Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
DEALING WITH STAIRCASE GEOMETRIES IN THE NUMERICAL ANALYSIS OF HEAT TRANSFER FROM CURVED SURFACES BY THE LATTICE BOLTZMANN METHOD
Submission Author:
Evani Porto , PR
Co-Authors:
Evani Porto, Stephan Hennings Och, Paulo Philippi
Presenter: Paulo Philippi
doi://10.26678/ABCM.ENCIT2022.CIT22-0172
Abstract
In Purpose – The LBM (Lattice Boltzmann Method) is adopted to numerically simulate and calculate the heat exchange coefficients for single cylinders and a bank of aligned and staggered cylinders. The different layouts are evaluated, to verify the gain in the global heat exchange coefficient. Design/methodology/approach – The method is applied for an incompressible flow, with the employment of the Bhatnagar Gross and Krook (BGK) local collision operator, in a D2Q9 scheme. The computational code is applied for intermediate Reynolds (Re) numbers using a passive-scalar approach for the transport of energy. Findings – The thermal analysis is performed around the obstacles with the calculation of the local and average Nusselt numbers. The results are compared with available data from experimental and computational works. Errors were found to have the same order of magnitude as the dispersion errors between available data. Practical implications – Fluid flow and heat transfer across a bank or bundle of cylinders are relevant for several industrial applications, such as steam generation for boilers or coils applied on air conditioner systems. Normally there is an internal flow inside a tube and a second fluid, with a different temperature, flows externally to perform the heat exchange. In these applications with a bundle of cylinders, the overall heat exchange coefficient is desired to be calculated. Originality/value – Due to its intrinsic cartesian geometry, the use of an LB passive scalar approach for finding the isotherms around curved surfaces requires dealing with staircase geometries. Results show that the method that is proposed in this paper is suitable for evaluating the angular distribution of the local heat transfer coefficient in the range of intermediate Reynolds numbers.
Keywords
Heat transfer, lattice-Boltzmann passive-scalar, bank of cylinders
