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.

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.

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.

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.

Investigation on the Effect of Surface Wettability on a Two-Phase Flow in a Compressor Cascade

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Niklas Neupert ◽  
Janneck Christoph Harbeck ◽  
Franz Joos
Keyword(s):  
Mach Number ◽  
Gas Turbines ◽  
Two Phase Flow ◽  
Contact Angles ◽  
Surface Wettability ◽  
Phase Flow ◽  
Compressor Cascade ◽  
Two Phase ◽  
Hydrophobic Coatings ◽  
Transonic Compressor

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. Further deposited water leads to a higher sensitivity toward fouling due to an increased stickiness of the blades. Therefore, erosion resistant hydrophobic coatings are applied to the first stages of compressors. Although some patents claim the use of such coatings the aerodynamic impact of a different wettability is not regarded so far. This issue was addressed in the field of aerodynamic efficiency of wings in heavy rain showing higher penalty for hydrophobic coatings. In this study, the issue of a different blade surface wettability in a linear transonic compressor cascade is addressed. Different coatings are applied resulting in contact angles of 51–95 deg. The inflow Mach number was fixed at design inflow Mach number, and the inflow angle was varied over a broad range. The effect on the water film pattern is analyzed in terms of position of film breakup, rivulet width, and totally wetted surface. The performance of the cascade under two-phase flow was analyzed using laser Doppler anemometry/phase Doppler anemometry measurement technique in terms of loss coefficient based on wake momentum thickness and flow turning. It is shown that the wettability of the surface has significant effects on the film structure leading to a lower fraction of wetted surface with increasing contact angle. The influence on performance is limited to effects in the proximity of the surface and is dependent on operation point. While in design conditions hydrophilic coating show lower losses, the trend is vice-versa for off-design conditions. The data represent first experimental work on the influence of surface wettability in a droplet-laden flow supporting positive features for hydrophobic coatings in gas turbine compressors.

Investigation on the Effect of Surface Wettability on a Two-Phase Flow in a Compressor Cascade

2017 ◽  
Author(s):  
Niklas Neupert ◽  
Janneck Christoph Harbeck ◽  
Franz Joos
Keyword(s):  
Mach Number ◽  
Gas Turbines ◽  
Two Phase Flow ◽  
Contact Angles ◽  
Surface Wettability ◽  
Phase Flow ◽  
Compressor Cascade ◽  
Two Phase ◽  
Hydrophobic Coatings ◽  
Transonic Compressor

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. Further deposited water leads to a higher sensitivity towards fouling due to an increased stickiness of the blades. Therefore erosion resistant hydrophobic coatings are applied to the first stages of compressors. Although some patents claim the use of such coatings the aerodynamic impact of a different wettability is not regarded so far. This issue was addressed in the field of aerodynamic efficiency of wings in heavy rain showing higher penalty for hydrophobic coatings. In this study the issue of a different blade surface wettability in a linear transonic compressor cascade is addressed. Different coatings are applied resulting in contact angles of 51–95°. The inflow Mach number was fixed at design inflow Mach number and the inflow angle was varied over a broad range. The effect on the water film pattern is analyzed in terms of position of film breakup, rivulet width and totally wetted surface. The performance of the cascade under two-phase flow was analyzed using LDA/PDA measurement technique in terms of loss coefficient based on wake momentum thickness and flow turning. It is shown that the wettability of the surface has significant effects on the film structure leading to a lower fraction of wetted surface with increasing contact angle. The influence on performance is limited to effects in the proximity of the surface and is dependent on operation point. While in design conditions hydrophilic coating show lower losses the trend is vice-versa for off-design conditions. The data represent first experimental work on the influence of surface wettability in a droplet-laden flow supporting positive features for hydrophobic coatings in gas turbine compressors.

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 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.

Development and Application of Industrial Gas Turbines for Medium-Btu Gaseous Fuels

1986 ◽  
Vol 108 (1) ◽  
pp. 182-190 ◽  
Author(s):  
J. G. Meier ◽  
W. S. Y. Hung ◽  
V. M. Sood
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Point Of View ◽  
Combustion System ◽  
Successful Development ◽  
Gaseous Fuels ◽  
Sanitary Landfills ◽  
Industrial Gas Turbines ◽  
Alternate Fuels

This paper describes the successful development and application of industrial gas turbines using medium-Btu gaseous fuels, including those derived from biodegradation of organic matters found in sanitary landfills and liquid sewage. The effects on the gas turbine and its combustion system of burning these alternate fuels compared to burning high-Btu fuels, along with the gas turbine development required to use alternate fuels from the point of view of combustion process, control system, gas turbine durability, maintainability and safety, are discussed.

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.

scholarly journals The Application and Experience of HVOF Coatings in the Repair and Overhaul of Industrial Gas Turbines

1994 ◽  
Author(s):  
C. W. Smith ◽  
G. Naisbitt
Keyword(s):  
Gas Turbine ◽  
Thermal Spray ◽  
High Velocity ◽  
Gas Turbines ◽  
High Energy ◽  
Point Of View ◽  
High Wear Resistance ◽  
Carbide Coatings ◽  
Industrial Gas Turbines ◽  
Initial Source

High Velocity Oxy-Fuel thermal spray systems (HVOF), also known as High Velocity Combustion systems (HVC) are high energy thermal spray combustion processes, producing very hard, high density coatings. These coatings are used in areas where high wear resistance is of particular importance, with metal carbide coatings being typical in gas turbine applications. Gas turbines use hard face coatings in such areas where vibration is the initial source of the problem. The areas tend to be in the hot end of the gas turbines although certain areas of the cold end are also affected. To date the hard face coating that has been predominately applied in gas turbines particularly in the hot end, is the Praxair (Union Carbide) “D” gun coating. As a result to date, the “D” gun system has had a virtual monopoly with regards to the overhaul/repair of gas turbine components where hard face coating was required. However new HVOF systems have come on to the market Examples are: CDS, Plasma Technik; Diamond Jet, Metco; Top Gun, UPT U.K. (Miller); Jet Kote, Deloro Stellite; Gun. Metallisation and JP 5000, Hobart Tafa. As a result gas turbine overhaul bases are now in a position to offer a more competitve coating service, producing comparable, and in some cases superior, coatings to those produced by the “D” gun process. This paper covers, from the Rolls Wood Group point of view, the developments of the HVOF systems, where they appear to be today and how these systems, now allow overhaul bases to offer services not previously available and the ability to develop new coating applications.

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