scholarly journals Investigation of flow characteristics inside a dual bell nozzle with and without film cooling

2020 ◽  
Vol 99 ◽  
pp. 105741 ◽  
Author(s):  
Mayank Verma ◽  
Nitish Arya ◽  
Ashoke De
Keyword(s):  
Film Cooling ◽  
Flow Characteristics ◽  
Dual Bell

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

Active Control of Dual-Bell Nozzle Operation Mode Transition by Film Cooling and Mixture Ratio Variation

2020 ◽  
Vol 36 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Dirk Schneider ◽  
Ralf Stark ◽  
Chloé Génin ◽  
Michael Oschwald ◽  
Konstantin Kostyrkin
Keyword(s):  
Active Control ◽  
Film Cooling ◽  
Operation Mode ◽  
Mode Transition ◽  
Mixture Ratio ◽  
Ratio Variation ◽  
Dual Bell

Flow Characteristics and Aerodynamic Losses of Film-Cooling Jets With Compound Angle Orientations

1997 ◽  
Vol 119 (2) ◽  
pp. 310-319 ◽  
Author(s):  
Sang Woo Lee ◽  
Yong Beom Kim ◽  
Joon Sik Lee
Keyword(s):  
Film Cooling ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Orientation Angle ◽  
Surface Flow ◽  
Test Surface ◽  
Flow Measurements ◽  
Aerodynamic Loss ◽  
Flow Visualizations ◽  
Compound Angle

Oil-film flow visualizations and three-dimensional flow measurements using a five-hole probe have been conducted to investigate the flow characteristics and aerodynamic loss distributions of film-cooling jets with compound angle orientations. For a fixed inclination angle of the injection hole, measurements are performed at various orientation angles to the direction of the mainstream in the case of three velocity ratios of 0.5, 1.0, and 2.0. Flow visualizations for the velocity ratio of 2.0 show that the increase in the orientation angle furnishes better film coverage on the test surface, but gives rise to large flow disturbances in the mainstream. A near-wall flow model has been proposed based on the surface flow visualizations. It has also been found from the flow measurements that as the orientation angle increases, a pair of count-errotating vortices turn to a single strong one, and the aerodynamic loss field is closely related to the secondary flow. Even in the case of the velocity ratio of 2.0, aerodynamic loss is produced within the jet region when the orientation angle is large. Regardless of the velocity ratio, the mass-averaged aerodynamic loss increases with increasing orientation angle, the effect of which on aerodynamic loss is pronounced when the velocity ratio is large.

Investigations of improved cooling effectiveness for ramp film cooling with compound angle film cooling jets

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krishna Anand Vasu Devan Nair Girija Kumari ◽  
Parammasivam Kanjikoil Mahali
Keyword(s):  
Film Cooling ◽  
Flat Surface ◽  
Flow Characteristics ◽  
Test Surface ◽  
Cooling Effectiveness ◽  
Content Type ◽  
Film Cooling Effectiveness ◽  
Ramp Test ◽  
Cooling Hole ◽  
Compound Angle

Purpose This paper aims to investigate the film cooling effectiveness (FCE) and mixing flow characteristics of the flat surface ramp model integrated with a compound angled film cooling jet. Design/methodology/approach Three-dimensional numerical simulation is performed on a flat surface ramp model with Reynolds Averaged Navier-Stokes approach using a finite volume solver. The tested model has a fixed ramp angle of 24° and a ramp width of two times the diameter of the film cooling hole. The coolant air is injected at 30° along the freestream direction. Three different film hole compound angles oriented to freestream direction at 0°, 90° and 180° were investigated for their performance on-ramp film cooling. The tested blowing ratios (BRs) are in the range of 0.9–2.0. Findings The film hole oriented at a compound angle of 180° has improved the area-averaged FCE on the ramp test surface by 86.74% at a mid-BR of 1.4% and 318.75% at higher BRs of 2.0. The 180° film hole compound angle has also produced higher local and spanwise averaged FCE on the ramp test surface. Originality/value According to the authors’ knowledge, this study is the first of its kind to investigate the ramp film cooling with a compound angle film cooling hole. The improved ramp model with a 180° film hole compound angle can be effectively applied for the end-wall surfaces of gas turbine film cooling.

scholarly journals Influence of twisted tape insert on the coolant flow characteristics in swirled film cooling

2021 ◽  
pp. 259-259
Author(s):  
Vashista Ademane ◽  
Ravikiran Kadoli ◽  
Vijaykumar Hindasageri
Keyword(s):  
Film Cooling ◽  
Flow Characteristics ◽  
Coolant Flow ◽  
Twisted Tape ◽  
Pumping Power ◽  
Pressure Losses ◽  
Jet Trajectory ◽  
Swirl Intensity ◽  
Cooling Behavior ◽  
Coefficient Of Discharge

The Present paper discusses film cooling behavior through numerical simulation in the presence of a twisted tape insert inside the film hole. The twisted tape insert imparts a swirl to the coolant flow. Coolant swirl intensity is controlled by varying the pitch of the twisted tape resulting in swirl numbers (S) of 0.0289, 0.116 and 0.168. The film cooling performance is evaluated using area-averaged effectiveness and heat transfer coefficient for blowing ratios of 0.5, 1.0, 1.5 and 2.0. Results revealed a significant amount of improvement in averaged effectiveness with the addition of swirl. Coolant swirl predominantly modifies the jet trajectory resulting in a reduced jet penetration and increased lateral expansion. Further investigation on the effect of twisted tape thickness on the coolant distribution has been found to be negligible. Pressure losses occurring due to the insertion of twisted tape inside the film hole is evaluated through the coefficient of discharge which indicated the necessity of higher pumping power than the film cooling case with no-swirl.

Effect of Upstream Purge Slot on a Transonic Turbine Blade Passage: Part 1 — Aerodynamic Performance

2013 ◽  
Author(s):  
Dorian M. Blot ◽  
Arnab Roy ◽  
Srinath V. Ekkad ◽  
Wing Ng ◽  
Andrew S. Lohaus ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
Incidence Angle ◽  
Flow Characteristics ◽  
Experimental Results ◽  
Backward Facing Step ◽  
Film Cooling Effectiveness

In this paper, detailed experimental results of total pressure loss and secondary flow field are presented for a high turning (127°) airfoil passage in presence of an upstream purge slot (with and without coolant injection). The experiments were performed at Virginia Tech’s quasi 2D linear turbine cascade operating at transonic conditions. Measurements were made at design exit Mach number 0.88 and design incidence angle. The selected coolant to mainstream mass flow ratio (MFR) was set at 1.0%. In order to match engine representative inlet/exit blade loading, a diverging endwall was utilized where the span increased from the inlet to the exit at a 13 degree angle. A 5-hole probe traverse was used to measure exit total pressure. Pressure loss coefficients were calculated both along pitchwise and spanwise directions at 0.1 axial chord downstream of the blade trailing edge. CFD studies were conducted to compliment the experimental results. The backward facing step present with the upstream slot affects the approaching boundary layer and influences the passage horse-shoe vortex strength. The addition of coolant from the purge slot further increased the aerodynamic losses. However, the backward facing step of the upstream slot seems to be the predominant factor in affecting pressure losses when compared to with or without blowing cases. These results provide further understanding of the passage secondary flow characteristics and aid towards improved design of endwall passages. The heat transfer experiments, designed to find the heat transfer coefficient and the film cooling effectiveness are described in detail in part II of this paper [1].

Parametric study of supersonic film cooling in dual bell nozzle for an experimental air–kerosene engine

2018 ◽  
Vol 78 ◽  
pp. 364-376 ◽  
Author(s):  
Siba Prasad Choudhury ◽  
Abhilash Suryan ◽  
J.C. Pisharady ◽  
A. Jayashree ◽  
Khalid Rashid
Keyword(s):  
Parametric Study ◽  
Film Cooling ◽  
Dual Bell

Effect of Hole Pitch Ratio and Compound Angle on the Thermal Flow Fields of Double-Jet Film Cooling Hole

2014 ◽  
Author(s):  
Moon-Young Cho ◽  
Hyeon-Seok Seo ◽  
Youn-Jea Kim
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Turbine Blades ◽  
Flow Characteristics ◽  
Thermal Flow ◽  
Film Cooling Effectiveness ◽  
Gas Turbine Blades ◽  
Ansys Cfx ◽  
Cooling Hole ◽  
Pitch Distance

In this study, the effect of a row of double-jet film-cooling hole configurations on the thermal-flow characteristics of gas turbine blades was examined. To investigate the effect of the interference of anti-kidney vortices, the ratios of the pitch distance and hole diameter (P/d=5, 6.25, 8.333) were considered with two different compound angles (λ=0°, 4°). The film cooling performance and the generated losses were studied. Then, the relevant mechanisms were identified and explained. A numerical study was performed using ANSYS CFX 14.5 with the shear stress transport (SST) turbulent model. The blowing ratio was kept at a constant value of M=1.5. The film cooling effectiveness and temperature distribution are graphically depicted with various geometrical configurations.

Practical Slot Configurations for Turbine Film Cooling Applications

2009 ◽  
Author(s):  
Joshua E. Bruce-Black ◽  
Frederick T. Davidson ◽  
David G. Bogard ◽  
David R. Johns
Keyword(s):  
Film Cooling ◽  
Flow Characteristics ◽  
Suction Side ◽  
Operating Conditions ◽  
Coolant Flow ◽  
Film Cooling Effectiveness ◽  
Diffusion Technique ◽  
Turbine Vane ◽  
Structural Weakness ◽  
Turbine Component

Turbine component film cooling is most effective when using a continuous slot to introduce coolant to the surface. However, this is not practical due to the structural weakness that would be inherent with a continuous slot. In this study, several slot-like designs are investigated to establish the film cooling effectiveness. These slot configurations extended only a partial distance through the simulated turbine vane wall, and were fed with impinging cylindrical holes. The configurations were studied on the suction side of a scaled-up turbine vane. In this study varying slot widths, discrete and continuous slots, and diffusing the coolant flow within the slot prior to it being emitted onto the surface of the vane were investigated. Rows of discrete round and shaped holes were also tested for comparison with the slots. The study of varying slot geometries showed that decreasing the width of the slots led to a substantial increase in adiabatic effectiveness. An internal coolant diffusion technique showed promise by maintaining performance levels while potentially providing a design configuration that more readily meets structural demands in real world operating conditions. The coolant flow characteristics were also studied through the use of thermal profiles measurements. These thermal profiles showed significant mainstream ingestion on the top surface of the slot prior to the coolant emitting onto the surface of the vane.

Experimental Study on Film Cooling Flow Characteristics of Turbine Stator Blade at Different Setting Angles

2012 ◽  
Vol 614-615 ◽  
pp. 592-595
Author(s):  
Ling Zhang ◽  
Hai Rui Dong ◽  
Guo Liang Wen
Keyword(s):  
Film Cooling ◽  
Effective Means ◽  
Turbine Blades ◽  
Flow Characteristics ◽  
Suction Side ◽  
Pressure Side ◽  
Blowing Ratio ◽  
Turbine Stator ◽  
Setting Angle ◽  
Stator Blade

The technology of film cooling is one of the most effective means of protecting the turbine blades. In this paper, flow structures of the turbine stator blade with six hole-rows at different blowing ratio（M=0.5, 1.0 and 1.5）and setting angles（β=40°, 50°, 60°, 70°, 80° and 90°） was measured by PIV in piston flow type of low-speed wind tunnel laboratory. Velocity was analyzed. Results show that: velocity gradient of suction side was much higher than pressure side and increased with setting angle reduction; Adherence of film is influenced by setting angle and blowing ratio, when M=1.0 and β=70° anchorage dependent is best and suction side is greater than pressure side.

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