Experimental research on nonlinear characteristics of natural convection in a 3-D shallow cavity

作     者：ZHAN NaiYan GAO Qing BAI Li YANG Mo 

作者机构：College of Automotive Engineering Jilin University Changchun 130022 China Scool of Municipal and Environmental Engineering Jilin Institute of Architectural and Civil Engineering Changchun 130021 China College of Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2011年第54卷第12期

页      面：3304-3310页

核心收录：

学科分类：080701[工学-工程热物理] 08[工学] 0807[工学-动力工程及工程热物理] 0822[工学-轻工技术与工程] 

基　　金：supported by the National Natural Science Foundation of China (Grant No. 50978120) the Shanghai Leading Academic Discipline Project (Grant No. 05EZ18) the Doctoral Fund Project of Jilin Institute of Architectural and Civil Engineering (Grant No. 861055) 

主　　题：interferometric tomography smoke visualization critical Rayleigh number 3-D characteristic oscillation and chaos 

摘      要：Experiments were conducted to study the temperature field,flow field,3-D characteristics and self-sustained oscillation of the natural air convection in a 3-D shallow cavity which was heated from underneath. The experiments were conducted by the methods of laser holographic interferometry photography and smoke visualization. To ensure the temperature of both plates to be constant and the accuracy of laser interferometer,the instrument was calibrated and error has was analyzed. The results showed that the flow field was stable at lower Rayleigh numbers. When the Rayleigh number increased,the flow field became instable and the isotherms distorted. The rolls merged at Ra=12500 and formed along both axes when Ra was over 18500. The air rose from the middle and descended in the circumference while the flow field and heat transfer converted to 3-D characteristic from 2-D characteristic. When the Rayleigh number increased,the flow field became more instable. The rolls became irregular and time dependent when Ra≥Rac(=30500) ,which is nonlinear. When lateral walls were heated or cooled,the rolls merged along the long axis and two rolls formed along the short axis. Three rolls formed occasionally in the process.