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Qi W.,Nanjing University of Aeronautics and Astronautics | Qi W.,Jiangsu Province Key Laboratory of Aerospace Power System | Xu X.,Nanjing University of Aeronautics and Astronautics
Chinese Journal of Aeronautics | Year: 2015

A mathematic model is proposed for predicting the dynamic properties of fiber reinforced plastic composites (FRP) with interphase. Dynamic properties mainly include loss factors and elastic moduli. The results of elastic moduli from the present model are compared with other models. Elastic moduli E11, E22, G12, G23 and loss factors η11, η22, η12 and η23 of FRP are calculated and a study of the effect of elastic modulus EI and loss factor ηI of interphase on dynamic properties in FRP is carried out here. In this paper, E11 linearly increases with EI, but the growth rate is slow. E22, G12, G23 increase rapidly for lower value of EI. The longitudinal loss factor η11 decreases with the increase of EI in the case of ηI < 0.0026. But η11 linearly increases with EI in larger range of ηI, ηI ≥ 0.0026. On the contrary, transverse loss factor η22, transverse shear loss factors η23 and longitudinal shear loss factors η12 increase with increase of EI in the case of lower value of ηI, but decreases at larger value of ηI. And they also show insensitivity to EI at higher value. © 2015 The Authors.

He X.,Nanjing University of Aeronautics and Astronautics | He X.,Jiangsu Province Key Laboratory of Aerospace Power System | Zhao Z.,Nanjing University of Aeronautics and Astronautics
APISAT 2015 - 7th Asia-Pacific International Symposium on Aerospace Technology | Year: 2015

Triple-swirler plays an important role for high temperature rise combustors of aero-engine. In this paper, experimental investigations were carried out to discuss the effect of triple-swirler rotational direction on flow field. 2D-planar particle image velocimetry (PIV) was adopted in the experiment to acquire the flow field after triple-swirler, and results show that the Central Toroidal Recirculation Zone (CTRZ) is significantly affected by the swirler rotational directions. An obvious CTRZ can be formed by the triple-swirler with co-rotating intermediate swirler and outer swirler, while a much smaller CTRZ was observed with a counter-rotating intermediate and outer swirler. In addition, the pressure probe was set in the inlet and outlet to measure the total pressure, the result shows that the rotational direction plays a key role on the pressure loss coefficient. Furthermore, a modified swirl number is calculated and analysed to help evaluating the swirl flow generated by triple-swirlers.

Jin Y.,Nanjing University of Aeronautics and Astronautics | Jin Y.,Jiangsu Province Key Laboratory of Aerospace Power System | Jin Y.,Co Innovation Center for Advanced Aerospace Engine | Li Y.,Nanjing University of Aeronautics and Astronautics | And 9 more authors.
Applied Energy | Year: 2014

Experimental studies are carried out to investigate cold flow field and combustion performance of a workable liquid-fueled trapped vortex combustor (TVC). A remarkable design of the model is that all the air flows through the combustor is supplied from a single source, which makes it distinct from most of the models mentioned in open literatures. Planar particle image velocimetry (PIV) is used to measure the cold flow field, with particular emphasis placed on vortical flow pattern within cavities, turbulence intensity distribution and interaction between cavity stream and mainstream. The aim of the PIV measurement is to better understand the underlying flow physics in a TVC, as well as to provide a benchmark for validation and improvement of computational models. Combustion experiments are carried out with preheated air (473. K) at atmospheric pressure using liquid kerosene. Flame images at different operating conditions are obtained and the effects of fuel to air ratio (FAR) and inlet Mach number on the physical appearance of flames are clearly revealed. The fuel to air ratio at lean blow out (LBO) is in the range from 0.0043 to 0.0056 as the inlet Mach number varies from 0.15 to 0.30, which indicates good flame stability. The combustion efficiency falls reasonably in the range of 92-100%. The improvement of the radial profile of outlet temperatures indicates the effectiveness of dilution holes. © 2014 Elsevier Ltd.

Jingyu Z.,Nanjing University of Aeronautics and Astronautics | Jingyu Z.,Jiangsu Province Key Laboratory of Aerospace Power System | Xiaomin H.,Nanjing University of Aeronautics and Astronautics | Xiaomin H.,Jiangsu Province Key Laboratory of Aerospace Power System | And 2 more authors.
Applied Thermal Engineering | Year: 2015

Experimental and numerical investigations have been carried out to examine the cooling effect of the liner wall of the cavity zone and the dilution zone in a trapped vortex combustor. The flow field and heat transfer characteristics of three cooling schemes are examined by numerical simulations. Experimental efforts focus on two of the three schemes investigated by numerical simulation, the effects of the inlet temperature, the inlet Mach number and the excess air ratio on the dilution wall temperature are obtained. The results show that, the numerical data agree well with the experimental results. The lowest wall temperature, the highest surface heat transfer coefficient, the highest cooling efficiency are achieved with the impingement/effusion cooling scheme. © 2015 Elsevier Ltd. All rights reserved.

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