International Journal of Engineering Research and Reviews
ISSN 2348-697X (Online) Vol. 8, Issue 1, pp: (45-53), Month: January - March 2020, Available at: www.researchpublish.com
Thermal Dispersion in a 2D rectangular block Chaitanya Sai Kodali M.Sc Department of Mechanical Engineering, Tennessee Technological University, Tennessee, Cookeville 38501
Abstract: The present work involves the numerical research a pore scale analysis is conducted to explore the actions of microscopic inertia and thermal dispersion in a porous medium. Thermal dispersion in porous media is an import phenomenon for Enhanced Oil Recovery methods including several other engineering applications in combustion and in steam injection systems. The results of thermal dispersion inside cross-flow tubular heat exchangers on heat transfer and temperature zone are numerically examined. Owing to the existence of barriers, thermal dispersion induced by fluid mixing plays a significant role in increasing heat transfer. Accurate calculations of the departure temperature and overall heat transfer rate must also be taken into consideration. The computational process analysis and simulation was developed using the ANSYS method. In this paper, a low Reynolds number flow is considered therefore, flow is regulated by Darcy's law. The present study demonstrates the shift in the centerline temperature values in specific flow directions with variations in relative thermal conductivity magnitude for thermal conductivity of the wood. Keywords: Thermal conductivity, Thermal dispersion, Volume averaging, Tortuosity, Porosity, Reynolds number, Specific heat, grid generation, Representative elementary volume, porous media, gradient operation, liquid composite modeling.
1. INTRODUCTION Our goal in this paper is to concentrate on the concept of thermal dispersion which occurs in the governing equation for non-isothermal flow through porous media. The concept of thermal dispersion increases the possibility of both the porous material's micro-structure and the influence of heat convection. The study of thermal dispersion in porous media typically takes advantage of the notion of representative elementary volume (REV), in which the transport equations are integrated [1–5]. The manufacturing processes of polymer composites such as liquid composite molding (LCM) are one of the most important applications of using thermal dispersion effect in the statistical simulation of the heat equation. Phelan et al.[3] demonstrated that, for single-scale porous material, the traditional volume averaging procedure can be used to extract the transport equation for thermochemical phenomena within the tows. Furthermore, Pedras and Lemos [4] were able to examine thermal dispersion in porous media using the conductivity values of both the solid and liquid phases. Yu determined and mapped out the thermal dispersion profiles of periodic porous structures [5]. In certain situations, an even more difficulty exists in the thermal governing equation owing to the existence of thermal dispersion [6] that occurs as a consequence of heat distribution at the pore size. This spreading is primarily attributed to the molecular heat diffusion, as well as the hydrodynamic mixing induced by the spontaneous fluid flow in a porous media. Greenkorn [7] listed nine mechanisms for the majority of pore-scale thermal spread. Yagi et al. [2] were the first to quantify the successful longitudinal thermal conductivity of the packed bed, taking full account of the thermal dispersion influence, and gradually finding that the longitudinal portion of the dispersion coefficient was much greater than its transverse part. This discovery, in spite of its importance, shocked them so much that they refused to report their findings for several years, according to Wakao and Kaguei [3]. Analytical procedure was recorded by Taylor [6] in a tube. Several theoretical and experimental efforts have since been made (e.g., Aris [7], Koch and Brady [8], Han et al. [9], and Vortmeyer [10]) to create useful associations to approximate thermal dispersion in porous media (see Kaviany [11]). In addition, Kuwahara et al. [12] and Nakayama et al. [13] performed a set of computational experiments by proposing a macroscopically uniform flow through a rod structure to expound the impact on thermal dispersion of microscopic velocity and temperature fields. It is also worth noting that Nakayama et al. [14] extracted from the volume-averaged version of Navier–Stokes and energy equations a thermal dispersion heat flux transmission equation and demonstrated
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