A laboratory study was performed to characterize the supersonic jet-tube interactions that occur in kraft recovery boiler superheater, generating bank, and economizer sections during sootblowing. For the first time, such interactions were visuahzed using the schheren technique coupled with high-speed video, and quantified by pitot pressure measurements. Results showed that upon impingement on a tube, a supersonic jet deflects at an angle, forming a weaker secondary jet. Due to a relatively small core length, this jet cannot impinge on an adjacent superheater platen with a significant impact pressure. However, due to the closer tube spacing in the generating bank and economizer, secondary jets impinge on the tubes in the adjacent rows, and may help remove deposits in these regions. Due to its narrow spreading angle, a sootblower jet must be directed close to superheater platens to yield useful jet-deposit interactions. While a jet between superheater platens may propagate unaffected, a jet between generating bank tubes is weakened because of interaction with tubes and increased mixing. A jet between finned economizer tubes decays more quickly than a free jet, but is stronger than the same jet in the generating bank because the fins restrict the spreading of the jet.
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