Transient Flow and Heat Transfer Leading to Periodic State in a Square Cavity Due to an Eccentric Circular Rotating Object

• Main Authors: HUANG, XUAN-LONG, 黃選瀧
• Other Authors: SHIH, YANG-CHENG
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/fdj6x3

碩士 === 國立臺北科技大學 === 能源與冷凍空調工程系 === 107 === Many industrial applications involve fluid flow and heat transfer problems in cavities, such as lubricated journal bearings, HVAC systems, devices for electronic cooling, heat exchangers, and collectors of solar energy, etc. Recently, the energy-saving issue has become an important research topic on designing those systems. To this end, the analysis of fluid flow and heat transfer in a square cavity due to an inner eccentric rotating cylinder is the main novel aspect of the present study. One of the active approaches for regulating heat transfer in a convection-dominated cavity system is to use a periodic moving object. In this study, the thermo-hydraulic behavior of an eccentric rotating cylinder with different sizes within a square cavity was investigated numerically. Two-dimensional laminar flow was under consideration. Both isothermal and insulated boundary conditions for the rotating cylinder were considered and the cavity was kept as isothermal and differentially heated enclosures, respectively. The working fluid with Prandtl number equal to five was adopted. The CFD software, ANSYS FLUENT, was used to predict the transient thermo-hydraulic behavior of this study. The dynamic mesh method and overset mesh method were employed to simulate the motion of an eccentric rotating cylinder. According to the numerical results, it is found that the heat transfer efficiency increased significantly with the eccentricity growth, revealing that the rotating object with appropriate eccentricity can enhance the heat transfer within an enclosure.