Analogy On Convection Heat Transfer Of The Circumference Surface Of The Disk In Translation And Rotation

With the thermal / transfer analogy principle and naphthalene sublimation technology, this thesis conducted a research on the peripheral surface heat transfer law of disk when the wind speed ranges from 2.46m/s to 22.86m/s during disk translation and rotation.After reviewing the researches concerning disk (or rotating disk) and the convection heat transfer, the author of the present thesis analyzes domestic and international progress on the disk surface researches, points out the purpose and significance of this research and presents the main contents and possible results of the thesis.Based on the main content of wind tunnel test design and naphthalene sublimation requirements, the author puts forward the selection and instructions for use of wind tunnel, test components design and measuring instruments and so on. Moreover, the tables of basic parameters, the amount of naphthalene sublimation and air condition parameter are presented in the smooth peripheral surface heat transfer's naphthalene sublimation experiments.Through the dimensionless treatment for the smooth circumference surface's experimental results, the relationship between the local Nusselt number and the local Reynolds number is obtained. By the analysis of smooth peripheral surface heat transfer of disk during the processes of rotating, and the processes of translation and rotational coupling, we can get the relationship between the properties of smooth peripheral surface heat transfer and wind speed. The local Nusselt numbers of thick disk are without exception less than those of smooth peripheral surface of disk with 20mm in thickness. Furthermore, as the speed of disk increases, the thickness of disk tends to exert a smaller influence on the convective heat transfer.The thesis also conducts a naphthalene sublimation analogy on non-smooth surface structures and obtains the relationships between the local Nusselt number and the local Reynolds number in vertical peripheral surface, horizontal peripheral surface and block peripheral surface respectively. The properties of peripheral surface heat transfer are expounded during the processes of rotating and the processes of translation and rotational coupling. Meanwhile the influence of wind speed on the peripheral surface heat transfer of disk is also analyzed.Confined to the Reynolds number, the structural changes of peripheral surface of disk influence less on the convective heat transfer as the disk rotation speed increases. During the translation and rotational coupling process, the heat transfer coefficients of smooth peripheral surface, vertical peripheral surface, horizontal peripheral surface and block peripheral surface become smaller successively; and what is more, the D -value for corresponding convective heat transfer coefficients of each discrete point are consistent. No matter with or without the influence of wind speed, the convective heat transfer coefficient of smooth peripheral surface is the maximum one, while that of block peripheral surface is the minimum one. On the other hand, the heat transfer effects of vertical and horizontal peripheral surfaces are significantly different because of the impact of different wind speeds.