Effect of blockage factor on vegetated channel resistance

2010 ◽  
pp. 247-252
Nanoscale ◽  
2019 ◽  
Vol 11 (37) ◽  
pp. 17368-17375 ◽  
Author(s):  
Inyong Moon ◽  
Sungwon Lee ◽  
Myeongjin Lee ◽  
Changsik Kim ◽  
Daehee Seol ◽  
...  

WSe2 FET oxidized by plasma. Channel resistance decreases exponentially with increasing WSe2 work function, approaching thermal limit.


Author(s):  
Yingying Zhang ◽  
Shijie Zhang

This study proposes a 1D meanline program for the modeling of modern transonic axial multistage compressors. In this method, an improved blockage factor model is proposed. Work-done factor that varies with the compressor performance conditions is added in this program, and at the same time a notional blockage factor is kept. The coefficient of deviation angle model is tuned according to experimental data. In addition, two surge methods that originated from different sources are chosen to add in and compare with the new method called mass flow separation method. The salient issues presented here deal first with the construction of the compressor program. Three well-documented National Aerodynamics and Space Administration (NASA) axial transonic compressors are calculated, and the speedlines and aerodynamic parameters are compared with the experimental data to verify the reliability and robustness of the proposed method. Results show that consistent agreement can be obtained with such a performance prediction program. It was also apparent that the two common methods of surge prediction, which rely upon either stage or overall characteristic gradients, gave less agreement than the method called mass flow separation method.


1966 ◽  
Vol 92 (2) ◽  
pp. 387-409
Author(s):  
David I. H. Barr ◽  
Alan A. Smith ◽  
Thaddeus M. Prus-Chacinski ◽  
E. M. O’Loughlin ◽  
César Farell ◽  
...  

Author(s):  
В.М. Капралова ◽  
И.Ю. Сапурина ◽  
Н.Т. Сударь

AbstractIt is shown that the method for the growth of conducting polyaniline nanotubes, based on the direct polymerization of aniline on the surface of channels in track membranes, can be used to produce nanotubes with a given conductivity. An island-type film with a channel resistance of ~10^19 Ω is formed during the initial stage of polymerization (up to 2 min). As the polymerization duration increases to 3 min, the channel resistance falls by more than 10 orders of magnitude. This is attributed to the formation of a continuous film on the channel surface, i.e., a nanotube is formed. With the polymerization duration increasing further, the channel (nanotube) resistance gradually decreases to ~10^19 Ω at 10 min. The conductivity of polyaniline during the formation of a hollow nanotube is estimated to be 0.01–0.04 S/cm. If the nanotube is completely filled with polyaniline, the conductivity increases to ~0.2 S/cm.


1990 ◽  
Vol 112 (3) ◽  
pp. 328-337 ◽  
Author(s):  
R. P. Dring ◽  
G. C. Oates

Throughflow theory has been limited in its applicability and in its accuracy by the fact that it has not historically been cast in a form that can account for the nonaxisymmetries that naturally arise in turbomachinery flow due to the presence of finite numbers of rotor and stator airfoils. The attempt to circumvent this limitation by the introduction of an aerodynamic blockage factor has been demonstrated in earlier work to produce fundamental inconsistencies in the calculation, which lead to significant errors in the regions of the flow where the nonaxisymmetries are severe. The formulation in Part I of the present work is a derivation of a system of throughflow equations for nonaxisymmetric flow. A benchmark database is used in Part II to provide input to the calculation and to help identify the dominant terms. It is demonstrated that the dominant effect of nonaxisymmetry is contained in two terms that relate the total pressure of the averaged flow to the mass-averaged total pressure. It also is demonstrated that the present formulation produces a result that is more accurate than that obtained with the historical blockage-based formulation.


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