Numerical simulation of incompressible laminar fluid flow in tubes with wire coil inserts

Numerical simulations of steady incompressible laminar 3D fluid flow with heat transfer in smooth round tubes with wire coil inserts have been accomplished. Four wire coils with different geometrical characteristics of dimensionless pitch (p/d) and wire-diameter (e/d) have been studied for Reynolds numbers lower than 500-700 using the commercial package software FLUENT. The numerical results have been compared with experimental data previously obtained by the authors and a good agreement is reached. These results allow one to know the internal flow structure, to identify the critical Reynolds number of oscillating laminar flow and to obtain practical correlations of the Fanning friction factor. So, the internal flow structure under isothermal conditions has been analyzed and a set of practical correlations of Fanning friction factor have been obtained. The heat transfer enhancement produced by the insertion of helical-wire-coils has also been treated. The preliminary results obtained for uniform heat flux are showed. The developed numerical methodology can be used to assess the heat transfer enhancement produced by other kinds of insert devices, to reduce the experimental efforts and to obtain more reliable correlations for heat exchangers design process. .