Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

A NEW APPROACH TO THE FORMULATION AND SOLUTION OF MULTI-TEMPERATURE CONVECTION PROBLEMS

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.021349
pages 2723-2730

Abstrakt

In many instances convective heat transfer occurs between multiple isothermal boundaries. In this case, heat transfer is driven by more than one temperature difference. This paper summarizes our recent theoretical and applied work on this class of heat transfer problems, namely multi-temperature convection. An extension of the Newton law of cooling was proposed to formulate multi-temperature convection in terms of multiple temperature differences, hence eliminating the need for an effective temperature difference. The coefficients of the proposed formulation can be obtained using a new technique, dQdT, which can be implemented in both analytical and numerical solutions. It has been shown that, under certain conditions, a multi-temperature convection problem can be represented by a thermal-resistor network comprised of multiple temperature nodes, each representing an isothermal boundary, connected through paired convective resistances. In earlier publications, briefly summarized here, the advantages of the extended Newton formulation and the resistor-network model, enabled by the dQdT technique, have been established for a wide range of convection problems. In general, the new approach leads to a simpler presentation of the solution which is more consistent with the physics of the problem, while revealing more detail about the thermal phenomenon. Moreover, using the dQdT results, improved correlations have been developed for classical problems such as laminar forced convection in a concentric annulus and laminar free convection in a tall vertical channel.