Comparison of sensitivities to geometrical properties of front and aft high pressure compressor stages

2018

IJTPP

The decreasing performance of jet engines during operation is a major concern for airlines and maintenance companies. Among other effects, the erosion of high-pressure compressor (HPC) blades is a critical one and leads to a changed aerodynamic behavior, and therefore to a change in performance. The maintenance of BLISKs (blade-integrated-disks) is especially challenging because the blade arrangement cannot be changed and individual blades cannot be replaced. Thus, coupled deteriorated blades have a complex aerodynamic behavior which can have a stronger influence on compressor performance than a conventional HPC. To ensure effective maintenance for BLISKs, the impact of coupled misshaped blades are the key factor. The present study addresses these effects on the aerodynamic performance of a first-stage BLISK of a high-pressure compressor. Therefore, a design of experiments (DoE) is done to identify the geometric properties which lead to a reduction in performance. It is shown that the effect of coupled variances is dependent on the operating point. Based on the DoE analysis, the thickness-related parameters, the stagger angle, and the max. profile camber as coupled parameters are identified as the most important parameters for all operating points.

Section: Blisk Blade Deteriorationmentioning

confidence: 72%

“…The loss coefficient was mostly influenced by the thickness-related parameters of the leading edge. A comparison of different deteriorated stages and their influence was also done by Reitz et al [7]. Here they showed that the sensitivities changed because of different Mach number of the incoming flow.…”

Section: Introductionmentioning

confidence: 82%

Sensitivity Analysis of BLISK Airfoil Wear

Kellersmann

2018

IJTPP

“…This process delivers the parameters listed in Table 1 for every 2D-profile. The geometric parameters are explained by Reitz and Friedrichs (2015) and in Reitz et al (2018). To focus only on geometric variances of the blade profile, the hub and tip region are neglected, despite of their influence.…”

Section: Blisk Wearmentioning

confidence: 99%

“…The same applies to the trailing edge. Thereby, the parameter LE stretch and TE stretch define a ratio of a length, which is 1% of the chord length with the thickness measured at 1% chord length (Reitz et al, 2018). If a thicker edge parameter appears, the edge stretching is decreasing.…”

Section: Design Of Experimentsmentioning

confidence: 99%

Deterioration effects of coupled blisk blades

Kellersmann

J. Glob. Power Propuls. Soc.

2018

Performance degradation due to wear of high pressure compressors (HPC) is a major concern in aero-engine operation and maintenance. Among other effects especially erosion of airfoils leads to changed aerodynamic behavior and therefore to deterioration. These affects engine performance parameter like thrust specific fuel consumption (TSFC) and exhaust gas temperature (EGT). Reaching EGT-limit, the engine typically has to be overhauled during a shop visit to restore safety standards and performance. During state of the art shop visits, engines are repaired based on EGT-specifications. To further enhance the maintenance, tailored repairs for each jet engine based on engine history and operation conditions are necessary to take TSFC into account. To ensure such an effective maintenance, the aerodynamic behavior of deteriorated and repaired airfoils is the key factors. Therefore, geometric properties with high influence on aerodynamic performance have to be known. For blisks (BLade-Integrated-diSK) the approach of tailored maintenance will be even more complicated because the airfoil arrangement cannot be changed or individual airfoils cannot be replaced. Thus, the effects of coupled misshaped airfoils have a high significance. This study will present a Design of Experiments (DoE) for circumferential coupled HPC-airfoils to identify the geometric properties which lead to a reduction of performance. To focus on geometric variations, quasi3D (Q3D) simulations are taken out. Based on a sensitivity analysis, the thickness related parameters, the stagger angle as well as the max. profile camber thickness are identified as the most important parameters which are influencing adjacent airfoils and reduce the aerodynamic performance.

“…Subsequently, aerodynamic sensitivities of the geometric properties were investigated using computational fluid dynamic (CFD)-methods. Therefore, extensive Design of Experiments (DoE) for the front and rear stages have been carried out [3,4]. To reduce the number of independent geometric properties, the geometric parameters have previously been scanned for possible correlations [5].…”

Section: Introductionmentioning

confidence: 99%

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

2018

IJTPP

Current civil aviation is characterized by rising cost and competitive pressure, which is partly passed to the MRO (Maintenance, Repair and Overhaul) companies. To improve the maintenance, condition-based maintenance is established, which is characterized by tailored maintenance actions for each part of the jet engine, depending on the individual engine history and operating conditions. Thereby, prediction models help engineers to authorize maintenance actions as effectively as possible. This paper will help to improve these prediction models. Therefore, the influence of specific deterioration of a high pressure compressor (HPC) to jet engine performance parameters such as exhaust gas temperature (EGT) and specific fuel consumption (SFC) will be investigated. For this purpose, computational fluid dynamic (CFD) calculations of deteriorated HPC geometries are carried out and serve as a basis to scale the reference HPC performance characteristics to deteriorated ones. To evaluate the changes in performance parameters, a modular performance synthesis model is set up. In this model, the HPC map is exchanged with deteriorated ones. As a result, the influence of geometric deviations to the design intent can be determined, and the MRO companies are able to focus on the most relevant sections of the compressor blading.