Experimental and Numerical Study of Volt-Ampere Characteristics of a Packed Tube Heated by Joule Heating

2021 ◽  
pp. 1-29
Author(s):  
Yi Ran Lu ◽  
Deepak Pudasainee ◽  
Md Khan ◽  
Rajender Gupta ◽  
Petr Nikrityuk
Keyword(s):  
Joule Heating ◽  
Numerical Study ◽  
Fixed Bed ◽  
Internal Heat ◽  
Packed Bed ◽  
Internal Diameter ◽  
Transfer Model ◽  
Numerical Studies ◽  
Chemically Reacting ◽  
Good Agreement

Abstract This work is devoted to experimental and numerical studies of volt-ampere characteristics of a fixed bed heated by the Joule heating. The main feature of this type of fixed bed is internal heat generation using the Joule heat. The application is to provide the heat to chemically reacting gases flowing through the bed reactor. To validate our model a cylindrical packed bed is considered with a height of 11 cm and an internal diameter of 4.8 cm. This bed is filled with 86 balls made of carbon steel with a diameter of 1/2 inches (1.27 cm). For numerical simulation, open-source DEM software is used to generate the cylindrical packed bed. Electric field distribution is calculated using a new particle-unresolved DEM-based model coupled with a discrete heat transfer model to account for the temperature dependency of the electrical conductivity of steel particles. The results of the simulation were found to be in good agreement with experimental data.

Numerical Study of Long Channel Carbon Nanotube Based Transistors by Considering Variation in CNT Diameter

2020 ◽  
Vol 61 ◽  
pp. 78-87
Author(s):  
Sajjad Dehghani
Keyword(s):  
Carbon Nanotube ◽  
Chemical Sensors ◽  
Field Effect Transistors ◽  
Numerical Study ◽  
Electrical Current ◽  
Light Emitters ◽  
Short Channel ◽  
Numerical Studies ◽  
Long Channel ◽  
Good Agreement

While much numerical studies have been done on short channel carbon nanotube field effect transistors (CNT-FETs), there are only a few numerical reports on long channel devices. Long channel CNT-FETs have been widely used in chemical sensors and biosensors as well as light emitters. Therefore, numerical study is helpful for a better understanding of the behavior of such devices. In this paper, we numerically analyze long-channel CNT-FETs by solving the continuity and charge equations self-consistently. To increase the accuracy of simulation, filed-dependent mobility is applied to the equations. Furthermore, a method is proposed to obtain the electrical current of transistors as a function of CNT diameter. Obtained results are in good agreement with the previous experimental data. It is found that compared to a CNT-based resistor, the dependence of current on diameter is much higher in a CNT-FET. Finally, reproducibility of transistors based on the arrays of random CNTs of 1-2 nm diameter in terms of the CNTs number is also investigated.

Experimental and Numerical Study for Gap Resonance of Drillship Moonpool in Waves With/Without Forward Speed

2018 ◽  
Author(s):  
Allan R. Magee ◽  
Aichun Feng ◽  
Kandasamy Karthikeyan ◽  
Xiang Liu ◽  
Deguang Yan
Keyword(s):  
Numerical Study ◽  
Resonance Phenomenon ◽  
Forward Speed ◽  
Following Seas ◽  
Wave Flume ◽  
Trapped Mode ◽  
Numerical Studies ◽  
Gap Resonance ◽  
Piston Mode ◽  
Good Agreement

Experimental and numerical studies are carried out to examine the moonpool gap resonance for a drillship at both stationary position and forward speed conditions. The moonpool size and draft are also changed to study their effects for the gap resonance phenomenon. An OpenFOAM based CFD model is developed and the numerical results show good agreement with model tests. Both piston and sloshing modes gap resonances are clearly observed. The study shows that the resonance frequency and RAO of the wave elevation inside the moonpool are subject to the effects of moonpool length, drill ship draft and ship forward speed. The model test shows that moonpool elevation RAO generally significantly increases in head seas and noticeably decreases in following seas condition. It is interesting to notice that the wave flume sidewall significantly depresses the moonpool elevation RAO at a certain frequency regardless of moonpool length and draft. Further study shows that the presence of the flume sidewall results in a trapped mode that coincides with the moonpool piston mode resonance at zero speed. This depresses the peak of the moonpool resonance, which occurs at the same frequency.

scholarly journals Numerical Study of a Journal Bearing with Scratches: Validation with Literature and Comparison with Experimental Data

Lubricants ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 61
Author(s):  
Anh T. Vo ◽  
Michel Fillon ◽  
Jean Bouyer
Keyword(s):  
Scientific Literature ◽  
Journal Bearing ◽  
Numerical Study ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Rig ◽  
Numerical Studies ◽  
Clear Idea ◽  
Volume Method ◽  
Good Agreement

The lifespan of journal bearings is directly related to the operating conditions they have to face and reducing their maintenance intervals allows one to have a clear idea about their performance when issues occur. The presence of scratches on one of its surfaces degrades the performance of a journal bearing. These effects have already been assessed in experiments; however, numerical studies on this subject are still scarce. This work develops a numerical thermohydrodynamic (THD) program using the finite volume method to simulate the effects of scratches on the performance of journal bearings. To test the validity of the program, the numerical results are compared with the scientific literature and with experimental measurements conducted using the Pprime Institute journal bearing test rig. Some minor discrepancies are observed, but the overall results are in good agreement.

scholarly journals Packed bed column studies for the removal of dyes using novel sorbent

2013 ◽  
Vol 19 (4) ◽  
pp. 461-470 ◽  
Author(s):  
R. Rajeshkannan ◽  
M. Rajasimman ◽  
N. Rajamohan
Keyword(s):  
Flow Rate ◽  
Fixed Bed ◽  
Packed Bed ◽  
Breakthrough Curves ◽  
Column Studies ◽  
Packed Bed Column ◽  
Bdst Model ◽  
Tamarind Seed ◽  
Acid Blue ◽  
Good Agreement

A continuous fixed bed study was carried out by using tamarind seed as a sorbent for the removal of malachite green (MG) and acid blue 9(AB9) from aqueous solution. The effect of factors, such as flow rate and bed depth was studied. Data confirmed that the breakthrough curves were dependent on flow rate and bed depth. Thomas, Adams-Bohart, and Yoon-Nelson models were applied to experimental data to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the packed bed column. Bed depth/service time analysis (BDST) model was used to express the effect of bed depth on breakthrough curves. The results showed that Thomas model was found suitable for the normal description of breakthrough curve at the experimental condition, while Adams-Bohart and Yoon-Nelson model were able to explain only the initial part of dynamic behaviour of the tamarind seed column. The data were in good agreement with BDST model. It was concluded that the tamarind seed can be effectively used as a sorbent for the removal of dyes.

A Numerical Study of Squeeze Film Dampers

2013 ◽  
Author(s):  
Praneetha Boppa ◽  
Gerald L. Morrison ◽  
Aarthi Sekaran
Keyword(s):  
Steady State ◽  
High Speed ◽  
Numerical Study ◽  
Squeeze Film ◽  
Numerical Studies ◽  
Whirling Motion ◽  
Squeeze Film Dampers ◽  
Absolute Frame ◽  
Bearing System ◽  
Good Agreement

Squeeze film dampers (SFDs) are used in the high speed turbomachinery industry as a means to reduce vibration amplitude, provide damping, and improve dynamic stability of the rotor bearing system. Past numerical studies analyzing SFDs, have been computationally expensive and time consuming. The present study investigates the feasibility of applying a steady state solver to obtain computational efficiency while ensuring that the parameters of interest are captured. This is done via the application of the Moving Reference Frame (MRF) solver in ANSYS® Fluent. A steady state solver in an absolute frame of reference was used to produce whirling motion of the rotor. The results are validated by comparison to the experimental data of Delgado [1]. The numerical model shows good agreement with these results.

Finite element studies of reinforced concrete slab - edge column connections with openings

2007 ◽  
Vol 34 (8) ◽  
pp. 952-965 ◽  
Author(s):  
Hong Guan ◽  
Maria Anna Polak
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Large Scale ◽  
Numerical Study ◽  
Concrete Slab ◽  
Reinforced Concrete Slab ◽  
Element Analysis ◽  
Numerical Studies ◽  
Experimental Findings ◽  
Good Agreement

An extended nonlinear layered finite element method (LFEM) is used to investigate the influence of openings and shear stud reinforcement (SSR) on the behaviour of reinforced concrete slab – edge column connections. In all, ten large-scale slab – edge column connections tested previously are analyzed. The laboratory test variables were the size and location of the openings in the vicinity of an edge column and the existence of SSR. The numerical results of the load–deflection response, the ultimate strength, and the crack patterns are compared with the experimental findings and good agreement is achieved. A numerical study on two connections is also carried out to determine the influence of the locations of opening in slab – edge column connections with SSR. Discussion on code provisions for slabs with openings is provided. The comparative and numerical studies confirm the accuracy, reliability, and effectiveness of the LFEM in the analysis of slab – edge column connections with both openings and SSR.Key words:slab–column connection, punching shear, opening, shear stud reinforcement, finite element analysis.

Numerical Study of Modular 5.56 mm Standard Assault Rifle Referring to Dynamic Characteristics

2015 ◽  
Vol 65 (6) ◽  
pp. 431 ◽  
Author(s):  
P. Płatek ◽  
K. Damaziak ◽  
J. Małachowski ◽  
P. Kupidura ◽  
R. Woźniak ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Multibody System ◽  
Numerical Study ◽  
Experimental Tests ◽  
Numerical Approach ◽  
Complex Character ◽  
Strength Parameters ◽  
Numerical Studies ◽  
Modelling Methodology ◽  
Good Agreement

<p>The paper describes investigations carried out to verify a loading mechanism of a newly designed modular assault rifle MSBS-5.56. A complex character of interaction between its elements during a reloading process encouraged the authors implement a numerical approach based on the multibody system to specify the essential dynamic characteristics. The achieved results were compared to the data recorded during the experimental tests on the shooting range. Owing to the proposed modelling methodology, a good agreement between experimental and numerical studies has been achieved.<br />A numerical model presented in the paper will be applied in further investigations to analyse strength parameters of the reloading mechanism and to conduct additional optimisation studies.</p>

scholarly journals MHD-Conjugate Free Convection from an Isothermal Horizontal Circular Cylinder with Joule Heating and Heat Generation

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
NHM. A. Azim ◽  
M. K. Chowdhury
Keyword(s):  
Heat Transfer ◽  
Circular Cylinder ◽  
Skin Friction ◽  
Heat Generation ◽  
Joule Heating ◽  
Numerical Study ◽  
Internal Heat ◽  
Governing Equations ◽  
Generation Parameter ◽  
Horizontal Circular Cylinder

The present work is devoted to the numerical study of laminar magnetohydrodynamic (MHD) conjugate natural convection flow from a horizontal circular cylinder taking into account Joule heating and internal heat generation. The governing equations and the associated boundary conditions for this analysis are made nondimensional forms using a set of dimensionless variables. Thus, the nondimensional governing equations are solved numerically using finite difference method with Keller box scheme. Numerical outcomes are found for different values of the magnetic parameter, conjugate conduction parameter, Prandtl number, Joule heating parameter, and heat generation parameter for the velocity and the temperature within the boundary layer as well as the skin friction coefficients and the rate of heat transfer along the surface. It is found that the skin friction increases, and heat transfer rate decreases for escalating value of Joule heating parameter and heat generation parameter. Results are presented graphically with detailed discussion.

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