Analysis of the film thickness dependence of a single-phase unidirectional transducer using the coupling-of-modes theory and the finite-element method

1992 ◽  
Vol 39 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Z.H. Chen ◽  
M. Takeuchi ◽  
K. Yamanouchi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Film Thickness ◽  
Single Phase ◽  
Thickness Dependence ◽  
The Finite Element Method ◽  
Element Method

Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

2020 ◽  
pp. 135065012097911
Author(s):  
Xinglong Chen ◽  
James K Mills ◽  
Kai Shi ◽  
Gang Bao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Film Thickness ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Eccentricity Ratio ◽  
The Finite Element Method ◽  
Area Formula ◽  
Static Performance ◽  
Element Method

In this work, to improve the static behavior of aerostatic journal bearings, we examine the effect of pockets with different shapes, including the square, rectangular 1, rectangular 2, and circular, manufactured on the surface of the aerostatic journal bearing. The effects of the pocket shapes, pocket area [Formula: see text], eccentricity ratio ɛ, orifice diameter df, average gas film thickness h0, and misalignment angles [Formula: see text] and [Formula: see text] on the static performance are investigated using simulations. The Reynolds equation is solved by the finite-element method in this work. Simulations reveal that the pocket area [Formula: see text], eccentricity ratio ɛ, gas film thickness h0, orifice diameter df, and misalignment angles [Formula: see text] and [Formula: see text] have a significant influence on the load force F and the stiffness K. In general, rectangular 2 pocket bearings are found to perform somewhat better than bearings with other pocket shapes, with the pocket depth set to one-half of h0, when the pocket area [Formula: see text] varies from one-twelfth to one. The pocket area [Formula: see text] should be set according to the average gas film thickness h0 and the orifice diameter df to achieve a better static performance for the bearings. For bearings operated with misalignment angles [Formula: see text] and [Formula: see text], different pocket areas [Formula: see text] should be set according to the pocket shapes for the optimal design.

scholarly journals Optimal Design of a High-Speed Single-Phase Flux Reversal Motor for Vacuum Cleaners

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3334 ◽  
Author(s):  
Vladimir Dmitrievskii ◽  
Vladimir Prakht ◽  
Vadim Kazakbaev ◽  
Sergey Sarapulov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimal Design ◽  
High Speed ◽  
Single Phase ◽  
The Finite Element Method ◽  
Flux Reversal ◽  
Motor Efficiency ◽  
Rotor Structure ◽  
Element Method

This paper describes the design of a single-phase high-speed flux reversal motor (FRM) for use in a domestic application (vacuum cleaner). This machine has a simple and reliable rotor structure, which is a significant advantage for high-speed applications. An FRM design in which the inner stator surface is entirely used allows it to decrease its volume and increase its efficiency. The mathematical modeling, based on the finite element method, and the optimal design of the high-speed single-phase FRM are described. The criterion of optimization and the selection of a proper optimization algorithm are discussed. Since the finite element method introduces a small but quasi-random error due to round-off accumulation and choosing the mesh, etc., the Nelder-Mead method, not requiring the derivatives calculation, was chosen for the optimization. The target parameter of the optimization is built for the motor efficiency when operating at different loads. Calculations show that the presented approach provides increasing motor efficiency during the optimization, particularly at underload.

Stiffness and Damping of Compressible Lubricating Films Between Computer Flying Heads and Textured Media: Perturbation Analysis Using the Finite Element Method

1991 ◽  
Vol 113 (4) ◽  
pp. 819-827 ◽  
Author(s):  
Y. Mitsuya ◽  
H. Ota
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Film Thickness ◽  
Damping Coefficient ◽  
The Finite Element Method ◽  
Damping Force ◽  
Spacing Variation ◽  
Transverse Roughness ◽  
Stiffness And Damping ◽  
Element Method

Averaged static and dynamic lubrication equations are derived in the general form containing anisotropic film thicknesses dependent on roughness orientation. Solving these equations lead to a presentation of the dynamic characteristics of lubricating films existing between computer flying heads and textured media. Squeeze effects owing to moving roughness accompanying high-frequency spacing variation are found to be given as a function of arithmetically averaged film thickness minus harmonically averaged film thickness. The calculation procedure using the finite element method is then presented for the averaged static and dynamic lubrication equations. Stiffness and damping coefficient are demonstrated indicating the effects of roughness orientation and roughness movement. Under the fixed static film conditions, the roughness decreases the stiffness. In contrast to this, the roughness only slightly affects the damping coefficient. Under fixed load and loading point conditions, these relationships are inversed. It is interesting to note that damping coefficients are decreased by longitudinal roughness and are increased by moving transverse roughness. The reason for this tendency is considered to be that the moving transverse roughness serves to generate the squeeze damping force.

The Finite Element Method for Microchannel Flow and Heat Transfer Calculations

2010 ◽  
Author(s):  
Perumal Nithiarasu
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Single Phase ◽  
Unstructured Mesh ◽  
Microchannel Flow ◽  
The Finite Element Method ◽  
Flow And Heat Transfer ◽  
Selection Of ◽  
Element Method

In this paper, the finite element method for modelling of microchannel flow and heat transfer is discussed. The situations that need unstructured mesh technology are highlighted in addition to the flexible nature of the finite element method for problems with the need for adaptive refinement. Many of these aspects are demonstrated by solving flow and heat transfer through microchannels. Both mechanically driven and electrokinetically driven single phase flows in microchannels are considered. A brief discussion is provided on enhancement methods in which the finite element modelling can help. Only a selection of results are presented in this paper. More results will be presented during the conference.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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