Conjugate free convection heat transfer in vertical eccentric annuli.

摘要

Conjugate laminar free convection heat transfer in vertical eccentric annuli is numerically investigated. Heat transfer parameters such as temperature, heat flux and bulk mean temperature have been numerically obtained for a fluid of Prandtl number, Pr = 0.7 in the eccentric annulus at different values of eccentricity, radius ratio, wall thickness and conductivity ratio. In addition to these parameters, the effect of conductivity ratio, eccentricity, wall thickness and radius ratio on channel height, required to induce specific flow rate, has also been investigated. The analysis has been carried out for two different pairs of thermal boundary conditions. One pair of boundary conditions comprises of one wall kept isothermal at inlet fluid temperature while the other wall heated isothermally whereas the other pair of boundary conditions consists of one wall kept adiabatic while the other wall heated isothermally. Furthermore, results of the present study are utilized for the first pair of boundary conditions to establish the limits, namely the critical values, for solid-fluid conductivity ratio, above which, and wall thickness, below which, the conjugate effect can be neglected for various eccentricity and radius ratio values. Also, for the second pair of boundary conditions, the optimum values of solid-fluid conductivity ratio and wall thickness, giving the maximum induced flow rate for a given channel height, have been obtained for various radius ratio and eccentricity, values.