An Experimentally Derived Model to Predict the Water Film in a Compressor Cascade With Droplet Laden Flow

2017 ◽  
Author(s):  
Niklas Neupert ◽  
Janneck Christoph Harbeck ◽  
Franz Joos
Keyword(s):  
Film Thickness ◽  
Gas Turbines ◽  
Water Film ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
System A ◽  
Quantitative Image ◽  
Industrial Gas Turbines ◽  
Measured Flow

In recent years overspray fogging has become a powerful means for power augmentation of industrial gas turbines. Despite the positive thermodynamic effect on the cycle droplets entering the compressor increase the risk of water droplet erosion and deposition of water on the blades leading to an increase of required torque and profile loss. Due to this detailed information about the structure and the amount of water on the surface is key for compressor performance. Experiments were conducted with a droplet laden flow in a transonic compressor cascade focusing on the film formed by the deposited water. Two approaches were taken. In the first approach the film thickness on the blade was directly measured using white light interferometry. Due to significant distortion of the flow caused by the measurement system a transfer of the measured film thickness to the undisturbed case is not possible. Therefore, a film model is adapted to describe the film flow in terms of height averaged film parameters. In the second approach experiments were conducted in an undisturbed cascade setup and the water film pattern was measured using a non-intrusive quantitative image processing tool. Utilizing the measured flow pattern in combination with findings from literature the rivulet flow structure is resolved. From continuity of the water flow a film thickness is derived showing good agreement with the previously calculated results. Using both approaches a 3D reconstruction of the water film pattern is created giving first experimental results of the film forming on stationary compressor blades under overspray fogging conditions.

An Experimentally Derived Model to Predict the Water Film in a Compressor Cascade With Droplet Laden Flow

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Niklas Neupert ◽  
Janneck Christoph Harbeck ◽  
Franz Joos
Keyword(s):  
Film Thickness ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Water Film ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
System A ◽  
Industrial Gas Turbines ◽  
Measured Flow

In recent years, overspray fogging has become a powerful means for power augmentation of industrial gas turbines. Despite the positive thermodynamic effect on the cycle, droplets entering the compressor increase the risk of water droplet erosion and deposition of water on the blades leading to an increase of required torque and profile loss. Due to this, detailed information about the structure and the amount of water on the surface is key for compressor performance. Experiments were conducted with a droplet laden flow in a transonic compressor cascade focusing on the film formed by the deposited water. Two approaches were taken. In the first approach, the film thickness on the blade was directly measured using white light interferometry. Due to significant distortion of the flow caused by the measurement system, a transfer of the measured film thickness to the undisturbed case is not possible. Therefore, a film model is adapted to describe the film flow in terms of height averaged film parameters. In the second approach, experiments were conducted in an undisturbed cascade setup and the water film pattern was measured using a nonintrusive quantitative image processing tool. Utilizing the measured flow pattern in combination with findings from the literature, the rivulet flow structure is resolved. From continuity of the water flow, a film thickness is derived showing good agreement with the previously calculated results. Using both approaches, a three-dimensional (3D) reconstruction of the water film pattern is created giving first experimental results of the film forming on stationary compressor blades under overspray fogging conditions.

Experimental Investigation on Droplet Behavior in a Transonic Compressor Cascade

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Niklas Neupert ◽  
Birger Ober ◽  
Franz Joos
Keyword(s):  
Experimental Investigation ◽  
Gas Turbines ◽  
Surface Film ◽  
Flow Channel ◽  
Point Of View ◽  
Compressor Cascade ◽  
Two Phase ◽  
Transonic Compressor ◽  
Droplet Behavior ◽  
Industrial Gas Turbines

In recent years, overspray fogging has become a powerful means for power augmentation of industrial gas turbines (GT). Most of the studies concerning this topic focus on the problem from a thermodynamic point of view. Only a few studies, however, were undertaken to investigate the droplet behavior in the flow channel of a compressor. In this paper, results of experimental investigation of a water laden flow through a transonic compressor cascade are presented. A finely dispersed spray was used in the measurements (D10 < 10 μm). Results of the droplet behavior are shown in terms of shadowgraphy images and images of the blade surface film pattern. The angle of attack, the incoming velocity, and the water load were varied. The qualitative observations are related to laser Doppler and phase Doppler anemometer (LDA/PDA) data taken in the flow channel and at the outlet of the cascade. The data represent a base for numerical and mean line models of two-phase compressor flow.

scholarly journals Industrial Gas Turbine Performance: Compressor Fouling and On-Line Washing

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Uyioghosa Igie ◽  
Pericles Pilidis ◽  
Dimitrios Fouflias ◽  
Kenneth Ramsden ◽  
Panagiotis Laskaridis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Operating Conditions ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Turbine Performance ◽  
Industrial Gas Turbines ◽  
On Line ◽  
The Impact

Industrial gas turbines are susceptible to compressor fouling, which is the deposition and accretion of airborne particles or contaminants on the compressor blades. This paper demonstrates the blade aerodynamic effects of fouling through experimental compressor cascade tests and the accompanied engine performance degradation using turbomatch, an in-house gas turbine performance software. Similarly, on-line compressor washing is implemented taking into account typical operating conditions comparable with industry high pressure washing. The fouling study shows the changes in the individual stage maps of the compressor in this condition, the impact of degradation during part-load, influence of control variables, and the identification of key parameters to ascertain fouling levels. Applying demineralized water for 10 min, with a liquid-to-air ratio of 0.2%, the aerodynamic performance of the blade is shown to improve, however most of the cleaning effect occurred in the first 5 min. The most effectively washed part of the blade was the pressure side, in which most of the particles deposited during the accelerated fouling. The simulation of fouled and washed engine conditions indicates 30% recovery of the lost power due to washing.

Blade Faults Diagnosis in Power Generation Gas Turbines

2017 ◽  
Author(s):  
Meng Hee Lim ◽  
Salman Leong ◽  
Kar Hoou Hui
Keyword(s):  
Power Generation ◽  
Statistical Analysis ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Vibration Signal ◽  
Health Condition ◽  
Baseline Data ◽  
Compressor Blades ◽  
Industrial Gas Turbines

This paper presents a case study in managing the dilemma of whether to resume or stop the operation of a power generation gas turbine with suspected blade faults. Vibration analysis is undertaken on the vibration signal of the gas turbine, to obtain an insight into the health condition of the blades before any decision is made on the operation of the machine. Statistical analysis is applied to study the characteristics of the highly unstable blade pass frequency (BPF) of the gas turbine and to establish the baseline data used for blade fault assessment and diagnosis. Based on the excessive increase observed on specific BPF amplitudes in comparison to the statistical baseline data, rubbing at the compressor blade is suspected. An immediate overhaul is therefore warranted, and the results from the inspection of the machine confirm the occurrence of severe rubbing at the compressor blades and labyrinth glands of the gas turbine. In conclusion, statistical analysis of BPF amplitude is found to be a viable tool for blade fault diagnosis in industrial gas turbines.

Blade Forced Response Prediction for Industrial Gas Turbines: Part 1 — Methodologies

2003 ◽  
Author(s):  
Stuart Moffatt ◽  
Li He
Keyword(s):  
Frequency Domain ◽  
Gas Turbines ◽  
Stokes Equations ◽  
Physical Space ◽  
Response Prediction ◽  
Forced Response ◽  
Navier Stokes ◽  
Loosely Coupled ◽  
Transonic Compressor ◽  
Industrial Gas Turbines

Forming the first part of a two-part paper, the methodology of an efficient frequency-domain approach for predicting the forced response of turbomachinery blades is presented. The capability and computational efficiency of the method are demonstrated in Part Two with a three-stage transonic compressor case. Interaction between fluid and structure is dealt with in a loosely coupled manner, based on the assumption of linear aerodynamic damping and negligible frequency shift. The Finite Element (FE) package ANSYS is used to provide the mode shape and natural frequency of a particular mode, which is interpolated onto the CFD mesh. The linearised unsteady Navier-Stokes equations are solved in the frequency domain using a single-passage approach to provide aerodynamic excitation and damping forces. Two methods of obtaining the single degree-of-freedom forced response solution are demonstrated: the Modal Reduction Technique, solving the modal forced response equation in modal space; and a new Energy Method, an alternative method allowing calculations to be performed directly and simply in physical space. Both methods are demonstrated in a preliminary case study of the NASA R67 transonic fan blade with excitation of the 1st torsion mode due to a hypothetical inlet distortion.

An analytical approach to predicting particle deposit by fouling in the axial compressor of the industrial gas turbine

2005 ◽  
Vol 219 (3) ◽  
pp. 203-212 ◽  
Author(s):  
T W Song ◽  
J L Sohn ◽  
T S Kim ◽  
J H Kim ◽  
S T Ro
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Axial Compressor ◽  
Design Parameters ◽  
Compressor Blades ◽  
Particle Distributions ◽  
Industrial Gas Turbines ◽  
Industrial Gas Turbine ◽  
Physical Phenomena

The gas turbine performance deteriorates with increased operating hours. Fouling in the axial compressor is an important factor for the performance degradation of gas turbines. Airborne particles entering the compressor with the air adhere to the blade surface and result in the change of the blade shape, which directly influences the compressor performance. It is difficult to exactly understand the mechanism of compressor fouling because of its slow growth and different length scales of compressor blades. In this study, an analytical method to predict the particle motion in the axial compressor and the characteristics of particle deposition onto blade is proposed as an approach to investigating physical phenomena of fouling in the axial compressor of industrial gas turbines. Calculated results using the proposed method and comparison with measured data demonstrate the feasibility of the model. It was also found that design parameters of the axial compressor such as chord length, solidity, and number of stages are closely related to the fouling phenomena. Likewise, the particle size and patterns of particle distributions are also important factors related to fouling phenomena in the axial compressor.

Experimental Investigation on Droplet Behaviour in a Transonic Compressor Cascade

2014 ◽  
Author(s):  
Niklas Neupert ◽  
Birger Ober ◽  
Franz Joos
Keyword(s):  
Experimental Investigation ◽  
Flow Pattern ◽  
Gas Turbines ◽  
Surface Film ◽  
Flow Channel ◽  
Point Of View ◽  
Compressor Cascade ◽  
Two Phase ◽  
Transonic Compressor ◽  
Droplet Behavior

In recent years overspray fogging has become a powerful means for power augmentation of industrial gas turbines. Most of the studies concerning this topic focus on the problem from a thermodynamic point of view as summarized by Eisfeld and Joos [1]. Only a few studies, however, were undertaken to investigate the droplet behavior in the flow channel of a compressor. Eisfeld and Joos [2] and Ober [3] revealed qualitative results showing a large variety of two-phase phenomena present. In this paper results of experimental investigation of a water laden flow through a compressor cascade are presented. A finely dispersed spray was used in the measurements (D10 < 10μm). Results of the droplet behavior in a transonic compressor cascade are shown in terms of shadowgraphy images and images of the blade surface film pattern. The angle of attack, the incoming velocity and the water load were varied to estimate the influence of these parameters on the flow pattern. The qualitative observations of the flow pattern are related to LDA/PDA data of the flow channel and at the outlet of the cascade. The data represents a base for numerical and mean line models of two phase compressor flow concerning droplet-wall interactions as well as flow induced breakup.

scholarly journals Investigation of Wash Fluid Preheating on the Effectiveness of Online Compressor Washing in Industrial Gas Turbines

2020 ◽  
Author(s):  
Roupa Agbadede ◽  
Biweri Kainga
Keyword(s):  
Gas Turbines ◽  
Pressure Loss ◽  
Total Pressure ◽  
Loss Coefficient ◽  
Total Pressure Loss ◽  
Compressor Cascade ◽  
Flow Angle ◽  
Pressure Loss Coefficient ◽  
Industrial Gas Turbines ◽  
Total Pressure Loss Coefficient

Abstract This study presents an investigation of wash fluid preheating on the effectiveness of online compressor washing in industrial gas turbines. Crude oil was uniformly applied on the compressor cascade blades surfaces using a roller brush, and carborundum particles were ingested into the tunnel to create accelerated fouled blades. Demineralized water was preheated to 500C using the heat coil provided in the tank. When fouled blades washed with preheated demineralized and the one without preheating were compared, it was observed that there was little or no difference in terms of total pressure loss coefficient and exit flow angle. However, when the fouled and washed cases were compared, there was a significant different in total pressure loss coefficient and exit flow angle.

Experimental Investigation of the Forcing Function and Forced Pitching Blade Oscillations of an Annular Compressor Cascade in Transonic Flow

2010 ◽  
Author(s):  
Joachim Belz ◽  
Holger Hennings ◽  
Gerhard Kahl
Keyword(s):  
Transonic Flow ◽  
Turbine Blades ◽  
Rotor Blades ◽  
Test Facility ◽  
Experimental Investigations ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
Forcing Function ◽  
Annular Cascade

The interaction between rotor blades and non-rotating stator blades is the most significant blade excitation mechanism in turbomachines. It is well documented in various numerical and experimental investigations for turbine cascades. Like turbine blades, also compressor blades are excited as well by potential fields of the following stator, the downstream flowfield of the stator of the previous stage or struts and incoming flow distortions. In this paper, experimental investigations of the excitation of a transonic compressor cascade due to gust generating struts upstream are presented. The experiments were performed in the test facility of non-rotating annular cascades at EPFL using a compressor cascade, which consists of 20 blades (NACA3506 profile) mounted on elastic spring suspensions for torsional motions at the midchord. For the non-rotating annular cascade, relative flow conditions similar to those present in a rotating cascade are generating by swirling the flow in front of the test test section. The struts are rotating in order to create a periodic excitation upstream of the cascade. The so generated pressure distribution on the cascade’s profiles as well as the measured vibration response of the blades are presented and compared for a pure subsonic and a transonic flow case.

scholarly journals Evaporation Modeling of Water Droplets in a Transonic Compressor Cascade under Fogging Conditions

2020 ◽  
Vol 5 (1) ◽  
pp. 5
Author(s):  
Adrian Seck ◽  
Silvio Geist ◽  
Janneck Harbeck ◽  
Bernhard Weigand ◽  
Franz Joos
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Measured Parameter ◽  
Water Droplets ◽  
Compressor Cascade ◽  
Transonic Compressor ◽  
Major Significance ◽  
Power Outputs ◽  
Influential Parameters ◽  
Inflow Conditions

High-fogging is widely used to rapidly increase the power outputs of stationary gas turbines. Therefore, water droplets are injected into the inflow air, and a considerable number enter the compressor. Within this paper, the primary process of droplet evaporation is investigated closely. A short discussion about the influential parameters ascribes a major significance to the slip velocity between ambient gas flow and droplets. Hence, experimental results from a transonic compressor cascade are shown to evaluate the conditions in real high-fogging applications. The measured parameter range is used for direct numerical simulations to extract evaporation rates depending on inflow conditions and relative humidity of the air flow. Finally, an applicable correlation for the Sherwood number in the form of S h ( R e 1 / 2 S c 1 / 3 ) is suggested.

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