A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor.Four typica...A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor.Four typical hole shapes are considered for the GE-E3 blade.The impact of the additional flow angle(E)within each hole shape on the temperature field is investigated.The results indicate that for the leading edge area and suction surface,the fan-shaped hole case performs best in decreasing temperatures,with a decrease of about 43 K.This is mainly due to the fact that the fan-shaped hole has the maximum expansion in hole spanwise direction.For the pressure surface,the console hole case performs best in decreasing temperatures,with a maximum reduction of about 47.2 K.The influence of E on the surface temperature at leading edge area varied between the different hole shapes.For the cylinder hole and console hole,the E=-20°case has the lowest area-averaged temperature.Because both the fan-shaped hole and the 7-7-7 shaped hole are expansion holes,the pattern of variation of the leading edge area temperature with increasing E is similar for the fan-shaped hole case and 7-7-7 shaped hole case.The E=20°case shows the lowest spanwise-averaged temperature near the hole outlet,and the E=-20°case shows the lowest spanwise-averaged temperature further downstream.展开更多
Wind turbines(WTs)face a high risk of failure due to environmental factors like erosion,particularly in high-precipitation areas and offshore scenarios.In this paper we introduce a novel computational tool for the fas...Wind turbines(WTs)face a high risk of failure due to environmental factors like erosion,particularly in high-precipitation areas and offshore scenarios.In this paper we introduce a novel computational tool for the fast prediction of rain erosion damage on WT blades that is useful in operation and maintenance decision making tasks.The approach is as follows:Pseudo-Direct Numerical Simulation(P-DNS)simulations of the droplet-laden flow around the blade section profile are employed to build a high-fidelity data set of impact statistics for potential operating conditions.Using this database as training data,a machine learning-based surrogate model provides the feature of the impact pattern over the 2-D section for given wind and rain conditions.With this information,a fatigue-based model estimates the remaining lifetime and erosion damage for both homogeneous and coating-substrate blade materials.This prediction is done by quantifying the accumulated droplet impact energy and evaluating operative conditions over time periods for which the weather at the installation site is known.In this work,we describe the modules that compose the prediction method,namely the database creation,the training of the surrogate model and their coupling to build the prediction tool.Then,the method is applied to predict the remaining lifetime and erosion damage to the blade sections of a reference WT.To evaluate the reliability of the tool,several site locations(offshore,coastal,and inland),the coating material and the coating thickness of the blade are investigated.In few minutes we are able to estimate erosion after many years of operation.The results are in good agreement with field observations,showing the promise of the new rain erosion prediction approach.展开更多
An experimental study was conducted to quantify the flow characteristics of the wall jets pertinent to trailing edge cooling of turbine blades.A high-resolution stereoscopic particle image velocimetry(PIV)system was u...An experimental study was conducted to quantify the flow characteristics of the wall jets pertinent to trailing edge cooling of turbine blades.A high-resolution stereoscopic particle image velocimetry(PIV)system was used to conduct detailed flow field measurements to quantitatively visualize the evolution of the unsteady vortices and turbulent flow structures in the cooling wall jet streams and to quantify the dynamic mixing process between the cooling jet stream and the mainstream flows.The detailed flow field measurements were correlated with the adiabatic cooling effectiveness maps measured by using pressure sensitive paint(PSP)technique to elucidate underlying physics in order to explore/optimize design paradigms for improved cooling effectiveness to protect the critical portions of turbine blades from harsh environments.展开更多
Noise prediction from streamlined bodies such as wind turbine blades can be predicted accurately using CFD computations that use spatio-temporal turbulence models at the expense of high computational power.In this wor...Noise prediction from streamlined bodies such as wind turbine blades can be predicted accurately using CFD computations that use spatio-temporal turbulence models at the expense of high computational power.In this work,empirical methods proposed from BPM,Grosveld and Lowson are used to compute numerically to analyse the influence of rotor solidity factor on broadband trailing edge noise from a 2 MW horizontal axis wind turbine with a blade length of 37 m.Inputs to acoustic solver are the velocity vector field and boundary layer data which are obtained using blade element momentum and X-Foil.The outputs from acoustic solver are directivity and far field sound pressure on a receiver located at distance of 120m from tower base.The results have shown that for a wind speed of 10 m/s measured at 10m above ground,sound power level was found to increase between mid-bands to high frequencies for all three methods.Rotor solidity effect was illustrated at constant rotational speed of 17 RPM and receiver height of 0.5m located in downwind position.A minimum difference of 1.5dBA was found at f~100 Hz for Lowson method and maximum of~2.8dBA at 1 kHz between two and three blade rotor.For BPM and Grosveld methods however,the sound levels were~5dBA lower for two blade rotor than three blade rotor between f~100 Hz and f~1 kHz.The study also demonstrated that as number of blades increase by integral multiples,the effect on noise radiation from trailing edge of blades increase by 2-5dBA due to amplitude modulation.展开更多
The adiabatic film effectivenessηof the counter-inclined film-holes fed by varying internal coolant intake on the turbine vane leading edge model was experimentally investigated.A semi-cylinder model was adopted to m...The adiabatic film effectivenessηof the counter-inclined film-holes fed by varying internal coolant intake on the turbine vane leading edge model was experimentally investigated.A semi-cylinder model was adopted to model the vane leading edge which was arranged with two-row holes,which located at±15°on both sides.The four Leading edge model with the combinations of hole-shape(simple holes and laid-back holes)and intake structure(plenum and impingement)were tested under four blowing ratios M of 0.5,1.0,1.5,and 2.0.Theηcontours were obtained by the transient measurement technique based on double thermochromic liquid-crystals.The results present that theηis sensitive to the M for the four studied leading edge cases.The addition of impingement enhances theηfor the two studied holes.The film jets make the coolant-flow closed to the target surface,resulting in higherηunder lower M.The core with higherηappears in the downstream area of hole-exit.Theηenhancement can be provided to almost the identical level by adding the impingement-holes and improving the hole-exit shaping in most areas.With increasing M,the jets with stronger exit normal momentum penetrate into the main-flow.The impingement addition may be a more effective program to upgrade theηrelatively to the exit shaping under larger M.Besides,the laid-back holes with impingement case produce the highest film cooling performance among the four cases,providing great potential in the leading edge especially under larger M.展开更多
This paper presented an experimental investigation the effects of the trailing edge cooling on the aerodynamic performance. The experiments were conducted on the low-speed linear cascade tunnel at Northwestern Polytec...This paper presented an experimental investigation the effects of the trailing edge cooling on the aerodynamic performance. The experiments were conducted on the low-speed linear cascade tunnel at Northwestern Polytechnical University. The external aerodynamic characteristics in the 40 percent chord downstream of exit plane were measured using five-hole probe with the different ejection rates. The results showed that the total pressure loss coefficient at the middle spanwise plane increased at first and then it has a decreasing tendency with the increase of ejection ratio. The trailing edge cooling would influence the structure of the turbine cascade outlet flow field. When the ejection rate was 3%,the loss area near the blade endwall would become stronger,but it would become weaker with the 6% ejection ratio. On the whole,the trailing edge cooling had more influence on the profile loss than on the secondary loss.展开更多
基金supported by the National Science and Technology Major Project of China(2017-Ⅲ-0009-0035)。
文摘A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor.Four typical hole shapes are considered for the GE-E3 blade.The impact of the additional flow angle(E)within each hole shape on the temperature field is investigated.The results indicate that for the leading edge area and suction surface,the fan-shaped hole case performs best in decreasing temperatures,with a decrease of about 43 K.This is mainly due to the fact that the fan-shaped hole has the maximum expansion in hole spanwise direction.For the pressure surface,the console hole case performs best in decreasing temperatures,with a maximum reduction of about 47.2 K.The influence of E on the surface temperature at leading edge area varied between the different hole shapes.For the cylinder hole and console hole,the E=-20°case has the lowest area-averaged temperature.Because both the fan-shaped hole and the 7-7-7 shaped hole are expansion holes,the pattern of variation of the leading edge area temperature with increasing E is similar for the fan-shaped hole case and 7-7-7 shaped hole case.The E=20°case shows the lowest spanwise-averaged temperature near the hole outlet,and the E=-20°case shows the lowest spanwise-averaged temperature further downstream.
基金supported by the CERCA programme of the Generalitat de Catalunya,and the Spanish Ministry of Economy and Competitiveness through the“Severo Ochoa Programme for Centres of Excellence in Research and Development”(Grant No.CEX2018-000797-S)Also,the authors acknowledge MCIN/AEI and FEDER Una manera de hacer Europa for funding this work via(Grant No.PID2021-122676NB-I00)。
文摘Wind turbines(WTs)face a high risk of failure due to environmental factors like erosion,particularly in high-precipitation areas and offshore scenarios.In this paper we introduce a novel computational tool for the fast prediction of rain erosion damage on WT blades that is useful in operation and maintenance decision making tasks.The approach is as follows:Pseudo-Direct Numerical Simulation(P-DNS)simulations of the droplet-laden flow around the blade section profile are employed to build a high-fidelity data set of impact statistics for potential operating conditions.Using this database as training data,a machine learning-based surrogate model provides the feature of the impact pattern over the 2-D section for given wind and rain conditions.With this information,a fatigue-based model estimates the remaining lifetime and erosion damage for both homogeneous and coating-substrate blade materials.This prediction is done by quantifying the accumulated droplet impact energy and evaluating operative conditions over time periods for which the weather at the installation site is known.In this work,we describe the modules that compose the prediction method,namely the database creation,the training of the surrogate model and their coupling to build the prediction tool.Then,the method is applied to predict the remaining lifetime and erosion damage to the blade sections of a reference WT.To evaluate the reliability of the tool,several site locations(offshore,coastal,and inland),the coating material and the coating thickness of the blade are investigated.In few minutes we are able to estimate erosion after many years of operation.The results are in good agreement with field observations,showing the promise of the new rain erosion prediction approach.
文摘An experimental study was conducted to quantify the flow characteristics of the wall jets pertinent to trailing edge cooling of turbine blades.A high-resolution stereoscopic particle image velocimetry(PIV)system was used to conduct detailed flow field measurements to quantitatively visualize the evolution of the unsteady vortices and turbulent flow structures in the cooling wall jet streams and to quantify the dynamic mixing process between the cooling jet stream and the mainstream flows.The detailed flow field measurements were correlated with the adiabatic cooling effectiveness maps measured by using pressure sensitive paint(PSP)technique to elucidate underlying physics in order to explore/optimize design paradigms for improved cooling effectiveness to protect the critical portions of turbine blades from harsh environments.
文摘Noise prediction from streamlined bodies such as wind turbine blades can be predicted accurately using CFD computations that use spatio-temporal turbulence models at the expense of high computational power.In this work,empirical methods proposed from BPM,Grosveld and Lowson are used to compute numerically to analyse the influence of rotor solidity factor on broadband trailing edge noise from a 2 MW horizontal axis wind turbine with a blade length of 37 m.Inputs to acoustic solver are the velocity vector field and boundary layer data which are obtained using blade element momentum and X-Foil.The outputs from acoustic solver are directivity and far field sound pressure on a receiver located at distance of 120m from tower base.The results have shown that for a wind speed of 10 m/s measured at 10m above ground,sound power level was found to increase between mid-bands to high frequencies for all three methods.Rotor solidity effect was illustrated at constant rotational speed of 17 RPM and receiver height of 0.5m located in downwind position.A minimum difference of 1.5dBA was found at f~100 Hz for Lowson method and maximum of~2.8dBA at 1 kHz between two and three blade rotor.For BPM and Grosveld methods however,the sound levels were~5dBA lower for two blade rotor than three blade rotor between f~100 Hz and f~1 kHz.The study also demonstrated that as number of blades increase by integral multiples,the effect on noise radiation from trailing edge of blades increase by 2-5dBA due to amplitude modulation.
基金support of the National Natural Science Foundation of China(Grant No.51776173)the Innovation Capacity Support Plan in Shaanxi Province of China(Grant No.2019KJXX-065)+1 种基金the Scientific Research Plan Project of Key Laboratory of Shaanxi Provincial Education Department(Grant No.17JS070)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX201913)。
文摘The adiabatic film effectivenessηof the counter-inclined film-holes fed by varying internal coolant intake on the turbine vane leading edge model was experimentally investigated.A semi-cylinder model was adopted to model the vane leading edge which was arranged with two-row holes,which located at±15°on both sides.The four Leading edge model with the combinations of hole-shape(simple holes and laid-back holes)and intake structure(plenum and impingement)were tested under four blowing ratios M of 0.5,1.0,1.5,and 2.0.Theηcontours were obtained by the transient measurement technique based on double thermochromic liquid-crystals.The results present that theηis sensitive to the M for the four studied leading edge cases.The addition of impingement enhances theηfor the two studied holes.The film jets make the coolant-flow closed to the target surface,resulting in higherηunder lower M.The core with higherηappears in the downstream area of hole-exit.Theηenhancement can be provided to almost the identical level by adding the impingement-holes and improving the hole-exit shaping in most areas.With increasing M,the jets with stronger exit normal momentum penetrate into the main-flow.The impingement addition may be a more effective program to upgrade theηrelatively to the exit shaping under larger M.Besides,the laid-back holes with impingement case produce the highest film cooling performance among the four cases,providing great potential in the leading edge especially under larger M.
文摘This paper presented an experimental investigation the effects of the trailing edge cooling on the aerodynamic performance. The experiments were conducted on the low-speed linear cascade tunnel at Northwestern Polytechnical University. The external aerodynamic characteristics in the 40 percent chord downstream of exit plane were measured using five-hole probe with the different ejection rates. The results showed that the total pressure loss coefficient at the middle spanwise plane increased at first and then it has a decreasing tendency with the increase of ejection ratio. The trailing edge cooling would influence the structure of the turbine cascade outlet flow field. When the ejection rate was 3%,the loss area near the blade endwall would become stronger,but it would become weaker with the 6% ejection ratio. On the whole,the trailing edge cooling had more influence on the profile loss than on the secondary loss.
