The dimensionless Nusselt number data pertaining to a catalytic process of steam-methanol reforming for the production of hydrogen
Description
The dimensionless Nusselt number data are obtained for a catalytic process of steam-methanol reforming for the production of hydrogen. In fluid dynamics, the Nusselt number is the ratio of convective to conductive heat transfer at a boundary in a fluid. Convection includes both advection and diffusion. The conductive component is measured under the same conditions as the convective but for a hypothetically motionless fluid. It is a dimensionless number, closely related to the fluid's Rayleigh number. A Nusselt number value of zero represents heat transfer by pure conduction. A Nusselt number value between zero and 10 is characteristic of slug flow or laminar flow. A larger Nusselt number corresponds to more active convection, with turbulent flow typically in the 100-1000 range. A similar non-dimensional property is the Biot number, which concerns thermal conductivity for a solid body rather than a fluid. The mass transfer analogue of the Nusselt number is the Sherwood number. The Nusselt number is the ratio of convective to conductive heat transfer across a boundary. The convection and conduction heat flows are parallel to each other and to the surface normal of the boundary surface, and are all perpendicular to the mean fluid flow in the simple case. Selection of the characteristic length should be in the direction of growth or thickness of the boundary layer; some examples of characteristic length are: the outer diameter of a cylinder in external cross flow perpendicular to the cylinder axis, the length of a vertical plate undergoing natural convection, or the diameter of a sphere. For complex shapes, the length may be defined as the volume of the fluid body divided by the surface area. The thermal conductivity of the fluid is typically evaluated at the film temperature, which for engineering purposes may be calculated as the mean-average of the bulk fluid temperature and wall surface temperature. In contrast to the definition given above, known as the mean Nusselt number, the local Nusselt number is defined by taking the length to be the distance from the surface boundary to the local point of interest. The mean Nusselt number is obtained by integrating the expression over the range of interest. The Nusselt number may be obtained by a non-dimensional analysis of Fourier's law since it is equal to the dimensionless temperature gradient at the surface. Contributor: Junjie Chen, E-mail address: koncjj@gmail.com, ORCID: 0000-0002-5022-6863, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China
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ANSYS FLUENT is applied to define the terms in the equations relating to conservation, thermodynamics, chemical production rates, and equation of state, and then combine the results to define the problem involving surface chemistry. To describe the surface reaction mechanisms in symbolic form, the following information is required, including the thermochemical properties of surface species in the surface phases, names of the surface species, site densities, names of all surface phases, Arrhenius rate coefficients, reaction descriptions, and any optional coverage parameters.