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Xiaodong Q.,AVIC Commercial Aircraft Engine Co.
Procedia Engineering | Year: 2015

The design of aero engine turbine disks, which are working under high thermal and centrifugal loads, is an interactive and multidisciplinary process that includes several disciplines, such as aerodynamics, structural analysis, mechanical design, and heat transfer etc. Considering the actual aero-thermal-structure coupled environment, the main challengefor the designersis to produce an optimum design that satisfies all the design criteria such as weight, life, efficiency and reliability. Especially, problems of overweight and maximum localized stress have been always encountered for designers in the preliminary design phase. Therefore, there exist contradictions for the design parameters fromdifferent disciplines, and then multidisciplinary design optimization method could be a very valuableand efficient strategy tosolve the problem. In this paper, based on the platforms of ANSYS workbench software, the aero-thermal-structure coupled analysis of a high pressure turbine disk had been conducted. Then, the parameters of width and height of the disk bore were selected as the design variables, and multidisciplinary design optimization of turbine disk had been done. As a result, with the constraints on strength criteria, the objective function of disk weight had been decreased by 6 percents which achieved the expected goal and significantly reduced the design and research time. © 2015 The Authors.

Qiu L.,Beihang University | Deng H.,Beihang University | Sun J.,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, pressure drop, and thermal performance in a smooth square U-duct have been experimentally investigated. The Reynolds number ranges from 10,000 to 70,000, and the highest Rotation number reaches to 2.08. The density ratio maintains around 0.14 in all working conditions. In current study, a new rotating pressure measurements system is designed and validated. And the Nusselt numbers, friction factors and thermal performances in current study agree well with that in open literature. The experimental results show that the rotating-to-stationary ratios of these three parameters correlate with Rotation number in a very good way. In general, Nusselt number ratio increases linearly with Rotation number, but the friction ratio is oscillating when Rotation number increases. More detailed analysis of rotation effects on heat transfer shows that rotation has most dominate effects on averaged Nusselt number at the sharp turn compared with two straight passages by reinforcing the impingements over there. Due to the influence of sharp turn, rotation effects in second passage become dominant at high Rotation numbers. The friction ratio data suggest that the rotation has more apparent effects on friction ratio in heated channel than unheated channel. The Buoyancy force plays a very important role in channel's friction factor. Generally, it reduces the friction resistance in a smooth U-duct especially at high Rotation numbers. © 2013 Elsevier Ltd. All rights reserved.

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.

Zhang Y.F.,French National Center for Scientific Research | Zhang Y.F.,AVIC Commercial Aircraft Engine Co. | Vicquelin R.,French National Center for Scientific Research
Journal of Computational Physics | Year: 2016

Bulk Reynolds number and bulk temperature are key quantities when reporting results in channel flow simulations. There are situations when one wishes to accurately control these parameters while changing some numerical or physical conditions. A method to control the bulk Reynolds number and the bulk temperature in channel flow simulations is detailed. An ordinary differential equation is prescribed for the additional source term in the momentum balance equation so that the transient regime of the simulation is thoroughly tuned in order to efficiently and accurately reach the target Reynolds number value. A similar treatment is applied for the additional volume heat source term in the energy balance equation. The proposed method is specifically interesting when studying complex multi-physics in channel flow configurations when non-dimensionalization of the equations is no longer practical. © 2015 Elsevier Inc.

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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