Experimental Study of Thermosolutal convection in Rectangular Enclosures with Vertical Tmperature and Horizontal Concentration Gradients

• Main Authors: Lu, Ming Chu, 盧明初
• Other Authors: Lin Wein Wang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/47810680196568757386

碩士 === 元智工學院 === 機械工程學系 === 84 === The purpose of this study is to investigate the transportphenomena of thermosolutal convection in rectangularenclosures with vertical temperature and horizontalconcentration gradients. The current study isprimarily motivated to gain a better understandingof the multi-layer flow structure caused bythermosolutal convection. The test cell is arectangular enclosure formed with acrylic andcopper plate, which is wrapped with foam insulatorto ensure an adiabatic boundary condition. Thetemperature gradient is maintained uniform andcontrolled by two separate constant-temperature baths,which circulate heated or cooled water through theheat exchanger. The working solution used is aqueouscopper sulphate. An electrochemical method based ona diffusion-controlled electrode reaction will beemployed in this work for creating the concentrationgradient. Flow visualization has been accomplishedusing the particle tracer and shadowgraph technique. Both the temperature and concentration distributionat different time are quantitatively measured. Theconcentration distribution of cupric ions in thesolution is determined by measuring the attenuationof light through the test cell with a 35mW He-Ne laseras the light source. According to Beer's law theconcentration of a solution is proportional to anabsorbency, which is defined as the logarithm of theratio of input and output light intensities. Finally,the relations between the dimensionless mass transferrate Sh and Gr,t as well as Sh and Gr,m are discussed.