The fundamental hydrodynamics of sootblower nozzles and jets are exami
ned. For currently available nozzles, a substantial fraction of the en
ergy available in the steam jet is dissipated as the steam passes thro
ugh a shock wave only a few jet diameters beyond the nozzle outlet. On
ly a small fraction of the initial energy is delivered to the heat-tra
nsfer surface for cleaning. Efforts to increase the delivered energy b
y raising the upstream steam pressure above the design condition produ
ces a larger shock wave and only a small increase in delivered energy.
Nozzle design should be changed to permit full expansion of the steam
before it leaves the nozzle. This would eliminate the shock wave and
substantially improve sootblower performance.