Effect of temperature sampling methods on sphere packed tube heat transfer coefficient determination

Abstract

This paper investigates the heat transfer characteristics and the pressure drop of a sphere packed tube using Computational Fluid Dynamics (CFD) simulation. The turbulent kinetic energy of the fluid exhibits significant variation based on the differing accumulation structures of the particles, which is deemed to greatly influence the heat transfer characteristics. Consequently, the temperature distribution at the outer wall becomes inhomogeneous. Previous studies have overlooked the relative positioning between the thermocouples and the particles, potentially leading to inaccurate estimations of the heat transfer coefficient and discrepancies between CFD simulations and real-world experiments. To address this, two temperature sampling methods are employed in this paper to estimate the heat transfer coefficients: one method involves measuring the temperatures at various sampling positions, while the other uses the surface average temperature of the packed area as the sample temperature. Interestingly, it is found that different temperature sampling methods significantly impact the heat transfer coefficients. This study serves as a reminder for future research on sphere packed tubes to prioritize temperature sampling positions.