Mass transfer downstream of nozzles in turbulent pipe flow with varying Schmidt number

Abstract

Local mass transfer rates at the wall of a pipe downstream of constricting nozzles have been measured using the electrochemical limiting diffusion current technique for different electrolyte Schmidt numbers. The familiar peaked axial distribution of mass transfer downstream of the nozzle was verified and the peak mass transfer values were found to agree well with the data of Tagget al. [1]. An overall correlation of the data in terms of both Reynolds number and nozzle expansion ratio produced the equation

$$({{Sh_{2P} } \mathord{\left/ {\vphantom {{Sh_{2P} } {Sh_{2FD} }}} \right. \kern-\nulldelimiterspace} {Sh_{2FD} }})({{D_1 } \mathord{\left/ {\vphantom {{D_1 } {D_2 }}} \right. \kern-\nulldelimiterspace} {D_2 }})^{ - 0.7} = 14.39Re_2^{ - 0.182} $$

Limiting current-time traces produced evidence of the highly turbulent flow in the recirculation zone near the position of peak mass transfer.