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Kang Y.,China Aviation Powerplant Research Institute | Lin Y.-Z.,Beihang University
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2017

An ultra-low emissions combustor, namely low emission stirred swirl (LESS) combustor was studied, based on a scheme of internally-staged/lean premixed and prevaporized (LPP) combustion. The LESS combustor consists of central pilot stage and outer surrounded coaxially main stage, between which there exists a physical isolation, namely the step height. The existence of step height delayed the pilot and main jets mixing. Experimental and numerical studies were carried out to investigate the influence of the step height on the combustion performance. A single dome rectangular combustor was utilized to conduct the lean lightoff and blowout experiments, and pollutant emission experiments. The experimental results showed that with the increase of step height by 38%, the lean lightoff and blowout fuel air ratio decreased by 57.4% and 37.5%, the NOx emission increased by 35.1%, and the combustion efficiency increased by 1.78%; while the CO, unburned hydrocarbons (UHC) emissions decreased. Furthermore, the total pressure loss was kept nearly constant. Non-reacting and reacting flow fields were numerically investigated to analyze the coupled characteristics of pilot and main jets with different step heights. A comparison of flow characteristics, spray structure, and combustion component as well as temperature field with different step heights was conducted. The numerical results showed that the increase of the step height shifted the peak velocity outwards. The enlargement of the primary recirculation zone (PRZ) resulted in the increase of the combustion efficiency and NOx emission, while the CO, UHC emissions decreeased. © 2017, Editorial Department of Journal of Aerospace Power. All right reserved.

Liu T.,China Aviation Powerplant Research Institute | Li Y.,Beihang University
Tuijin Jishu/Journal of Propulsion Technology | Year: 2017

In order to simulate flow and heat transfer characteristics in turbine blade trailing edge cooling channel, a numerical rotating wedge-shape channel with lateral coolant extraction was modeled. The standard k-ω SST turbulence model was applied for the simulation that focused on the flow and rotation factors on the heat transfer distribution and coolant extraction ratios in wedge-shape channel. At stationary case, the heat transfer level decreases along the channel due to the lateral flow extraction. But rotation compresses the end-wall vortex of the inner corner which causes higher heat transfer of the inner section. The coolant extraction ratio increases from the channel entrance to the end-wall at stationary. And the Reynolds number shows very limited influence. As the rotation number increases, the centrifugal force dominates the coolant extraction ratio. Less coolant are observed for the outlets near the channel entrance and more coolant flow through the down-stream outlets. At 50% radial location, it shows the average extraction ratio. Even more, the coolant mass flow rate ratio gradually decreases to 0 at high rotation number(Ro>0.4). It is also found that the channel orientation shows limited effect on the coolant extraction ratio. © 2017, Editorial Department of Journal of Propulsion Technology. All right reserved.

Li L.,China Aviation Powerplant Research Institute | Wang H.,Xi'an Jiaotong University | Su S.,Xi'an Jiaotong University
Journal of Materials Science and Technology | Year: 2015

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.

Ling C.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials | Year: 2011

In this paper, industry CT scanner, scan principle and industry CT scan technology which apply in the measure and design in some complex box are presented. Industry CT scan technology can effectually measure complex box interior close cavity and some cavity which is too small. It can discover some hidden trouble such as complex box interior bug. It has important instructional significance to reduce measure cost and insure production security. © 2011 Trans Tech Publications.

Liu T.,China Aviation Powerplant Research Institute | Xue L.,China Aviation Powerplant Research Institute | Guo X.,Huazhong University of Science and Technology | Zheng C.-G.,China Aviation Powerplant Research Institute
Fuel | Year: 2014

First-principle calculations based on density functional theory were performed to investigate the micro-mechanism of Hg0 adsorption on α-Fe2O3 (0 0 1) surface in the presence of O 2. Considering O2 is more easily adsorbed on α-Fe2O3 than Hg0, this paper investigated Hg0 adsorption on O2 embedded α-Fe 2O3 (0 0 1) surface to clarify the effect of O2 on the capture of mercury by α-Fe2O3. Theoretical calculations indicate that O2 dissociates in two steps on the surface, leaving one O atom to interact with a surface Fe atom. Hg0 adsorption on O/α-Fe2O3 (0 0 1) surface belongs to weak chemisorption, and the potential energy diagram is provided. Additionally, the study of coverage shows that O atom coverage has a huge impact on Hg 0 adsorption. The adsorption mechanism of Hg0 on the surface changes from weak chemisorption into stronger chemisorption as the O coverage increases from 0.25 to 1 mL, with the largest adsorption energy of -268.1 kJ/mol. © 2013 Elsevier Ltd. All rights reserved.

Lin L.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials | Year: 2011

Tail Rotor Shaft (TRS) is a critical part in Helicopter Transmission System, and its loads are very complicated. This tail rotor shaft is made up of Hub and shaft, which incorporate structure design method used. During the flight, tail rotor shaft should suffer a type of large centrifugal load, due to three high-speed circumrotating. And the life of tail rotor shaft should be affected by the centrifugal load. This article discusses a method that considering the complicated structure of a tail rotor shaft, a set of special centrifugal load applying device and multi-load coordination fatigue test technology are used and carried out the centrifugal load applying triumphantly. © 2011 Trans Tech Publications.

Ning F.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials | Year: 2011

In this paper, the failure of gearbox's input pinion was introduced. According to gearbox structure, the factor of load-excursion was analyzed and a method of correcting gear's helix angle was proposed. Finally, the problem was solved by correcting the gear's helix angle and thinking about the influence of the bushes matting under heat conditions. The calculation method of correcting gear helix angle was proven to be valid by other gearbox tests, and provided a reference for correcting the gear's helix angle of other gearbox's. © 2011 Trans Tech Publications.

Hu B.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials | Year: 2011

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.

Ding W.,China Aviation Powerplant Research Institute
Applied Mechanics and Materials | Year: 2011

This paper performs analyses and studies to a part of the foreign advanced helicopter transmission system technology. It introduces the design train of thought, main component structures and relevant parameters. It will give a reference to engineering technical personnel of the helicopter transmission system. © 2011 Trans Tech Publications.

Pan S.-N.,China Aviation Powerplant Research Institute | Luo J.-Q.,China Aviation Powerplant Research Institute
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2012

Aerodynamic design technology in multidisciplinary optimization was discussed in this paper through the analysis of multidisciplinary design optimization (MDO) for turbine. Complex three-dimensional (3-D) blade profile generation technique was proposed by incorporating the swept stacking axis method and a two-dimensional cascade parametric modelling method based on cascade characteristic parameters and Bezier spline. General restrictions were given through the analysis of the mathematic model used in aerodynamic optimization. And an optimization method was also proposed according to the aerodynamic design and restrictions at different stages. For 3-D aerodynamic simulation, tgrid generation, modelling, solving and post processing can be completed automatically by further programming based on CFX. The optimization results show that an increase of 2.3% in turbine efficiency has been reached, the number of rotating blades reduces by 13.21% and the overall mass of blade decreases by 8.96%.

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