scholarly journals Impact of Front- and Rear-Stage High Pressure Compressor Deterioration on Jet Engine Performance

Author(s):  
Gerald Reitz ◽  
Jens Friedrichs
2021 ◽  
Vol 6 (2) ◽  
pp. 50-55
Author(s):  
Wildan Sofary Darga ◽  
Edy K. Alimin ◽  
Endah Yuniarti

Exhaust Gas Temperatue is an parameter where the hot gases’s temperature leave the gas turbine. Exhaust gas temperature margin is the difference between highest temperature at take off phase with redline on indicator (???????????? ???????????????????????? °????=???????????? ????????????????????????????−???????????? ???????????????? ????????????). EGTM is one of any factor to determine engine performance. A good perfomance of an engine when it has a big margin (EGTM), during operation of an engine the EGTM could decrease untill 0 (zero). So many factors could affect EGTM deteroration there are: distress hardware such as airfoil erosion, leak of an airseals, and increase of clearance between tip balde and shroud. Increase of clearance happens in high pressure compressor rotor clearance. In CFM56-7 have 9 stage(s) of high pressure compressor and each stage give the EGT Loses. The calculation of EGT Effect/Losses is actual celarance – minimum clearance x 1000 x EGT Effect °C, where actual clearance define by the substraction of outside diameter’s rotor with inside diameter’s shroud, minimum clearance define in the manual, 1000 is adjustment from mils/microinch to inch, and EGT Effect is temperature that define in the manual. The analysist had done with 6 (six) engine serial number and proceed by corelation that shown linkage between clearance and EGT Effect, the corelation is strong shown the result of corelation (r) is 0.994275999 or nearest 1.


2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Wolfgang Horn ◽  
Klaus-Jürgen Schmidt ◽  
Stephan Staudacher

This analytical study discusses the system aspects of active stability enhancement using mass flow injection in front of the rotor blade tip of a high pressure compressor. Tip injection is modeled as a recirculating bleed in a performance simulation of a commercial turbofan engine. A map correction procedure accounts for the changes in compressor characteristics caused by injection. The correction factors are derived from stage stacking calculations, which include a simple correlation for stability enhancement. The operational characteristic of the actively controlled engine is simulated in steady and transient states. The basic steady-state effect consists of a local change in mass flow and a local increase in gas temperature. This alters the component matching in the engine. The mechanism can be described by the compressor-to-turbine flow ratio and the injection temperature ratio. Both effects reduce the cycle efficiency resulting in an increased turbine temperature and fuel consumption at constant thrust. The negative performance impact becomes negligible if compressor recirculation is only employed at the transient part power and if valves remain closed at the steady-state operation. Detailed calculations show that engine handling requirements and temperature limits will still be met. Tip injection increases the high pressure compressor stability margin substantially during critical maneuvers. The proposed concept in combination with an adequate control logic offers promising benefits at transient operation, leading to an improvement potential for the overall engine performance.


Author(s):  
N. Lecerf ◽  
D. Jeannel ◽  
A. Laude

Reducing costs and development times are two of the main challenges for aircraft engines manufacturers. Analysis shows that the main troubles encountered during the industrialization phase are due to choices made during the first steps, such as the preliminary design of the compressor throughflow (flowpath and velocity triangles). Therefore, constraints and needs from the later phases have to be taken into account as early as possible. A deterministic optimization method for automated compressor throughflow design has been developed to achieve these objectives, improving efficiency and surge margin while modifying the design parameters. Nevertheless, variability between the theoretical geometry and the actual one may occur because of the manufacturing process or the damages encountered during the engine life cycle. Depending on their magnitude, these differences can affect the engine performance. To consider these random phenomena from the design step, the deterministic optimization is coupled with a probabilistic approach, based on a robust design methodology which aims at guarantee the engine performance despite geometrical variability. This article deals with geometrical robustness. It presents a robust design methodology and introduces a capability function used to optimize the outputs of a compressor model while minimizing their standard deviation. The model has two kinds of inputs: the design factors, which are known by both designer and manufacturer, and the noise factors, that are just known by their mean value and their standard deviation. As robust design requires a large number of calculations, it is interesting to work with an approximated physical model such as a response surface, generated through the computation of a suitable design of experiments. This method has been successfully applied to the design of a Snecma Moteurs high-pressure compressor.


Author(s):  
Wolfgang Horn ◽  
Klaus-Ju¨rgen Schmidt ◽  
Stephan Staudacher

This analytical study discusses the system aspects of active stability enhancement using mass flow injection in front of the rotor blade tip of a high pressure compressor. Tip injection is modeled as a recirculating bleed in a performance simulation of a commercial turbofan engine. A map correction procedure accounts for the changes in compressor characteristics caused by injection. The correction factors are derived from stage stacking calculations which include a simple correlation for stability enhancement. The operational characteristic of the actively controlled engine is simulated in steady and transient states. The basic steady-state effect consists of a local change in mass flow and a local increase in gas temperature. This alters the component matching in the engine. The mechanism can be described by the compressor-to-turbine flow ratio and the injection temperature ratio. Both effects reduce the cycle efficiency resulting in increased turbine temperature and fuel consumption at constant thrust. The negative performance impact becomes negligible if compressor recirculation is only employed at transient part power and if valves remain closed at steady-state operation. Detailed calculations show that engine handling requirements and temperature limits will still be met. Tip injection increases the high pressure compressor stability margin substantially during critical maneuvers. The proposed concept in combination with an adequate control logic offers promising benefits at transient operation, leading to an improvement potential for overall engine performance.


Author(s):  
Gerald Reitz ◽  
Andreas Kellersmann ◽  
Jens Friedrichs

The Institute of Jet Propulsion and Turbomachinery of the TU Braunschweig owns a jet engine of the type V2500-A1 from the International Aero Engines AG. To conduct research on the jet engine and its components, computer models are necessary. In this paper, the reverse engineering process of the high pressure compressor (HPC) regarding its aerodynamics is presented. Thereby, the reverse engineering process starts from digitizing newly manufactured airfoils, followed by FEM-calculations to enforce the operating forces on the geometries. A computational fluid dynamics (CFD) model using these geometries is set up, considering all relevant geometric and aerodynamic features such as bleed ports and the variable stator vane (VSV) system. Using this CFD-model, the compressor map is calculated and afterwards validated by available manufacturing data [18] and by the institute’s jet engine’s test cell data. Because this jet engine is a highly operated and deteriorated one, a map scaling is necessary before comparing the CFD-model with the test cell data. Nevertheless, an adequate agreement of the operating behavior between scaled compressor map and test cell data is shown. To estimate the deterioration level of the jet engine’s compressor and to evaluate the used scaling factors, the tip gaps inside the CFD-model were doubled and the compressor behavior was simulated. The observed effect of reduced compressor capacity and efficiency is in accordance with literature but is not able to explain the amount of the scaling factors completely.


2020 ◽  
Vol 4 ◽  
pp. 296-308
Author(s):  
Jan Goeing ◽  
Hendrik Seehausen ◽  
Vladislav Pak ◽  
Sebastian Lueck ◽  
Joerg R. Seume ◽  
...  

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.


2017 ◽  
Vol 4 (17) ◽  
pp. 91-97
Author(s):  
Adam KOZAKIEWICZ ◽  
Olga GRZEJSZCZAK ◽  
Tomasz LACKI

The article concerns the issues of the scope of optimization of the gas turbine jet engine. These issues include limiting the weight and number of engine parts. One way to reduce the weight and number of components, including the compressor assembly, is to use the BLISK's replacement construction. The replacement construction should meet the strength requirement and the vibration spectrum as well. The paper presents a comparative analysis of the influence of rotational speed on the characters and the vibration frequency of the single rotor stage of the high pressure compressor. The analysis was carried out for two different design solutions of the blade-disk connection: the classical and integral. The comparative analysis focused on three important from the point of view of operation, the engine operating ranges: work on the ground (idle) and work during take-off and climb the aircraft.


Author(s):  
Gerald Reitz ◽  
Jens Friedrichs ◽  
Jonas Marx ◽  
Jörn Städing

During the operation of a jet engine, deterioration will constantly reduce its performance. This results in an increase in specific fuel consumption (SFC) and exhaust gas temperature (EGT); the main characteristics to describe the efficiency of a jet engine. Thereby, the high pressure compressor (HPC) is particularly affected by deterioration. Multiple effects take place and decrease the efficiency of the HPC. Erosion is one of the main effects and leads to thinner or thicker leading- and trailing edges, thinner airfoils, a reduction of chord length and an increase in tip clearance. In addition, erosion and fouling may also lead to increased surface roughness on airfoils and endwalls. An additional parameter which is also dependent on the on-wing time are changes in the stagger angle of the different blade heights. The objective is to estimate the quantitative effect of the different wear mechanisms on the stage parameters, like throttle line and efficiency. Therefore, a geometry setup process is implemented to create HPC blade models with independent values of erosion. With these blades, CFD calculations based on realistic boundary conditions were carried out with the CFD solver ANSYS CFX. It could be proven that the deterioration of leading edge thickness has the major influence on stage performance, followed by the max. profile thickness and the stagger angle. The operational blade deterioration of leading edge thickness leads to an efficiency range of about 0.173 %. Moreover, the deterioration of stagger angle leads to an offset of the throttle lines towards higher or smaller loadings, depending on the direction of change.


2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.


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