Drag reduction of flow boiling with polymer additives

Abstract

The drag-reducing effect of polymer additive aqueous solution was investigated in flow boliling, and the polymer additives were two kinds of polyacrylamide (PAM) with relative molecular mass about 2.56×10⁶ and 8.55×10⁶. The frictional pressure drop was calculated according to the measured total pressure drop. The results show that the flow drag of flow boiling is reduced by adding a small amount of PAM to water when heat flux is in the range of 15.1 kW·m⁻² to 47.0 kW·m⁻², when the mass fraction of PAM is higher than 2.0×10⁻⁵, the drag-reducing effect is obvious. Drag-reducing effect of PAM, whose relative molecular mass is 8.55×10⁶, is slightly better than that of 2.56×10⁶ at the same mass fraction, and the greater the flow rate of the additive solution, the better the effect of the drag reduction.

Keywords

polymer additive / flow boiling / drag reduction / pressure drop

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