A mathematical model for pyrolysis of a solid particle: Effects of the lewis number

1977 ◽  
Vol 55 (1) ◽  
pp. 47-53 ◽  
Author(s):  
L. T. Fan ◽  
Liang-Shih Fan ◽  
Kei Miyanami ◽  
T. Y. Chen ◽  
W. P. Walawender
2021 ◽  
Vol 33 (1) ◽  
pp. 1-8
Author(s):  
K. SREERAM REDDY ◽  
◽  
Ch. MAHESH ◽  

Mathematical model has been developed to protect fluid and solid particle homogeneous mixture velocity concentration and temperature for a heated horizontal flat plate. Conversation equation based on Eulerian scale are approximated for small relaxation times through stream function and similarity transformations. Parametric database generated through computer program for arbitrary constants on comparison with clear fluid reveals the particle concentration has pronounced effect on velocity and temperature profiles.


Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 692 ◽  
Author(s):  
Mohammad Ferdows ◽  
Khairy Zaimi ◽  
Ahmed M. Rashad ◽  
Hossam A. Nabwey

Recently, bioconvection phenomenon has gained great importance in research for its use in many engineering and biological applications. Therefore, this work investigates the magnetohydrodynamic flow of a dissipative nanofluid, including gyrotactic microorganisms along an exponentially moving sheet. Since the governing equations that describe the problem are nonlinear and more complicated, similarity transformations are used to get a reduced mathematical model in which all the differential equations are ordinary and asymmetric. The computational analysis for the reduced mathematical model is carried out, employing the spectral relaxation technique (SRM) via software called MATLAB. Comparison results are also validated by using the boundary value problem solver (bvp4c) in MATLAB. The obtained results were compared with previously published researches, and a high degree of compatibility and accuracy were found symmetric. The implications of pertinent parameters on velocity, temperature, nanoparticles volume fraction, and density of the microorganism profiles are graphically presented. A decline was seen in the velocity field with augmentation in the magnetic parameter, but certain enhancement was noticed in the temperature field for augmented values of the magnetic parameter, thermophoresis, and Brownian motion parameters. A significant reduction was also noticed in the behavior of the concentration profile for augmented values of the Brownian motion parameter and Lewis number, while it was enhanced with the boost in the thermophoresis and magnetic parameters. The results also indicated that the density of the motile microorganism decreases with bioconvection Lewis number, Prandtl number, Lewis, and Peclet numbers.


1977 ◽  
Vol 55 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Kei Miyanami ◽  
Liang-Shih Fan ◽  
L. T. Fan ◽  
W. P. Walawender

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Rong Kang ◽  
Haixiao Liu

In the transportation process of oil and gas, solid particle erosion in pipelines is an inevitable problem. The erosion usually occurs in fittings with changing flow directions, such as elbows. A theoretical model based on mechanism analyses is developed for predicting the solid particle erosion on the symmetry plane of elbows for annular flow. This model is a sort of generalized erosion prediction procedure, which resolves the erosion process into the description of the flow field velocity profile, particle motion rules, and penetration calculation. The 1/7th power law is adopted to represent the velocity profile of gas core, and a linear velocity profile is assigned to the liquid film. The trajectories of particles in the gas core and the liquid film are discretized, and a mathematical model is developed by analyzing external forces acting on particles. The impact speeds and angles of particles can be obtained from the mathematical model, and the penetration ratios are then estimated by incorporating the impingement information of particles into the erosion formulas. By contrast with experimental data, the mechanistic model is validated and indicates advantages in both accuracy and efficiency. Furthermore, the effects of different parameters on penetration ratios are discussed in detail, including the superficial gas velocity, superficial liquid velocity, pipe diameter, particle diameter, curvature radius, and liquid viscosity.


2008 ◽  
Author(s):  
Ishii Akira ◽  
Yoshida Narihiko ◽  
Hayashi Takafumi ◽  
Umemura Sanae ◽  
Nakagawa Takeshi
Keyword(s):  

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