Title of article :
Flow pattern assessment in tubes with wire coil inserts in laminar and transition regimes
Author/Authors :
Garcيa، نويسنده , , A. and Solano، نويسنده , , J.P. and Vicente، نويسنده , , P.G. and Viedma، نويسنده , , A.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
The paper presents an analysis of the flow mechanisms in tubes with wire coils using hydrogen bubble visualization and PIV techniques. Results have been contrasted with experimental data on pressure drop. The relation between the observed flow patterns and the friction factor has been analysed.
perimental analysis that has been carried out allows one to state that at low Reynolds numbers (Re < 400) the flow in tubes with wire coils is basically similar to the flow in smooth tubes. At Reynolds numbers between 500 and 700 and in short pitch wire coils a recirculating flow appears. The insertion of wires coils in a smooth tube accelerates significantly the transition to turbulence. This is produced at Reynolds numbers between 700 and 1000 depending on the wire pitch.
Keywords :
Heat transfer enhancement , Turbulence Promoters , Wire coil inserts , Heat exchangers
Journal title :
International Journal of Heat and Fluid Flow
Journal title :
International Journal of Heat and Fluid Flow