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Lei Q.,Beihang University | Zhengping Z.,Beihang University | Huoxing L.,Beihang University | Wei L.,China Aviation Powerplant Research Institute
Computers and Fluids

A detailed experimental and numerical investigation of the unsteady interaction of secondary flow vortices in turbine endwall region was performed with the effect of upstream periodic wakes. The flow field was investigated respectively in a linear turbine cascade and a turbine rotor. The study revealed the physical mechanisms of unsteady interaction between upstream wake and secondary vortices. The influence of the upstream wake on the performance of turbine endwall region was also discussed.The flow field at the exit of the turbine blade row showed a decrease in passage vortex strength and loss due to the upstream wake transport. Two interaction mechanisms are proposed whereby passage vortex loss decreases. They are the upstream wake-pressure side leg of the horseshoe vortex interaction and the upstream wake-passage vortex interaction. The transport of upstream wake can suppress the development of pressure side leg of the horseshoe vortex and passage vortex because of the " negative jet" influence of the wake. © 2010 Elsevier Ltd. Source

Dong W.,Shanghai JiaoTong University | Ding J.,Shanghai JiaoTong University | Zhou Z.X.,China Aviation Powerplant Research Institute
Journal of Aircraft

The de-icing/antiicing system in an aircraft is usually designed to prevent severe ice accumulation on the critical surfaces during flight under an icing environment. Characterizing ice adhesion is critical for effective design of such a system. An experimental apparatus for measuring ice adhesion is developed, and the effects of different factors on ice adhesion are studied through experiments. The ice freezing conditions, material properties, and surface roughness are the main factors for icing adhesion strength. Aluminum and copper with different roughness are used in the present study. A nonlinear and nonmonotonic relationship between the surface roughness and freezing adhesion strength is discovered. The effect of ice freezing temperature on the icing adhesion strength is also studied by experiments. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Li Y.-C.,China Aviation Powerplant Research Institute | Zheng G.-H.,Northwestern Polytechnical University
Hangkong Dongli Xuebao/Journal of Aerospace Power

The application of hydrogen is substantial to the development of aero gas turbine technology. According to the hydrogen application studies in aero gas turbine field, the history of the studies was reviewed and low emission combustion technologies were analyzed. The result indicates that the focus of hydrogen application study in aero gas turbine field has been shifted from early military purpose oriented to civil purpose oriented; the lean burning of primary zone is the key of hydrogen low emission combustion technology; the micro-mix non-premixed diffusive combustion has a great potential to be applied in hydrogen low emission combustion. Source

Li L.,China Aviation Powerplant Research Institute | Wang H.,Xian Jiaotong University | Su S.,Xian Jiaotong University
Journal of Materials Science and Technology

In this work, the effects of ratio of monomer to cross-linker (AM/MBAM) and solid loading on the microstructure and mechanical properties of porous Si3N4 ceramics prepared by tert-butyl alcohol (TBA)-based gel-casting process were investigated. It was found that, when the ratio of monomer to cross-linker was 8, and the solid loading was 50wt%, the mechanical properties of sintered samples were the most excellent, which resulted from the uniform pore size distribution and well-grown rod-like β-Si3N4 grains. In that case, the porosity and flexural strength of sintered samples were 50% and 125MPa, respectively. © 2014. Source

Hu B.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials

On the base of reading up the latest overseas certification specifications and integrating the experience of engineering practice, the requirement for structure fatigue substantiation of helicopter transmission system was expounded, and the related key concepts were explained in detail. Furthermore, the general method for structure fatigue substantiation was presented. Thus, the frame of general principle for structure fatigue substantiation of helicopter transmission systems was basically founded. © 2011 Trans Tech Publications. Source

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