Modeling and experimental analysis of AlGaN MOVPE in commercial vertical high-speed rotating-disk reactors

2004 ◽  
Vol 261 (2-3) ◽  
pp. 190-196 ◽  
Author(s):  
K.M. Mazaev ◽  
A.V. Lobanova ◽  
E.V. Yakovlev ◽  
R.A. Talalaev ◽  
A.O. Galyukov ◽  
...  
1994 ◽  
Author(s):  
Robert C. Walker ◽  
Alan G. Thompson ◽  
Gary S. Tompa ◽  
Peter A. Zawadzki ◽  
Alexander Gurary

2004 ◽  
Vol 266 (1-3) ◽  
pp. 354-362 ◽  
Author(s):  
A. Lobanova ◽  
K. Mazaev ◽  
E. Yakovlev ◽  
R. Talalaev ◽  
A. Galyukov ◽  
...  

1994 ◽  
Vol 61 (1) ◽  
pp. 186-191 ◽  
Author(s):  
Kai-Yuan Yeh ◽  
R. P. S. Han

A rotating disk with varying thickness and inhomogeneity, and subjected to a steady, inhomogeneous temperature field is analyzed. To handle the arbitrary profile, the disk is discretized into a series of uniform annular disks possessing constant material properties and then solved by the step-reduction method. Analytic expressions for thermoelastic stresses are given, and based on these results, the formulation is extended to include the calculation of shrink fit, the solving of the inverse problem for equistrength rotating disks, and the computations of plastic stresses and creep at elevated temperatures.


2011 ◽  
Vol 40 (10) ◽  
pp. 1484-1489
Author(s):  
余春晖 YU Chun-hui ◽  
李春波 LI Chun-bo ◽  
柴金龙 CHAI Jin-long ◽  
江展洪 JIANG Zhan-hong ◽  
李景镇 LI Jing-zhen ◽  
...  

Author(s):  
Qingfeng Xia ◽  
David R. H. Gillespie ◽  
Andrew K. Owen ◽  
Gervas Franceschini

Prediction of contact temperature between two materials in high-speed rubbing contact is essential to model wear during unlubricated contact. Conventionally, assumptions of either a steady or an annular heat source are used for slow and high speed rotation, respectively. In this paper, a rotating heating source is solved using an in-house finite element method code. This captures the full geometry and rotating speed of the rubbing bodies. Transient heat transfer is modeled quasi-statically, eliminating the need for a transient 3D simulation. This model is shown to be suitable for contact temperature prediction over a wide range of rotating speeds, anisotropic thermal conductivity, and nonuniform thermal boundary conditions. The model calculates heat partition accurately for a thin rotating disk and short pin combination, which cannot be predicted using the existing analytical solutions. The method is validated against ansys mechanical and experimental infrared thermography. Results demonstrate that the annular source assumption significantly underpredicts contact temperature, especially at the rubbing interface. Explicit modeling of a thin disk results in higher heat partition coefficients compared with the commonplace semi-infinite length assumption on both static and rotating components. The thermal anisotropy of tuft-on-disk configurations is evaluated and compared to a uniform pin-on-disk configuration. Despite the effective thermal conductivity (ETC) in the bristle tuft being approximately 1 order of magnitude lower than along the bristle length (treating the bristle pack as a porous medium), its impact on heat partition and contact temperature is shown to be limited.


2005 ◽  
Vol 51 (6-7) ◽  
pp. 241-248 ◽  
Author(s):  
T. Leiknes ◽  
M. Lazarova ◽  
H. Ødegaard

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.


2019 ◽  
Author(s):  
Rinaldi Sergio ◽  
Domenico Umbrello ◽  
Stefania Rizzuti ◽  
Barbara Mocchi

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