Investigation of swirl pipe for improving cleaning efficiency in closed processing system

  • Guozhen LI

Student thesis: PhD Thesis


This thesis provides unique insights into the fundamentals of improving the efficiency of ‘Clean-In-Place’ procedures in closed processing systems by locally introducing intensified hydrodynamic force from swirl flows induced by an optimised four-lobed swirl pipe without increasing the overall flow velocities. The studies, carried out employing Computational Fluid Dynamics (CFD) techniques, pressure transmitters and a fast response Constant Temperature Anemometer (CTA) system, covered further optimisation of the four-lobed swirl pipe, RANS-based modelling and Large Eddy Simulation of the swirl flows, and experimental validation of the CFD models through the measurements of pressure drop and wall shear stress in swirl flows with various Reynolds Number. The computational and experimental work showed that the swirl pipe gives rise to a clear increase of mean wall shear stress to the downstream with its value and variation trend being dependent on swirl intensity. Moreover, it promotes a stronger fluctuation rate of wall shear stress to the downstream especially further downstream where swirl effect is less dominant. As the increase of either the mean or the fluctuation rates of wall shear stress contributes to the improvement of CIP procedures in the closed processing systems. This thesis demonstrates that, with the ability to exert strengthened hydrodynamic force to the internal surface of the pipe downstream of it without increasing the overall flow velocity, the introduction of swirl pipe to the CIP procedures should improve the cleaning efficiency in the closed processing systems, consequently shortening the downtime for cleaning, and reducing the costs for chemicals and power energy.
Date of Award3 Jun 2016
Original languageEnglish
Awarding Institution
  • Univerisity of Nottingham
SupervisorPhilip Hall (Supervisor) & Nick Miles (Supervisor)


  • Swirl pipe
  • Clean-In-Place
  • Wall shear stress
  • CFD
  • Large Eddy Simulation
  • hot-film Anemometry

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