Abstract:Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on the performance as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions. Quantitative results both indi… Show more
“…The depositions cause big roughness structures. 19–22 Figure 5.Examples of the blisk blade roughness of a small aircraft engine. The size of the measured area is 0.270 mm by 0.203 mm.…”
Section: Resultsmentioning
confidence: 99%
“…At the leading edge region, particles will only stick on the surface with this oil, because otherwise particles will be transported further downstream, because of the high shear stresses near the wall. 19 With lower shear stress rates further downstream on the blades, more and more deposition can build up resulting in higher values for the roughness height in all roughness parameters. Especially, in the first stage, a significant increase can be detected in the trailing edge region.…”
Section: Single-blade Roughnessmentioning
confidence: 98%
“…The dependency of the k s determination method leads to a higher sensitivity of this parameter for the anisotropy and direction of the roughness structures. Other investigations showed 19,20 that because of oil leakage from the bearing system of the engine, sticky liquid can enter the flow path and is transported along the blades because of the centrifugal force. At the leading edge region, particles will only stick on the surface with this oil, because otherwise particles will be transported further downstream, because of the high shear stresses near the wall.…”
Section: Single-blade Roughnessmentioning
confidence: 99%
“…The roughness structure shape is isotropically scattered with steep flanks and represents depositions. 17,19,20 The size and quantity of the depositions decrease through the compressor, and at the trailing edge region of the last stage almost no depositions are detectable.…”
Section: Single-blade Roughnessmentioning
confidence: 99%
“…The depositions cause big roughness structures. [19][20][21][22] On the pressure side, an overall mean of Ra ¼ 0.6 mm (Rq ¼ 0.76 mm, Rz ¼ 3.47 mm, k s ¼ 1.17 mm) is determined. Also, slight variations along the chord and the span are detectable, but these variations are smaller compared to the suction side roughness.…”
Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.
“…The depositions cause big roughness structures. 19–22 Figure 5.Examples of the blisk blade roughness of a small aircraft engine. The size of the measured area is 0.270 mm by 0.203 mm.…”
Section: Resultsmentioning
confidence: 99%
“…At the leading edge region, particles will only stick on the surface with this oil, because otherwise particles will be transported further downstream, because of the high shear stresses near the wall. 19 With lower shear stress rates further downstream on the blades, more and more deposition can build up resulting in higher values for the roughness height in all roughness parameters. Especially, in the first stage, a significant increase can be detected in the trailing edge region.…”
Section: Single-blade Roughnessmentioning
confidence: 98%
“…The dependency of the k s determination method leads to a higher sensitivity of this parameter for the anisotropy and direction of the roughness structures. Other investigations showed 19,20 that because of oil leakage from the bearing system of the engine, sticky liquid can enter the flow path and is transported along the blades because of the centrifugal force. At the leading edge region, particles will only stick on the surface with this oil, because otherwise particles will be transported further downstream, because of the high shear stresses near the wall.…”
Section: Single-blade Roughnessmentioning
confidence: 99%
“…The roughness structure shape is isotropically scattered with steep flanks and represents depositions. 17,19,20 The size and quantity of the depositions decrease through the compressor, and at the trailing edge region of the last stage almost no depositions are detectable.…”
Section: Single-blade Roughnessmentioning
confidence: 99%
“…The depositions cause big roughness structures. [19][20][21][22] On the pressure side, an overall mean of Ra ¼ 0.6 mm (Rq ¼ 0.76 mm, Rz ¼ 3.47 mm, k s ¼ 1.17 mm) is determined. Also, slight variations along the chord and the span are detectable, but these variations are smaller compared to the suction side roughness.…”
Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.
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