Flow analysis of thermo-bioconvection of gravitaxis microorganisms in Newtonian fluid saturated porous media

• Main Authors: Wang, Chih-Hao, 王志豪
• Other Authors: Sheu, Long-Jye
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/55516289297943704757

碩士 === 中華大學 === 機械工程學系碩士班 === 97 === This thesis investigates the thermo-bioconvection induced by gravitactic microorganisms in Newtonian fluid-saturated porous media. The Darcy model and the Boussinesq approximation are utilized in the momentum equation to simulate flow velocity in the porous media. The local non-equilibrium model is applied by using two equations to separately describe the temperature distributions of solid and liquid phases in the porous media. A constant value of the motile velocity is considered for the gravitactic microorganism. The flow regimes of thermo-bioconvection is discussed in terms of dimensioinless parameters such as thermal Rayleigh number, bioconvection Rayleigh number, Pelect number and the interface heat transfer coefficient. The results show that the temperature gradients decrease with the increase of dimensionless interface heat transfer coefficient (H). As a result, the thermo-bioconvection is repressed. As the thermo-Rayleigh number increases, bifurcations that lead to flow patterns with different cells will occur. When bio-Rayleigh number is small, convection and bifurcation will start until large thermo-Rayleigh number is reached. However, thermo-bioconvection could happen at small thermo-Rayleigh number when bio-Rayleigh number is large.