Jin Z.,Beihang University |
Wang T.,Beihang University |
Yang M.,Shenyang Aerospace Engine Research Institute
Advanced Materials Research | Year: 2013
The validated finite element method (FEM) was applied to the calculation of local impedance of viscoelastic sample in the acoustic tube. The acoustic impedance of viscoelastic material was calculated by three methods on the basis of numerical acoustic field computed by fluid-structure coupling method and the structure itself. The comparisons of calculation results illustrate that acoustic impedance is the inherent attribute of material. © (2013) Trans Tech Publications, Switzerland.
Liu D.,Beihang University |
Tao Z.,Beihang University |
Luo X.,Beihang University |
Kang W.,Beihang University |
Yu X.,Shenyang Aerospace Engine Research Institute
Applied Thermal Engineering | Year: 2016
This paper presents a theoretical and experimental investigation on developing the relation of concentration-based sealing efficiency and temperature-based sealing efficiency on ingress of transfer by applying the mass and heat transfer analogy. A formula connected these two sealing efficiencies is derived from the Chilton-Colburn analogy. Experiments of heat and mass transfer in ingress are conducted separately to obtain the concentration-based sealing efficiency and temperature-based sealing efficiency respectively, and get a suitable value for the variable "n" originated from the formula derivation. In experiment, annulus Reynolds number is set at 3.25 × 105, rotating Reynolds number is changed from 6.26 × 105 to 8.34 × 105 while the dimensionless sealing air flow rate ranges from 1252 to 5512. The experiment result shows temperature-based sealing efficiency has similar but different distribution inside cavity compared with concentration-based sealing efficiency as Lewis Number is greater than 1 in the experiment. By setting n = 0.105, the experiment data and predicted data from derived formula matches well. In the further discussion of the derived formula, it shows that the difference of concentration-based sealing efficiency and temperature-based sealing efficiency enlarges with the increase of air temperature. © 2016 Elsevier Ltd. All rights reserved.
Li Z.-Y.,Beihang University |
Wang J.-J.,Beihang University |
Qiu M.-X.,Shenyang Aerospace Engine Research Institute
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016
For analysis of dynamic characteristics of aero-engine pipe system, a fluid-structure coupling dynamic model using the user-defined three-dimensional (3D) pipe element was proposed based on the finite element method. The flexural fluid-structure coupling, axial and torsional dynamic behavior of the pipe was considered in the user-defined pipe element. The support was modeled using the nonlinear spring element. The user-defined pipe element was verified through comparisons with the measured data and analytical results. The natural frequencies and responses of a pipe system were calculated. The results show that the natural frequencies and the critical velocity decrease as the fluid pressure increases. And the effects of the nonlinear stiffness coefficient and the excitation amplitude on the pipe system under harmonic base excitation can be obtained. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved.
Zhou K.,Beihang University |
Bian L.,Beihang University |
Zou Z.-P.,Beihang University |
Wang L.,Shenyang Aerospace Engine Research Institute
Tuijin Jishu/Journal of Propulsion Technology | Year: 2013
In order to investigate the effects of heat transfer on performance and flow characteristics of micro radial inflow turbine, one dimensional model for turbine performance has been established with only hub heat transfer due to the structure feature of the micro gas turbine. Then a numeral simulation has been carried out to verify the model as well as to analyze the flow feature of the turbine. Results show that the model is accurate enough to be used to evaluate the effects of heat transfer on the turbine performance. Due to heat transfer, the relative flow angle at the rotor inlet is increased and the flow state in the whole rotor passage is changed. Meanwhile, the output power and efficiency of the micro turbine decrease obviously.
Liu S.,Beihang University |
Wang J.,Beihang University |
Wang J.,Shenyang Aerospace Engine Research Institute |
Hong J.,Beihang University |
Zhang D.,Beihang University
Proceedings of the ASME Turbo Expo | Year: 2010
This study investigated the rigidity and contact state of joint structures that influenced the rotor dynamic characteristics and imbalance response, and the curve for variable structure parameters and the external load. The consideration of rotor joint structures dynamics design was also discussed. The finite-element models were established by using 3D solid elements and surface-to-surface nonlinear contact elements between the interfaces for numerical analysis. The rotor dynamic characteristics were affected by the rigidity of joint structures, and the rotor imbalance response was affected by the contact state of the interfaces. The experimentation for measuring the static rigidity and dynamic contact state of bolted joints with different experimental cycles were performed. Both numerical simulation and experimental results showed that: Firstly, the stiffness of joint structures was not constant. There was a critical load Fcr, when the external load was less than Fcr, the stiffness of joint structures was K1; when the external load was more than Fcr, the bend stiffness of joint structures would drop to K2. The critical load Fcr was influenced by the length of interfaces and preload. Secondly, the contact state of joint structure interfaces varied after a long time of operating with alternating loads. The rotor imbalance was increased by fatigue damage accumulation and irreversible deformation. The study results show that the rigidity and contact state of joint structures vary with external loads and geometry structures, and would affect the rotor system operating. It is advisable to consider the influence of the position, structural parameter and external load of the rotor joint structures on aero-engine structure dynamics design. Copyright © 2010 by ASME.
Cui J.G.,Shenyang Aerospace University |
Zhang L.,Shenyang Aerospace University |
Wang G.H.,Shenyang Aerospace Engine Research Institute |
Cui B.,Shenyang Aerospace Engine Research Institute |
Jiang L.Y.,Shenyang Aerospace University
Applied Mechanics and Materials | Year: 2014
Since the fault of marine gas turbine is difficult to predict accurately, making the rolling bearing as the specific object, a fault prediction model of the marine gas turbine based on Neural Network and Markov method is built through the data analysis, preprocessing and feature extraction for the rolling bearing history test data. First, it uses the neural network method to realize the health state recognition of the marine gas turbine. Then, the fault of the marine gas turbine is predicted by taking advantage of the fault prediction which is based on the Markov model. The results show that the efficiency of fault prediction for the marine gas turbine can be realized better through the fault prediction model constructed in view of the Neural Network and Markov. And it also has a significant practical value in project item. © (2014) Trans Tech Publications, Switzerland.
Huang X.,Nanjing University of Aeronautics and Astronautics |
Wang Y.,Shenyang Aerospace Engine Research Institute |
Sheng L.,Nanjing University of Aeronautics and Astronautics
Proceedings of the American Control Conference | Year: 2015
Propeller synchrophasing control is an active noise control technology with high feasibility and significant effect among various kinds of passive and active methods. A simple and effective synchrophasing control strategy was proposed based on the relationship analysis of phase and angular displacement. Digital simulations and experiments of synchrophasing platform which adopts two propellers driven by servo motors verified that the control strategy can reduce the phase vibration because of external disturbance on propellers. Two synchrophasing control methods, including speed command correction and integrated speed/power command correction, are introduced to solve the synchrophasing control on the existing integrated speed/command control system. Simulation results based on a turboprop engine component level model show that the latter has the merits of rapid response swiftness, high precision and effective suppression of limit circle caused by actuator deadband. © 2015 American Automatic Control Council.
Huang X.,Nanjing University of Aeronautics and Astronautics |
Sheng L.,Nanjing University of Aeronautics and Astronautics |
Wang Y.,Shenyang Aerospace Engine Research Institute
Journal of Engineering for Gas Turbines and Power | Year: 2014
Propeller synchrophasing is an effective way of reducing interior noise and vibration of turboprop-driven aircraft. However, synchrophasing has achieved limited success in practice for the reason that the predetermined phase angles are not acoustically optimized for maximum noise reduction during all flight conditions. An investigation has been conducted out which includes two folds: first, the noise vector based on laboratory experimental data has been modeled and second, optimal phase to acquire minimum noise is obtained via optimization search. An improved identification method of vector noise model which can be less dependent to noise phase message is presented. Compared with traditional methods, this method can greatly reduce the real-time requirement between phase optimization model and control model or sound acquiring model, so it can eliminate the influence which communication delay brings on identification precision. A synchrophasing experimental platform is established to verify the vector noise modeling. It adopts two propellers-driven servo motors to simulate the interior noise environment of the aircraft. The influence of the date sampling condition on identification is also researched. Ant colony optimization with two improvements is applied to phase optimization of four propellers. Simulation results show that the improved algorithm requires much less calculation. © 2014 by ASME.
Ma C.-W.,Shenyang Aerospace Engine Research Institute
Applied Mechanics and Materials | Year: 2010
Thermal paints, as a kind of temperature sensor, provided a non-intrusive method for surface temperature measurement. Based on chromaticity theory, the system described in this paper realized thermal paints temperature intelligent interpretation with digital image processing and database technology. The system overcome the effects of subjective interpretation, environment light and human color discrimination ability and made the analysis more accurate and consistent than manual interpretation. The digital image acquisition system was described in detail. Cubic spline interpolation algorithm was adopted to process the data in the L*a*b* color space. The system had been applied to measure the surface temperature of aero-engine combustor. The results showed that the system can greatly improve the accuracy of temperature-recognition. © (2010) Trans Tech Publications.
Wang J.,Anhui University of Science and Technology |
Feng Z.,Anhui University of Science and Technology |
Zhang Q.,Anhui University of Science and Technology |
Wu X.,Shenyang Aerospace Engine Research Institute |
Ma S.,Shenyang Aerospace Engine Research Institute
International Journal of Heat and Mass Transfer | Year: 2012
An experimental investigation on overall heat transfer performance of a rectangular channel, in which one wall has periodically placed oblique ribs to enhance heat exchange and cylindrical film holes to bleed cooling air, has been carried out in a hot wind tunnel at different mainstream temperatures, hot mainstream Reynolds numbers, coolant Reynolds numbers and blowing ratios. To describe the cooling effect of combined external coolant film with the internal heat convection enhanced by the ribs, the overall cooling effectiveness at the surface exposed in the mainstream with high temperature was calculated by the surface temperatures measured with an infrared thermal imaging system. The total mass flow rate of cooling air through the coolant channel was regulated by a digital mass flow rate controller, and the blowing ratio passing through the total film holes was calculated based on the measurements of another digital-type mass flow meter. The detailed distributions of overall cooling effectiveness show distinctive peaks in heat transfer levels near the film holes, remarkable inner convective heat transfer effect over entire channel surface, and visible conductive heat transfer effect through the channel wall; but only when the coolant Reynolds number is large enough, the oblique rib effect can be detected from the overall cooling effectiveness; and the oblique bleeding hole effect shows the more obvious trend with increasing blowing ratios. Based on the experimental data, the overall cooling effectiveness is correlated as the functions of Re m (Reynolds number of hot mainstream) and Re c (Reynolds number of internal coolant flow at entrance) for the parametric conditions examined. © 2012 Elsevier Ltd. All rights reserved.