An investigation of transient three-dimensional buoyancy-driven flow and heat transfer in a closed horizontal annulus
Abstract Buoyancy-driven flow and heat transfer in a horizontal annulus bounded by two impermeable boundaries in the axial direction are numerically investigated in this work. A transient three-dimensional analysis of the end effects on heat transfer and the corresponding flow field is presented. The effects of the axial impermeable boundaries are shown to be characterized by retardation of the flow field through the viscous shearing force in regions near the end walls. The results show that the temperature distribution remains unchanged in the core region provided that the annulus length to outer radius ratio is larger than a critical value. Flow and temperature fields are found to be symmetrical with respect to the mid-axial plane of the annulus. A number of interesting features resulting from the sudden heating of the inner cylinder are presented. Finally, a thorough presentation of formation of flow and temperature fields as a result of the sudden heating of the inner cylinder is given.
A finite‐difference method of high‐order accuracy for the solution of three‐dimensional transient heat conduction problems
A finite-difference method is presented for solving three-dimensional transient heat conduction problems. The method is a modification of the method of Douglas and Rachford which achieves the higher-order accuracy of a Crank-Nicholson formulation while preserving the advantages of the Douglas-Rachford method: unconditional stability and simplicity of solving the equations at each time level. Although the method has not yet been applied, the analysis in this paper suggests that it will prove to be the most efficient method yet proposed for the numerical integration of three-dimensional transient heat conduction problems.
Die Wärmeübertragung in zylindrischen Luftschichten bei natürlicher Konvektion
ZusammenfassungDie in dieser Zeitschrift veröffentlichten Untersuchungen vonBeckmann2) sind an der Versuchsanlage nach Abb. 1 nachgeprüft worden. Als Ergebnis der Untersuchung kann gesagt werden, daß für die Wärmeübertragung in ruhenden zylindrischen Luftschichten die Folgerungen der Ähnlichkeitslehre durchaus bestätigt werden und daß die Gültigkeit des vonBeckmann für die Benutzung in der Praxis aufgestellten Nomogramms8) auch für einen wesentlich höheren Temperaturbereich, als den von ihm untersuchten, belegt ist.