Thermal and efficiency characterization of a low-backlash planetary gearbox: An integrated numerical-analytical prediction model and its experimental validation

Author(s):  
Franco Concli
Author(s):  
Antoine Moreau ◽  
Sébastien Guérin

Abstract This paper is focused on the application of an analytical model, which was previously developed and published for the prediction of buzz-saw noise emitted by supersonic fan rotors. The application test cases are six different fan stages equipped with hardwall inlet ducts and clean inflow conditions. The model is validated through a comparison with experimental sound power levels measured along the working line of each fan in high subsonic, transonic and supersonic regimes. In terms of overall evolution and maximum levels, the model provides a reasonable prediction; the sensitivity to parameters such as the intake axial Mach number or the intake duct length is well reproduced. However the significant discrepancies observed locally show that the prediction of buzz-saw noise is still a difficult task. The model is then extended to the case of distorted mean flow impinging on the rotor. Following this extension, the maximum levels of buzz-saw noise are expected to occur over a wider range of Mach number compared to the case with clean inflow.


Langmuir ◽  
2002 ◽  
Vol 18 (2) ◽  
pp. 405-412 ◽  
Author(s):  
Alexander K. Hipp ◽  
Giuseppe Storti ◽  
Massimo Morbidelli

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Pantelis-Daniel M. Arapoglou ◽  
Athanasios D. Panagopoulos ◽  
Panayotis G. Cottis

Time diversity (TD) has recently attracted attention as a promising and cost-efficient solution for high-frequency broadcast satellite applications. The present work proposes a general prediction model for the application of TD by approximating the time dynamics of rain attenuation through the use of the joint lognormal distribution. The proposed method is tested against experimental data and its performance is investigated with respect to the basic parameters of a satellite link.


2016 ◽  
Vol 14 (4) ◽  
pp. 357-369 ◽  
Author(s):  
Sadam Al-Hazaimay ◽  
Johan A. Huisman ◽  
Egon Zimmermann ◽  
Harry Vereecken

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Jian Zhao ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Yukui Cai ◽  
Qinghua Song

Abstract Ultrasonic burnishing is usually applied to make machined surface modification. The acoustic softening effect caused by ultrasonic vibration is beneficial to the machining of difficult-to-cut materials. In the present work, a burnishing force prediction model was proposed for rotary ultrasonic burnishing of titanium alloy Ti–6Al–4V, whose surface had been machined with the face milling process. Firstly, the contact between the burnishing roller and one single milling mark was analyzed with plane strain assumption based on the Boussinesq–Flamant contact problem. Then, the effect of ultrasonic softening on the yield stress of Ti–6Al–4V was investigated. The critical contact width and contact load that the burnishing roller crushed on one single milling mark were examined to confirm the feasibility of the proposed ultrasonic burnishing force prediction model. The experimental verifications were carried out at various ultrasonic powers. The burnishing forces from experiment measurements were consistent with the calculated results from the proposed model. The mean deviations between theoretical and experimental results of the ultrasonic burnishing force were 10.4%, 12.2%, and 15.2%, corresponding to the ultrasonic power at the level of 41 W, 158 W, and 354 W, respectively.


Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4305 ◽  
Author(s):  
Yuan Xu ◽  
Zhonghua Huang ◽  
Shize Yang ◽  
Zhiqi Wang ◽  
Bing Yang ◽  
...  

Intrabody communication (IBC) has drawn extensive attention in the field of ubiquitous healthcare, entertainment, and more. Until now, most studies on the modeling and characterization of capacitive coupling IBC have been conducted in open space, while influences when using metallic-enclosed environments such as a car, airplane, or elevator have not yet been considered. In this paper, we aimed to systematically investigate the grounding effect of an enclosed metal wall of a vehicle on the transmission path loss, utilizing the finite element method (FEM) to model capacitive coupling IBC in an in-vehicle scenario. The results of a simulation and experimental validation indicated that the system gain in an in-vehicle scenario increased up to 7 dB compared to in open space. The modeling and characterization achieved in this paper of capacitive coupling IBC could facilitate an intrabody sensor design and an evaluation with great flexibility to meet the performance needs of an in-vehicle use scenario.


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