scholarly journals Reduction in Flow Parameter Resulting From Volcanic Ash Deposition in Engine Representative Cooling Passages

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Sebastien Wylie ◽  
Alexander Bucknell ◽  
Peter Forsyth ◽  
Matthew McGilvray ◽  
David R. H. Gillespie
Keyword(s):  
Film Cooling ◽  
Volcanic Ash ◽  
Flow Parameter ◽  
Cooling System ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Metal Temperature ◽  
Internal Cooling ◽  
Cooling Hole ◽  
Cooling Passage

Internal cooling passages of turbine blades have long been at risk to blockage through the deposition of sand and dust during fleet service life. The ingestion of high volumes of volcanic ash (VA) therefore poses a real risk to engine operability. An additional difficulty is that the cooling system is frequently impossible to inspect in order to assess the level of deposition. This paper reports results from experiments carried out at typical high pressure (HP) turbine blade metal temperatures (1163 K to 1293 K) and coolant inlet temperatures (800 K to 900 K) in engine scale models of a turbine cooling passage with film-cooling offtakes. Volcanic ash samples from the 2010 Eyjafjallajökull eruption were used for the majority of the experiments conducted. A further ash sample from the Chaiten eruption allowed the effect of changing ash chemical composition to be investigated. The experimental rig allows the metered delivery of volcanic ash through the coolant system at the start of a test. The key metric indicating blockage is the flow parameter (FP), which can be determined over a range of pressure ratios (1.01–1.06) before and after each experiment, with visual inspection used to determine the deposition location. Results from the experiments have determined the threshold metal temperature at which blockage occurs for the ash samples available, and characterize the reduction of flow parameter with changing particle size distribution, blade metal temperature, ash sample composition, film-cooling hole configuration and pressure ratio across the holes. There is qualitative evidence that hole geometry can be manipulated to decrease the likelihood of blockage. A discrete phase computational fluid dynamics (CFD) model implemented in Fluent has allowed the trajectory of the ash particles within the coolant passages to be modeled, and these results are used to help explain the behavior observed.

scholarly journals Reduction in Flow Parameter Resulting From Volcanic Ash Deposition in Engine Representative Cooling Passages

2016 ◽  
Author(s):  
Sebastien Wylie ◽  
Alexander Bucknell ◽  
Peter Forsyth ◽  
Matthew McGilvray ◽  
David R. H. Gillespie
Keyword(s):  
Film Cooling ◽  
Volcanic Ash ◽  
Flow Parameter ◽  
Cooling System ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Metal Temperature ◽  
Internal Cooling ◽  
Cooling Hole ◽  
Cooling Passage

Internal cooling passages of turbine blades have long been at risk to blockage through the deposition of sand and dust during fleet service life. The ingestion of high volumes of volcanic ash therefore poses a real risk to engine operability. An additional difficulty is that the cooling system is frequently impossible to inspect in order to assess the level of deposition. This paper reports results from experiments carried out at typical HP turbine blade metal temperatures (1163K to 1293K) and coolant inlet temperatures (800K to 900K) in engine scale models of a turbine cooling passage with film-cooling offtakes. Volcanic ash samples from the 2010 Eyjafjallajökull eruption were used for the majority of the experiments conducted. A further ash sample from the Chaiten eruption allowed the effect of changing ash chemical composition to be investigated. The experimental rig allows the metered delivery of volcanic ash through the coolant system at the start of a test. The key metric indicating blockage is the flow parameter which can be determined over a range of pressure ratios (1.01–1.06) before and after each experiment, with visual inspection used to determine the deposition location. Results from the experiments have determined the threshold metal temperature at which blockage occurs for the ash samples available, and characterise the reduction of flow parameter with changing particle size distribution, blade metal temperature, ash sample composition, film-cooling hole configuration and pressure ratio across the holes. There is qualitative evidence that hole geometry can be manipulated to decrease the likelihood of blockage. A discrete phase CFD model implemented in Fluent has allowed the trajectory of the ash particles within the coolant passages to be modelled, and these results are used to help explain the behaviour observed.

Combined Experimental and CFD Study of a HP Blade Multi-Pass Cooling System

2009 ◽  
Author(s):  
D. Jackson ◽  
P. Ireland ◽  
B. Cheong
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Cooling System ◽  
Detailed Comparison ◽  
Bulk Temperature ◽  
Internal Cooling ◽  
3 Dimensional ◽  
Turbine Cooling ◽  
Cooling Hole ◽  
The Difference

Progress in the computing power available for CFD predictions now means that full geometry, 3 dimensional predictions are now routinely used in internal cooling system design. This paper reports recent work at Rolls-Royce which has compared the flow and htc predictions in a modern HP turbine cooling system to experiments. The triple pass cooling system includes film cooling vents and inclined ribs. The high resolution heat transfer experiments show that different cooling performance features are predicted with different levels of fidelity by the CFD. The research also revealed the sensitivity of the prediction to accurate modelling of the film cooling hole discharge coefficients and a detailed comparison of the authors’ computer predictions to data available in the literature is reported. Mixed bulk temperature is frequently used in the determination of heat transfer coefficient from experimental data. The current CFD data is used to compare the mixed bulk temperature to the duct centreline temperature. The latter is measured experimentally and the effect of the difference between mixed bulk and centreline temperature is considered in detail.

Development of the Advanced Closed-Cycle Gas Turbine System

2001 ◽  
Author(s):  
Miki Koyama ◽  
Toshio Mimaki
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Early Stage ◽  
Turbine Blades ◽  
Thermal Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Turbine Inlet Temperature ◽  
Turbine Blade Cooling ◽  
Turbine Inlet

This aims to put the fruits of the R&D; “The Hydrogen Combustion Turbine” in WE-NET Phase I Program(1993-1998) to practical use at an early stage. The topping regenerating cycle was selected as the optimum cycle, with energy efficiency expected to be more than 60%(HHV) under the conditions of the turbine inlet temperature of 1973K(1700°C) and the pressure of 4.8MPa,in it. • As the turbine inlet temperature and pressure increase, issues to be resolved include the amount of NOx emissions and the durability of super alloys for turbine blades under such thermal conditions. In this respect, the development of the highly efficient methane-oxygen combustion technology, the turbine blade cooling technology, and the ultrahigh-temperature materials including thermal barrier coatings is being carried out. • In 1999, the results made it clear that there are little error among the three analytic programs used to verify the system efficiency, it was verified that the burning rate was going to arrive at over 98% from the methane-oxygen combustion test (under the atmospheric pressure). And the type of vane “Film cooling plus recycle type with internal cooling system” was selected as the most suitable vane.

Modeling of Film Cooling—Part II: Model for Use in Three-Dimensional Computational Fluid Dynamics

2006 ◽  
Vol 129 (2) ◽  
pp. 221-231 ◽  
Author(s):  
André Burdet ◽  
Reza S. Abhari ◽  
Martin G. Rose
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Film Cooling ◽  
Cooling System ◽  
Turbine Blades ◽  
Hybrid Approach ◽  
Processing Unit ◽  
Central Processing ◽  
Cooling Hole ◽  
Cooling Model

Computational fluid dynamics (CFD) has recently been used for the simulation of the aerothermodynamics of film cooling. The direct calculation of a single cooling hole requires substantial computational resources. A parametric study, for the optimization of the cooling system in real engines, is much too time consuming due to the large number of grid nodes required to cover all injection holes and plenum chambers. For these reasons, a hybrid approach is proposed, based on the modeling of the near film-cooling hole flow, tuned using experimental data, while computing directly the flow field in the blade-to-blade passage. A new injection film-cooling model is established, which can be embedded in a CFD code, to lower the central processing unit (CPU) cost and to reduce the simulation turnover time. The goal is to be able to simulate film-cooled turbine blades without having to explicitly mesh inside the holes and the plenum chamber. The stability, low CPU overhead level (1%) and accuracy of the proposed CFD-embedded film-cooling model are demonstrated in the ETHZ steady film-cooled flat-plate experiment presented in Part I (Bernsdorf, Rose, and Abhari, 2006, ASME J. Turbomach., 128, pp. 141–149) of this two-part paper. The prediction of film-cooling effectiveness using the CFD-embedded model is evaluated.

Modeling of Film Cooling: Part II — Model for Use in 3D CFD

2005 ◽  
Author(s):  
Andre´ Burdet ◽  
Reza S. Abhari ◽  
Martin G. Rose
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Turbine Blades ◽  
Hybrid Approach ◽  
Turnover Time ◽  
Processing Unit ◽  
Film Cooling Effectiveness ◽  
Central Processing ◽  
Cooling Hole ◽  
Cooling Model

Computational Fluid Dynamics (CFD) has been used recently for the simulation of the aerothermodynamics of film cooling. The direct calculation of a single cooling hole requires substantial computational resources. A parametric study, for the optimization of the cooling system in real engines, is much too time consuming due to the large number of grid nodes required to cover all injection holes and plenum chambers. For these reasons a hybrid approach is proposed, based on the modeling of the near film-cooling hole flow, tuned using experimental data, while computing directly the flow field in the blade-to-blade passage. A new injection film-cooling model is established, which can be embedded in a CFD code, to lower the Central Processing Unit (CPU) costs and reduce the simulation turnover time. The goal is to be able to simulate film-cooled turbine blades without having to explicitly mesh the holes with the plenum chamber. The stability, low CPU overhead level (1%) and accuracy of the proposed CFD-embedded film-cooling model, are demonstrated in the ETHZ steady film-cooled flat plate experiment [5] presented in Part I of this two-part paper. The prediction of film-cooling effectiveness using the CFD-embedded model is evaluated.

Film Cooling Discharge Coefficient Measurements in a Turbulated Passage With Internal Crossflow

2001 ◽  
Vol 123 (4) ◽  
pp. 774-780 ◽  
Author(s):  
Ronald S. Bunker ◽  
Jeremy C. Bailey
Keyword(s):  
Film Cooling ◽  
Discharge Coefficient ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Substantial Effect ◽  
Internal Cooling ◽  
Gas Turbine Blades ◽  
Discharge Coefficients ◽  
Cooling Enhancement

Gas turbine blades utilize internal geometry such as turbulator ribs for improved cooling. In some designs it may be desirable to benefit from the internal cooling enhancement of ribs as well as external film cooling. An experimental study has been performed to investigate the effect of turbulator rib placement on film hole discharge coefficient. In the study, a square passage having a hydraulic diameter of 1.27 cm is used to feed a single angled film jet. The film hole angle to the surface is 30 deg and the hole length-to-diameter ratio is 4. Turbulators were placed in one of three positions: upstream of film hole inlet, downstream of film hole inlet, and with the film hole inlet centered between turbulators. For each case 90 deg turbulators with a passage blockage of 15 percent and a pitch to height ratio of 10 were used. Tests were run varying film hole-to-crossflow orientation as 30, 90, and 180 deg, pressure ratio from 1.02 to 1.8, and channel crossflow velocity from Mach 0 to 0.3. Film hole flow is captured in a static plenum with no external crossflow. Experimental results of film discharge coefficients for the turbulated cases and for a baseline smooth passage are presented. Alignment of the film hole entry with respect to the turbulator is shown to have a substantial effect on the resulting discharge coefficients. Depending on the relative alignment and flow direction discharge coefficients can be increased or decreased 5–20 percent from the nonturbulated case, and in the worst instance experience a decrease of as much as 50 percent.

Film Cooling Discharge Coefficient Measurments in a Turbulated Passage With Internal Cross Flow

2001 ◽  
Author(s):  
Ronald S. Bunker ◽  
Jeremy C. Bailey
Keyword(s):  
Film Cooling ◽  
Discharge Coefficient ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Cross Flow ◽  
Substantial Effect ◽  
Internal Cooling ◽  
Discharge Coefficients ◽  
Cooling Enhancement

Gas turbine blades utilize internal geometry such as turbulator ribs for improved cooling. In some designs it may be desirable to benefit from the internal cooling enhancement of ribs as well as external film cooling. An experimental study has been performed to investigate the effect of turbulator rib placement on film hole discharge coefficient. In the study a square passage having a hydraulic diameter of 1.27 cm is used to feed a single angled film jet. The film hole angle to the surface is 30° and the hole length-to-diameter ratio is 4. Turbulators were placed in one of three positions: upstream of film hole inlet, downstream of film hole inlet, and with the film hole inlet centered between turbulators. For each case 90° turbulators with a passage blockage of 15% and a pitch to height ratio of 10 were used. Tests were run varying film hole-to-cross flow orientation as 30°, 90°, and 180°, pressure ratio from 1.02 to 1.8, and channel cross flow velocity from Mach 0 to 0.3. Film hole flow is captured in a static plenum with no external cross flow. Experimental results of film discharge coefficients for the turbulated cases and for a baseline smooth passage are presented. Alignment of the film hole entry with respect to the turbulator is shown to have a substantial effect on the resulting discharge coefficients. Depending on the relative alignment and flow direction, discharge coefficients can be increased or decreased 5 to 20% from the non-turbulated case, and in the worst instance experience a decrease of as much as 50%.

scholarly journals Internal Cooling Passage Heat Transfer Near the Entrance to a Film Cooling Hole: Experimental and Computational Results

1992 ◽  
Author(s):  
A. R. Byerley ◽  
T. V. Jones ◽  
P. T. Ireland
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Large Scale ◽  
Vortex Pair ◽  
Turbulent Channel Flow ◽  
Internal Cooling ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Cooling Hole ◽  
Cooling Passage

Detailed heat transfer measurements were made near the entrance to a single film cooling hole using a transient liquid crystal technique in a large scale (100X) model. The hole inclination angle and flow extraction rate were varied across a range representative of actual engine conditions. Local values of heat transfer were found to exceed 6 times the levels associated with fully developed, turbulent channel flow. The region of maximum heat transfer enhancement occurred downstream of the hole entrance. Computational and experimental flow diagnostics were performed to investigate the mechanisms responsible for the observed heat transfer distributions. The removal of the upstream boundary layer and the downwash created by a vortex pair were found to be important phenomena.

scholarly journals Influence of internal parallel and v-shaped ribs on the discharge coefficient of a cylindrical film cooling hole

2011 ◽  
Vol 225 (7) ◽  
pp. 985-994 ◽  
Author(s):  
C Heneka ◽  
A Schulz ◽  
H-J Bauer
Keyword(s):  
Mach Number ◽  
Cross Section ◽  
Film Cooling ◽  
Rectangular Cross Section ◽  
Internal Cooling ◽  
Cooling Hole ◽  
Rib Arrangement ◽  
Straight Flow ◽  
Cooling Passage ◽  
Internal Cooling Passage

An experimental study has been conducted to investigate the discharge behaviour of cylindrical film cooling holes with the main focus on the effects of rib arrangement and crossflow velocity inside the internal cooling passage of a gas turbine blade. Two straight flow channels of rectangular cross-section simulate the crossflow situations present at the inlet and outlet of a filmcooling hole. The two channels are connected by a single scaled-up film cooling hole with adiameter of 10 mm, an inclination angle of 30°, and a length-to-diameter ratio of 6. Measurements have been performed at various internal crossflow Mach numbers and rib geometries for both parallel and perpendicular orientations of internal and external crossflows. Parallel and v-shaped ribs with quadratic cross-section and four different angles with respect to the internal crossflow direction (45°, 60°, 75°, and 90°) have been placed upstream and downstream of the entrance of the hole at one wall of the cooling passage. The rib height equals the hole diameter, the rib pitch to height ratio is 10. The internal crossflow Mach number has been varied between 0 and 0.37. The data show that placing ribs onto the wall of the coolant passage may result in reduced, unchanged, or even increased discharge coefficients. Internal crossflow Mach number and orientation of the coolant passage in respect to the hole axis have been identified as major influencing parameters.

scholarly journals Measurements of Heat Transfer in Circular, Rectangular and Triangular Ducts, Representing Typical Turbine Blade Internal Cooling Passages Using Transient Techniques

1979 ◽  
Author(s):  
R. W. Ainsworth ◽  
T. V. Jones
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Turbine Blades ◽  
Internal Flow ◽  
Flow Property ◽  
Integral Approach ◽  
Internal Cooling ◽  
Property Variation ◽  
Circular Duct ◽  
Transient Techniques

Internal convection cooling of turbine blades and nozzle guide vanes in jet engines is a method used to prolong the life of those components, which are subjected to very high temperature flows from the engine’s combustion chambers. The cooling is effected by passing cold gas through the internal coolant passages situated in the core of the components, the shape of these passages in many cases being simple duct geometries. Experiments are described in which transient techniques were used in an Internal Flow Facility to measure the flow property variation and heat transfer in various geometries simulating typical internal coolant passages, at conditions representative of those found in engines. Results obtained from the three geometries studied (circular, rectangular, and triangular ducts) are compared with existing experimental data and an integral-approach theoretical prediction. In addition, flow in the circular duct with mass removal representing film cooling mass flow was also studied experimentally, and these results are compared with theoretical predictions.

Sign in / Sign up

Export Citation Format

Share Document