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Qiu S.,AVIC Commercial Aircraft Engine Co. | Deng X.,AVIC Commercial Aircraft Engine Co.
30th Congress of the International Council of the Aeronautical Sciences, ICAS 2016 | Year: 2016

The overall aerodynamic performance of the fan blade of a high bypass ratio aero engine is not only determined by its conventional aerodynamic parameters, such as pressure ratio and efficiency, but also the mass flow ratio of ingested water in the bypass duct during rain ingestion airworthiness test. To ensure the engine reliablibity, the larger percentage of ingested water passing through the bypass duct is always desirable. In conventional fan blade airfoil design practice, the pressure ratio and efficiency are first preliminarily determined for the design point, usually the cruise condition, and the mass flow ratio of ingested water in bypass duct is then calulated for the approach condition for the accessment of its rain ingestion performance. With this approach, many iterations are usually needed before the ideal design results can be obtained, and such interations can be a considerable part of the design cost. To accelerate the design procedure, a multi-point optimization method is proposed in this paper to consider the multipal factors, i.e. the pressure ratio, efficiency and the mass flow ratio of ingested water, all together. In this method, the Bezier curve is used to parameterize the fan blade. The geometrical parameters are used as variables while the pressure ratio, efficiency, and the mass flow ratio of ingested water in bypass duct of the fan blade are used as the objective functions. The flow-field of fan rotor under water ingestion conditions is evaluated by ANSYS CFX. An Eulerian-Lagrangian approach is used in formulating the flow and droplet governing equations in the rotating reference frame. In order to resolve the difficulty of this high-dimensional multi-objective optimization problem, the NSGA-II algorithm is used to obtain a more complete picture regarding the trade-off among pressure ratio, efficiency and water mass ratio in bypass duct under three typical conditions. A multi-point design optimization of a typical high bypass ratio fan blade is performed in this paper. The mass flow ratio of ingested water in bypass duct of the optimized fan blade is much larger than that of the baseline, while the pressure ratio and efficiency of the blade remain unchanged. The feasibility and efficiency of this optimization method are shown by this work.


News Article | May 5, 2017
Site: phys.org

The takeoff of the C919 bought cheers and applause from hundreds of invited guests at Shanghai Pudong International Airport and was broadcast live on Chinese state television. The jet soon became invisible on a windy and polluted day in Shanghai, which was also in the path of dense sandstorms from the north. After the 1 ½ hour flight was over, the test pilots came down smiling from the plane, wearing orange overalls with the Chinese flag. With the flight, the official Xinhua News Agency said China had become "one of the world's top makers of jumbo aircraft," becoming the fourth large jet producer after the U.S., Europe and Russia. China is touting the C919 as a rival to single-aisle jets such as the Airbus A320 and Boeing 737. It was originally due to begin flying in 2014 and be delivered to buyers in 2016, but has been beset by delays blamed on manufacturing problems. It's now unlikely to carry commercial passengers until at least 2019. Mohshin Aziz, a Kuala Lumpur-based aviation analyst at Maybank Kim Eng Securities, said it wouldn't be clear for 7-9 years whether the C919 can make a dent in Airbus and Boeing's duopoly. "This is just the test flight," he said. "Eventually it needs to have some cornerstone customers, of which it will have because there are state-owned airlines, some of them are going to be forced to use it." The aircraft's maker, state-owned Commercial Aircraft Corp. of China Ltd., or Comac, will seek certification from China's civil aviation authority and foreign regulators before making any deliveries. Bao Pengli, deputy director of Comac's project management department, said Thursday the manufacturer planned to make two planes a year from now to 2019 to obtain proof of safe flight before any mass production is started. Comac says it has 570 orders from 23 domestic and foreign customers. Most are state-owned Chinese airlines. The handful of foreign customers includes GE Capital Aviation Services and Thailand's City Airways. The plane can be configured with 155-175 seats and has a standard flight length of 4,075 kilometers (2,530 miles). The jet's development is a key step on the path laid out by Chinese leaders to transform the country from the world's low-cost factory into a creator of profitable technology. At the same time, China's aviation market is growing rapidly as a rising middle class travels more for leisure and business. Boeing forecasts that an annual 6 percent growth in China's air passenger traffic over the next two decades will create demand for 6,810 new planes worth a total of $1 trillion—the first trillion-dollar aviation market in its forecast. Of the new planes, 75 percent are expected to be single-aisle. Airbus has five joint ventures in China, including a factory that assembles A320s in Tianjin, a port city near Beijing, that opened in 2008. Mohshin said much of China's aircraft technology started from Russia, and the Tianjin factory has since given China's supply chain vital experience. "I would say that a lot of their technology mirrors Airbus," he said. Comac says more than 200 Chinese companies and 36 universities have been involved in research and development of the C919. But it relies on foreign-made technology for critical systems, including its engines, which are made by CFM International, a joint venture between General Electric's aviation subsidiary and France's Safran Aircraft Engines. The first deliveries of Chinese-developed engines are expected in 2020, according to the company tasked with making them, AVIC Commercial Aircraft Engine Co. Ltd. Airbus delivered 153 aircraft to Chinese operators last year, including 141 from the A320 family, Eric Chen, president of Airbus Commercial Aircraft China, said in an emailed statement. "We believe C919 will bring new competition to the market," he said. "And we welcome competition, which is good for the development of the industry." Boeing says it delivered more than 160 planes to China in 2016, and more than half of China's fleet are Boeing planes. China's first domestically made commercial jet, the twin-engine regional ARJ-21, flew its first passengers in June 2016, eight years after its first test flight. That smaller jet is a rival to aircraft made by Bombardier Inc. of Canada and Brazil's Embraer SA.


News Article | May 5, 2017
Site: hosted2.ap.org

(AP) — The first large Chinese-made passenger jetliner completed its maiden test flight on Friday, a milestone in China's long-term goal to break into the Western-dominated aircraft market. The takeoff of the C919 bought cheers and applause from hundreds of invited guests at Shanghai Pudong International Airport and was broadcast live on Chinese state television. The jet soon became invisible on a windy and polluted day in Shanghai, which was also in the path of dense sandstorms from the north. After the 1 ½ hour flight was over, the test pilots came down smiling from the plane, wearing orange overalls with the Chinese flag. With the flight, the official Xinhua News Agency said China had become "one of the world's top makers of jumbo aircraft," becoming the fourth large jet producer after the U.S., Europe and Russia. China is touting the C919 as a rival to single-aisle jets such as the Airbus A320 and Boeing 737. It was originally due to begin flying in 2014 and be delivered to buyers in 2016, but has been beset by delays blamed on manufacturing problems. It's now unlikely to carry commercial passengers until at least 2019. Mohshin Aziz, a Kuala Lumpur-based aviation analyst at Maybank Kim Eng Securities, said it wouldn't be clear for 7-9 years whether the C919 can make a dent in Airbus and Boeing's duopoly. "This is just the test flight," he said. "Eventually it needs to have some cornerstone customers, of which it will have because there are state-owned airlines, some of them are going to be forced to use it." Mohshin said other potential customers would wait to see what experience the first customers have. "You are not going to spend a lot of money on something you don't know," he said. The aircraft's maker, state-owned Commercial Aircraft Corp. of China Ltd., or Comac, will seek certification from China's civil aviation authority and foreign regulators before making any deliveries. Bao Pengli, deputy director of Comac's project management department, said Thursday the manufacturer planned to make two planes a year from now to 2019 to obtain proof of safe flight before any mass production is started. Comac says it has 570 orders from 23 domestic and foreign customers. Most are state-owned Chinese airlines. The handful of foreign customers includes GE Capital Aviation Services and Thailand's City Airways. The plane can be configured with 155-175 seats and has a standard flight length of 4,075 kilometers (2,530 miles). The jet's development is a key step on the path laid out by Chinese leaders to transform the country from the world's low-cost factory into a creator of profitable technology. At the same time, China's aviation market is growing rapidly as a rising middle class travels more for leisure and business. Boeing forecasts that an annual 6 percent growth in China's air passenger traffic over the next two decades will create demand for 6,810 new planes worth a total of $1 trillion — the first trillion-dollar aviation market in its forecast. Of the new planes, 75 percent are expected to be single-aisle. Airbus has five joint ventures in China, including a factory that assembles A320s in Tianjin, a port city near Beijing, that opened in 2008. Mohshin said much of China's aircraft technology started from Russia, and the Tianjin factory has since given China's supply chain vital experience. "I would say that a lot of their technology mirrors Airbus," he said. Comac says more than 200 Chinese companies and 36 universities have been involved in research and development of the C919. But it relies on foreign-made technology for critical systems, including its engines, which are made by CFM International, a joint venture between General Electric's aviation subsidiary and France's Safran Aircraft Engines. The first deliveries of Chinese-developed engines are expected in 2020, according to the company tasked with making them, AVIC Commercial Aircraft Engine Co. Ltd. Airbus delivered 153 aircraft to Chinese operators last year, including 141 from the A320 family, Eric Chen, president of Airbus Commercial Aircraft China, said in an emailed statement. "We believe C919 will bring new competition to the market," he said. "And we welcome competition, which is good for the development of the industry." Boeing says it delivered more than 160 planes to China in 2016, and more than half of China's fleet are Boeing planes. China's first domestically made commercial jet, the twin-engine regional ARJ-21, flew its first passengers in June 2016, eight years after its first test flight. That smaller jet is a rival to aircraft made by Bombardier Inc. of Canada and Brazil's Embraer SA. AP news assistant Fu Ting in Shanghai contributed to this report. Watt reported from Beijing. Follow her on Twitter at twitter.com/louise_watt


Deng H.,Beihang University | Qiu L.,Beihang University | Tao Z.,Beihang University | Tian S.,AVIC Commercial Aircraft Engine Co.
International Journal of Heat and Mass Transfer | Year: 2013

Rotation effects on heat transfer in a rotating smooth square U-duct at high rotation numbers have been experimentally investigated via classical copper plate technique. In order to obtain convincing correlations, an extensive heat transfer data are measured. The Reynolds number ranges from 10,000 to 70,000, and the highest rotation number reaches to 2.08. Besides, the mean density ratio maintains around 0.14 in all working conditions. Due to these experimental data, two interesting phenomena are observed in current work. Firstly, in consistent with the previous study, the critical rotation number phenomenon on leading wall (heat transfer on a specific location is weakened by rotation at first, then after a critical Ro, the descending trend is reversed) in radial outward channel is observed. Moreover, we found that the critical Ro varies with dimensionless location parameter X/D. Interestingly, the product of critical Ro and X/D is a constant. Secondly, in radial inward passage, the heat transfer enhancement on leading wall is lower than trailing wall at high rotation numbers, which differs from low Ro scenario. Possible explanations for these two phenomena are proposed. It seems that centrifugal buoyancy force plays an important role in influencing the flow and heat transfer in this channel at high rotation numbers. The interactions of buoyancy and Coriolis force act in different ways in radial outward and inward passages, and are responsible to these phenomena mentioned above. Finally, comprehensive correlations on leading and trailing surfaces in both legs are fitted. The effects of Ro and X/D are included in these correlations simultaneously. © 2013 Elsevier Ltd. All rights reserved.


Jun L.J.,AVIC Commercial Aircraft Engine CO.
Proceedings of the ASME Turbo Expo | Year: 2014

An analytical study was undertaken using the performance model of a two spool direct drive high BPR 300kN thrust turbofan engine, to investigate the effects of advanced configurations on overall engine performance. These include variable bypass nozzle, variable cooling air flow and more electric technique. For variable bypass nozzle, analysis on performance of outer fan at different conditions indicates that different operating points cannot meet optimal performance at the same time if the bypass nozzle area kept a constant. By changing bypass nozzle throat area at different states, outer fan operating point moves to the location where airflow and efficiency are more appropriate, and have enough margin away from surge line. As a result, the range of variable area of bypass nozzle throat is determined which ensures engine having a low SFC and adequate stability. For variable cooling airflow, configuration of turbine cooling air flow extraction and methodology for obtaining change of cooling airflow are investigated. Then, base on temperature analysis of turbine vane and blade and resistance of cooling airflow, reduction of cooling airflow is determined. Finally, using performance model which considering effect of cooling air flow on work and efficiency of turbine, variable cooling airflow effect on overall performance is analyzed. For more electric technique, the main characteristic is to use power off-take instead of overboard air extraction. Power off-take and air extraction effect on overall performance of high bypass turbofan engine is compared. Investigation demonstrates that power offtake will have less SFC. Copyright © 2014 by ASME.


Liang A.,AVIC Commercial Aircraft Engine Co.
Procedia Engineering | Year: 2015

A frequency domain Immersed Boundary (IB) method was developed and validated in the present paper using 2-dimenstional acoustical radiation and scattering cases. The IB method was incorporated with Linearized Euler Equations (LEE) in the frequency domain in the present work. The governing equations were spatially discretisized using the DRP scheme. A pseudo time dependant term was added to the frequency domain equations, allowing the use of a conventional time-marching algorithm to converge the solutions in the pseudo-time domain. Perfectly Matched Layers (PML) were placed at boundaries of computational domain where non-reflective conditions were expected. PML technique was also implemented inside the rigid body to stabilize the computation. The impermeable boundary condition on the surface of the geometry is guaranteed by finding the inverse of an influence matrix, which establishes the relationship between boundary forces and induced velocity. Numerical computations were performed for 2-dimensional acoustic radiation and scattering problems. Computational results were compared with exact solution and yielded good agreement, providing a solid validation of the current method. The method is expected to extend to higher dimension and applied to more complex problem like wake/airfoil interaction simulations in turbomachinery. © 2015 The Authors.


Wu B.,Northwestern Polytechnical University | Yan X.,AVIC Commercial Aircraft Engine Co. | Luo M.,Northwestern Polytechnical University | Gao G.,Northwestern Polytechnical University
Chinese Journal of Aeronautics | Year: 2013

A deduced cutting force prediction model for circular end milling process is presented in this paper. Traditional researches on cutting force model usually focus on linear milling process which does not meet other cutting conditions, especially for circular milling process. This paper presents an improved cutting force model for circular end milling process based on the typical linear milling force model. The curvature effects of tool path on chip thickness as well as entry and exit angles are analyzed, and the cutting force model of linear milling process is then corrected to fit circular end milling processes. Instantaneous cutting forces during circular end milling process are predicted according to the proposed model. The deduced cutting force model can be used for both linear and circular end milling processes. Finally, circular end milling experiments with constant and variable radial depth were carried out to verify the availability of the proposed method. Experiment results show that measured results and simulated results corresponds well with each other. © 2013 Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.


Zhang M.,AVIC Commercial Aircraft Engine Co.
Proceedings of the ASME Turbo Expo | Year: 2016

A diffusion swirling flame under external forcing and selfexcitation within a single swirler combustor have been studied in this paper with the large-eddy simulation and linear acoustic method. The combustor features pre-vaporized kerosene as the fuel, a single radial air swirler for flame stabilization and a square cross section chamber with adjustable length. Firstly, self-sustained pressure oscillation has been achieved by using of a chocked nozzle on the chamber outlet with large-eddy simulation. Dynamic pressure oscillations are analyzed in frequency domain through Fast Fourier Transform. The major pressure oscillation is identified as the 1st order longitudinal mode of the chamber. Further, the same frequency in the form of harmonic velocity oscillation is imposed on the inlet of the combustor while the chamber length has been changed. Based on this approach, a comparative study of the flame response with different excitation method but same frequency is carried out. In both self-excited and forced cases, global and local flame responses as well as Rayleigh index have been analyzed and compared. With the flame response function, the excited acoustic modes under the influence of dynamic heat release have been predicted with linear acoustic method and compared with the results obtained from large-eddy simulation. Results show that the flame response presents a great difference in the spacial distribution with different excitation approaches. Thermo-acoustic interaction distributes along the flame front with the expansion of the flame under self-excitation while it damps with the acoustic propagating downstream under forcing condition. As the ratio of flame length to acoustic wave length could not be neglected for the diffusion swirling flame, the global flame response under forcing cannot represent the local response feature of the flame accurately, thus influencing the instability prediction. Copyright © 2016 by ASME.


Li S.,AVIC Commercial Aircraft Engine Co. | Zhong Y.,AVIC Commercial Aircraft Engine Co.
Proceedings of the ASME Turbo Expo | Year: 2016

A correctly profiled engine nacelle can delay the transition in the boundary layer and allow laminar flow to extend back, resulting in a substantial drag reduction. Therefore, the laminar flow nacelle has lower fuel consumption than current turbulent designs. In this paper, aerodynamic shape optimization of natural laminar flow nacelle has been studied by using a novel nacelle shape design method and transition prediction with CFD. First, the 2D longitudinal profile-line of nacelle is optimized, in order to extend its laminar region and achieve minimum drag coefficient within the design space. Second, the optimized longitudinal profile-line is then circumferentially stacked to construct the 3D nacelle aerodynamic shape. At last, the aerodynamic improvement of the new shape is evaluated by 3D CFD simulation. A nacelle geometry generator has been developed where the deflection angle (related to the curvature) along the cord is controlled by using Non-Uniform Rational BSplines. It is then analytically integrated to obtain the longitudinal profile-line. And also a leading edge matching function is involved in the generator. This technique improves the smoothness of nacelle profile-line, which ensures the curvature and slope of curvature to be continuous all over the nacelle surface. The pressure distribution over the nacelle surface has been improved with no spikes in Mach number. A transition model coupling with shear stress transport turbulent model is used in solving Navier-Stokes equations for transition prediction. An optimization system has been established in combination with the geometry generator, the transition prediction model with CFD, a Kriging surrogate model and a Multi-Island Genetic Algorithm. As a result, the aerodynamic improvement, with one profile-line optimized, is obvious against the original nacelle shape by CFD validation in 3D simulation. The optimized nacelle can achieve a laminar flow up to 23% and its drag coefficient has reduced by 6.5%. It is indicated that the optimization system is applicable in nacelle aerodynamic shape design. © Copyright 2016 by ASME.


Kan R.,AVIC Commercial Aircraft Engine Co | Tian S.,AVIC Commercial Aircraft Engine Co
Proceedings of the ASME Turbo Expo | Year: 2016

A combined impingement-pedestal geometry for turbomachinery double wall cooling application is studied numerically with the shear stress transport turbulence model. Conjugated CFD simulation is performed to investigate the cooling effectiveness distribution. The configuration consists of a high aspect ratio cooling duct, with jet array impinging onto the pin fin-roughed wall. The jet Reynolds number varies from 8,000 to 80,000, jet-To-Target wall spacing is kept constant at Z/Dj=0.8. Three main parameters are investigated, including the jet Reynolds number, pin fin shapes (circular and elongated) and the relative location between jets and pin fins (the jet placed uniformly inside the duct or more densely at the front of the duct). For more detailed investigations, the pin fin diameter and impingement hole diameter are varied independently, and a total of 26 configurations are studied. The results show that the double wall configuration with pin fins significantly increases the heat transfer coefficients, compared to that with only impingement. Non-uniform jet arrangement results in a stronger crossflow and enhances heat transfer on the pins, which brings an increase of cooling effectiveness and more uniform temperature distribution. Copyright © 2016 by ASME.

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