow capacity of high pressure and low pressure turbines, the flow capacity and efficiency of fan are the major component parameters causing the overall engine performance's degradation. And it also provides theoretical basis for the prevention of engine performance's degradation and online washing of parts and the whole machine.

Sensitivity Analysis and Experimental Validation of Transient Performance Predictions for a Short-Range Turbofan

2016 ◽  
Author(s):  
Maria V. Culmone ◽  
Nicolás Garcia-Rosa ◽  
Xavier Carbonneau
Keyword(s):  
Short Range ◽  
Engine Performance ◽  
Sensitivity Study ◽  
Simulation Software ◽  
Tip Clearance ◽  
Mass Storage ◽  
Transient Effects ◽  
Transient Model ◽  
Blade Tip ◽  
The Impact

Transient effects are important features of engine performance calculations. The aim of this paper is to analyze a new, fully transient model implemented using the PRopulsion Object Oriented Simulation Software (PROOSIS) for a civil, short range turbofan engine. A transient turbofan model, including the mechanical inertia effect has been developed in PROOSIS. Specific physical effects such as heat soakage, mass storage, blade tip clearance and combustion delay have been implemented in the relevant components of PROOSIS to obtain a fully transient model. Since a large number of components are concerned by all the transient effects, an influence study is presented to determine which are the most critical effects, and in which components. Inertia represents the relevant phenomenon, followed by thermal effects, combustion delay and finally mass storage. The comparison with experimental data will provide a first validation of the model. Finally a sensitivity study is reported to assess the impact of uncertain knowledge of key input parameters in the response time prediction accuracy.

Integration of 3D-CFD Component Simulation Into Overall Engine Performance Analysis for Engine Condition Monitoring Purposes

2018 ◽  
Author(s):  
C. Klein ◽  
F. Wolters ◽  
S. Reitenbach ◽  
D. Schönweitz
Keyword(s):  
Performance Analysis ◽  
Condition Monitoring ◽  
Guide Vane ◽  
Engine Performance ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Inlet Guide Vane ◽  
Cfd Model ◽  
The Impact ◽  
Engine Condition

For an efficient detection of single or multiple component damages, the knowledge of their impact on the overall engine performance is crucial. This knowledge can be either built up on measurement data, which is hardly available to non-manufacturers or –maintenance companies, or simulative approaches such as high fidelity component simulation combined with an overall cycle analysis. Due to a high degree of complexity and computational effort, overall system simulations of jet engines are typically performed as 0-dimensional thermodynamic performance analysis, based on scaled generic component maps. The approach of multi-fidelity simulation, allows the replacement of single components within the thermodynamic cycle model by higher-order simulations. Hence, the component behavior becomes directly linked to the actual hardware state of the component model. Hereby the assessment of component deteriorations in an overall system context is enabled and the resulting impact on the overall system can be quantified. The purpose of this study is to demonstrate the capabilities of multi fidelity simulation in the context of engine condition monitoring. For this purpose, a 0D-performance model of the IAE-V2527 engine is combined with a CFD model of the appropriate fan component. The CFD model comprises the rotor as well as the outlet guide vane of the bypass and the inlet guide vane of the core section. As an exemplarily component deterioration, the fan blade tip clearance is increased in multiple steps and the impact on the overall engine performance is assessed for typical engine operating conditions. The harmonization between both simulation levels is achieved by means of an improved map scaling approach using an optimization strategy leading to practicable simulation times.

Impact of Main and Splitter Blade Leading Edge Contour on the Performance of High Pressure Ratio Centrifugal Compressors

2014 ◽  
Author(s):  
Rodrigo R. Erdmenger ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Operating Range ◽  
High Pressure Ratio ◽  
The Impact ◽  
Blade Leading Edge

The impact of leading edge sweep in an attempt to reduce shock losses and extend the stall margin on axial compressors has been extensively studied, however only a few studies have looked at understanding the impact of leading edge contouring on the performance of centrifugal compressors. The present work studies the impact of forward and aft sweep on the main and splitter blade leading edge of a generic high flow coefficient and high pressure ratio centrifugal compressor design and the impact on its overall peak efficiency, pressure ratio and operating range. The usage of aft sweep on the main blade led to an increase of the pressure ratio and efficiency, however it also led to a reduction of the stable operating range of the impeller analyzed. The forward sweep cases analyzed where the tip leading edge was displaced axially forward showed a slight increase in pressure ratio, and a significant increase on operating range. The impact of leading edge sweep on the sensitivity of the impeller performance to tip clearance was also studied. The impeller efficiency was found to be less sensitive to an increase of tip clearance for both aft and forward sweep cases studied. The forward sweep cases studied also showed a reduced sensitivity from operating range to tip clearance. The studies conducted on the splitter leading edge profile indicate that aft sweep may help to increase the operating range of the impeller analyzed by up to 16% while maintaining similar pressure ratio and efficiency characteristics of the impeller. The improvement of operating range obtained with the leading edge forward sweep and splitter aft sweep was caused by a reduction of the interaction of the tip vortex of the main blade with the splitter tip, and a reduction of the blockage caused by this interaction.

Gradient-Based Adjoint and Design of Experiment CFD Methodologies to Improve the Manufacturability of High Pressure Turbine Blades

2016 ◽  
Author(s):  
Giulio Zamboni ◽  
Gabriel Banks ◽  
Simon Bather
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Correlation Factor ◽  
Control Points ◽  
High Pressure Turbine ◽  
Flow Capacity ◽  
Profile Tolerance ◽  
The Impact

The tolerance of a turbine blade aerofoil is determined by the requirements to achieve an aerodynamic performance in operation. In fact, the manufacturing tolerance applied to the profile is driven by the effects of geometrical non-conformances on the efficiency and flow capacity of the aerofoil. However, this tolerance also has an impact on the ease with which the aerofoil can be manufactured, with tighter tolerance leading to lower manufacturing conformity. This paper details the application of an adjoint RANS solver and the according series of Design of Experiments (DoE) CFD calculations for a high pressure turbine blade to the above problem. There are two aims of this work; the first is to show that simpler linear CFD perturbation can be used to evaluate the effect of the geometric non-conformance. The second is to validate the spatial geometric correlation factor of the control points used in the manufacturing process on the performance evaluation with DoE techniques. This also verified the applicability of the adjoint CFD techniques; in fact the adjoint CFD calculation is an order of magnitude less computationally expensive than a large series of DoE RANS CFD calculations. The results confirm that the peak suction area is the most critical control region for the effect on the efficiency and flow capacity. Moreover, the CFD investigations show that a significant level of correlation exists between the influence factors at different control points. This suggests that not only the amount of geometric deviation but also the stream surface variation of profile tolerance significantly influence the final aerodynamic performance. The results from this calculation allow the creation of a 3D sensitivity map which will be used during the manufacturing of the aerofoil to optimise the control of the spatial distribution of the geometric non-conformance and to directly assess the expected performance effect during the manufacturing quality inspection. The methodology detailed in this paper shows how the CFD adjoint methods could be used for improved manufacturability of turbine blades ensuring that the critical characteristic features are controlled on the surface, relaxing the profile tolerance on those surface areas where the impact on the aerodynamic performance is predicted to be lower.

scholarly journals Influence of combined compressor and turbine deterioration on the overall performance of a jet engine using RANS simulation and Pseudo Bond Graph approach

2020 ◽  
Vol 4 ◽  
pp. 296-308
Author(s):  
Jan Goeing ◽  
Hendrik Seehausen ◽  
Vladislav Pak ◽  
Sebastian Lueck ◽  
Joerg R. Seume ◽  
...  
Keyword(s):  
High Pressure ◽  
Differential Equations ◽  
Tip Clearance ◽  
System Stability ◽  
Simplified Model ◽  
Jet Engine ◽  
High Pressure Compressor ◽  
Overall Performance ◽  
The Impact ◽  
Pressure Compressor

In this study, numerical models are used to analyse the influence of isolated component deterioration as well as the combination of miscellaneous deteriorated components on the transient performance of a high-bypass jet engine. For this purpose, the aerodynamic impact of major degradation effects in a high-pressure compressor (HPC) and turbine (HPT) is modelled and simulated by using 3D CFD (Computational Fluid Dynamics). The impact on overall jet engine performance is then modelled using an 1D Reduced Order Model (ROM). Initially, the HPC performance is investigated with a typical level of roughness on vanes and blades and the HPT performance with an increasing tip clearance. Subsequently, the overall performance of the jet engines with the isolated and combined deteriorated domains is computed by the in-house 1D performance tool ASTOR (AircraftEngine Simulation for Transient Operation Research). Degradations have a significant influence on the system stability and transient effects. In ASTOR, a system of differential equations including the equations of motion and further ordinary differential equations is solved. Compared to common ROMs, this enables a higher degree of accuracy. The results of temperature downstream of the high-pressure compressor and low-pressure turbine as well as the specific fuel composition and the HP rotational speed are used to estimate the degree and type of engine deterioration. However, the consideration of the system stability is necessary to analyse the characterisation in more detail. Finally, a simplified model which merges two engines with individual deteriorated domains into one combined deteriorated engine, is proposed. The simplified model predicts the performance of an engine which has been simulated with combined deteriorated components.

Pre-Stall Disturbances and Stall Inception for an Eccentric Low-Speed Axial Compressor with Inlet Swirl

2020 ◽  
Author(s):  
Xuegao Wang ◽  
Jun Hu ◽  
Jin Guo ◽  
Chao Jiang ◽  
Zhiqiang Wang
Keyword(s):  
Axial Compressor ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Stall Inception ◽  
Stall Margin ◽  
Flow Unsteadiness ◽  
Time Operation ◽  
Long Time ◽  
Inlet Swirl ◽  
Assembly Error

Abstract Owing to the manufacturing and assembly error or the fatigue of long-time operation, nonaxisymmetric tip clearance is actually a common phenomenon in compressors. It's also well accepted that tip leakage flow, associated with tip clearance size and loading, has a strong influence on the performance and stall inception of compressors. The work of this paper, based on an eccentric compressor with/without inlet swirl distortion, is aimed at strengthening the understanding of stall inception for a real geometry compressor experimentally. Results indicate that rotor tip blockage and flow unsteadiness vary evidently around the circumference. For this compressor, the maximum tip flow unsteadiness and blockage happens at the location near the minimum clearance under the condition of clean inlet flow. Before the occurrence of stall inception, disturbances arise and vanish intermittently within the region of high unsteadiness. However, it fails to rotate due to the inhibition of the low unsteadiness region. Once the most robust region is no longer able to suppress disturbances, stability finally breaks down and stall inception generates. After exerted inlet paired swirl, unsteadiness within the region of positive pre-swirl decreases significantly and the maximum unsteadiness location shifts, while the increase for the region with negative pre-swirl is nearly negligible. As a result of that, stall margin of the compressor is improved.

scholarly journals The Impact of Realistic Casing Geometries and Clearances on Fan Blade Tip Aerodynamics

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Alistair John ◽  
Ning Qin ◽  
Shahrokh Shahpar
Keyword(s):  
Engine Performance ◽  
Leading Edge ◽  
Tip Clearance ◽  
Blade Design ◽  
Engine Operation ◽  
Surface Method ◽  
Flow Features ◽  
Blade Tip ◽  
Fan Blade ◽  
The Impact

During engine operation, fan casing abradable liners are worn by the blade tip, resulting in the formation of trenches. This paper describes the influence of these trenches on the fan blade tip aerodynamics. A detailed understanding of the fan tip flow features for cropped and trenched clearances is first developed. A parametric model is then used to model trenches in the casing above the blade tip and varying blade tip positions. It is shown that increasing clearance via a trench reduces performance by less than increasing clearance through cropping the blade tip. A response surface method is then used to generate a model that can predict fan efficiency for a given set of clearance and trench parameters. This model can be used to influence fan blade design and understand engine performance degradation in service. It is shown that an efficiency benefit can be achieved by increasing the amount of tip rubbing, leading to a greater portion of the tip clearance sat within the trench. It is shown that the efficiency sensitivity to clearance is biased toward the leading edge (LE) for cropped tips and the trailing edge (TE) for trenches.

scholarly journals An Engine Research Program Focused on Low Pressure Turbine Aerodynamic Performance

2002 ◽  
Author(s):  
Raymond Castner ◽  
Santo Chiappetta ◽  
John Wyzykowski ◽  
John Adamczyk
Keyword(s):  
Reynolds Number ◽  
Cfd Simulation ◽  
State Of The Art ◽  
Engine Performance ◽  
Low Pressure ◽  
Low Pressure Turbine ◽  
Flow Capacity ◽  
Comprehensive Test ◽  
The Impact ◽  
Bypass Ratio

A comprehensive test program was performed in the Propulsion Systems Laboratory at the NASA Glenn Research Center, Cleveland Ohio using a highly instrumented Pratt and Whitney Canada PW 545 turbofan engine. A key objective of this program was the development of a high-altitude database on small, high-bypass ratio engine performance and operability. In particular, the program documents the impact of altitude (Reynolds number) on the aero-performance of the low-pressure turbine (fan turbine). A second objective was to assess the ability of a state-of-the-art CFD code to predict the effect of Reynolds number on the efficiency of the low-pressure turbine. CFD simulation performed prior and after the engine tests will be presented and discussed. Key findings are the ability of a state-of-the art CFD code to accurately predict the impact of Reynolds number on the efficiency and flow capacity of the low-pressure turbine. In addition the CFD simulations showed the turbulence intensity exiting the low-pressure turbine to be high (9%). The level is consistent with measurements taken within an engine.

Aerodynamic analysis of a supersonic expander

2020 ◽  
pp. 095765092094331
Author(s):  
Zhenyu Huang ◽  
Wanyang Wu ◽  
Ling Yang ◽  
Jingjun Zhong
Keyword(s):  
Relative Motion ◽  
Engine Performance ◽  
Significant Rise ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Transverse Motion ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Flow Losses ◽  
The Impact

In this paper, a numerical investigation was conducted into the impact of the tip clearance height and the relative motion between the casing and the strake wall tip on the tip clearance leakage flow of a supersonic expander. Besides, an analysis was carried out to characterize the flow under varying operating conditions. Numerical results show that the remarkable characteristics of motion within the tip gap region are the leakage fluid around the trailing edge passing through the tip gap and then returning to the pressure side. As the tip clearance height increases, the intensity and scale of the tip leakage vortex show an upward trend. Also, the mix with the surrounding airflow contributes to a significant increase in the leakage losses and a reduction of the losses in the rampart and the mainstream region. It can be found that an excellent aerodynamic performance will be achieved when the tip clearance height ranges between 0.9% h0 and 1.5% h0. The relative motion of the casing not only reduces the transverse motion of the leakage vortex but also increases the tip leakage mass flow and the intensity of the tip leakage vortex, thus causing a significant rise in the flow losses. A lower [Formula: see text] will result in a severe deterioration in the performance of the supersonic expander. Furthermore, when the [Formula: see text] reaches a certain threshold (or above 12 times the atmospheric pressure to be precise), the main performance parameters of the supersonic expander will show no change with the increase of [Formula: see text]. Nevertheless, the continued improvement of [Formula: see text] means that the requirement becomes more demanding on engine performance.

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