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Tang H.P.,Northwest Institute for Nonferrous Metal Research | Wang Q.B.,Northwest Institute for Nonferrous Metal Research | Yang G.Y.,Northwest Institute for Nonferrous Metal Research | Gu J.,Shenyang Engine Design & Research Institute | And 3 more authors.

Oil–gas separation is a key process in an aero-engine lubrication system. This study reports an innovative development in oil–gas separation. A honeycomb-structured rotor with hexagonal cone-shaped pore channels has been designed, additively manufactured from Ti-6Al-4V using selective electron beam melting (SEBM) and assessed for oil–gas separation for aero-engine application. The Ti-6Al-4V honeycomb structure showed a high compressive strength of 110 MPa compared to less than 20 MPa for metal foam structures. The oil–gas separation efficiency of the honeycomb-structured separation rotor achieved 99.8% at the rotation speed of 6000 rpm with much lower ventilation resistance (17.3 kPa) than that of the separator rotor constructed using a Ni-Cr alloy foam structure (23.5 kPa). The honeycomb-structured Ti-6Al-4V separator rotor produced by SEBM provides a promising solution to more efficient oil–gas separation in the aero-engine lubrication system. © 2016, The Minerals, Metals & Materials Society. Source

Zhang A.,Aircraft Strength Research Institute of China | Xu H.,Shenyang Engine Design & Research Institute | Chen H.,Aircraft Strength Research Institute of China
Jixie Qiangdu/Journal of Mechanical Strength

Fastened joint repair is a main repair method for composite structure with advantages of easy disassembling, high load transferring capacity. It is important to evaluate the residual strength in repair design process. In this paper, the tensile load bearing capacity of metal riveted repair laminates were evaluated by numerical simulation using progressive failure analysis method. Laminate was modeled using shell element whereas the fasteners were modeled by beam elements. MPC technique was adopt to simulate the constraint between fastener and hole. The USDFLD subroutine was used to degrade material stiffness by multi-lever manner while damage occurred. The failure analysis results including failure mode, failure load are in good agreement with test results. The errors of predicted failure loads are with 6%, which shows the proposed method is helpful to composite fastened joint repair design. © 2016, Journal of Mechanical Strength. All right reserved. Source

Mo S.,State Key Laboratory of Virtual Reality Technology and Systems | Mo S.,Beihang University | Zhang Y.,State Key Laboratory of Virtual Reality Technology and Systems | Zhang Y.,Beihang University | And 3 more authors.
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition)

To reveal the multiple-split load sharing mechanism among star gears of 2-stage star gearing system in aero-engine, based on a meshing error analysis made on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing manufacturing error of gear components of the star gear train respectively, and the floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear considered, a refined mathematical model of 2-stage multiple-split loading sharing coefficient calculation was established with the consideration of displacement compatibility, and the load sharing coefficient of system of 1.049 was obtained. ©, 2015, Editorial Department of Journal of Sichuan University. All right reserved. Source

Zhang W.,Shenyang University | Deng M.-C.,Shenyang Engine Design & Research Institute | Li G.-C.,Shenyang University | Wu C.-L.,Shenyang University
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power

Numerically simulated and studied were the air film cooling efficiency of the jet flow from fan-shaped holes with various widths at the outlet at different air blowing ratios. The emphasis was placed on an analysis of the influence of the vortex configuration and vorticity on the cooling efficiency. It has been found that to increase the outlet width will not only decrease the vorticity but also change the direction of the vortex. When the outlet width increases to 2.5 times bigger than that of the inlet diameter, the streamlines of the cooling air at the downstream of the hole center will point to the wall surface from the fuel gas, effectively improving the attachment property of the cooling air. The bigger the outlet width of the air film hole, the higher the cooling efficiency. With an increase of the air blowing ratio, the influence of the outlet width of the air film hole on the cooling efficiency will become more conspicuous. Source

Xu L.-L.,Xiamen University | Ruan C.,Xiamen University | Fang X.-Y.,Xiamen University | Xing F.,Xiamen University | Zhao C.-L.,Shenyang Engine Design & Research Institute
Tuijin Jishu/Journal of Propulsion Technology

Diffuser is one key component of the gas turbine combustor following the compressor. Its primary function is to slow down the air flow delivered by the compressor in order to promote efficient combustion and avoid large total pressure losses. An experimental and computational study of cold flow in the dump diffusers was presented. The main aims were to evaluate the influence of pre-diffuser wall angle and pre-diffuser length on the performance of dump diffusers, and to identify the pressure loss mechanisms. PIV experiments were conducted in a simplified test model to help choose of congruent turbulence model. It was observed that apparent flow separation occurred on pre-diffuser wall when pre-diffuser wall angle amplified to certain degree. The pre-diffuser exit flow was distorted, indicating that the uniform exit conditions typically assumed in the diffuser design were violated. Skew distribution of the pre-diffuser outlet flow can result in strong transverse mixing for liquid, the total pressure loss of pre-diffuser increases significantly. The formula of the total pressure loss coefficient and the pressure recovery coefficient was developed. The optimal pre-diffuser length and pre-diffuser wall angle can be conveniently obtained by this equation, the calculation error was less than 5%. ©, 2015, Editorial Office of Journal of Propulsion Technology. All right reserved. Source

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