Computational fluid dynamics simulations of flow and heat transfer in a preswirl system: influence of rotating-stationary domain interface

J Karnahl, J Von Wolfersdorf, K M Tham, Michael Wilson, Gary Lock

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

This paper presents computational fluid dynamics (CFD) predictions of flow and heat transfer for an over-swirled low-radius preswirl system and comparison with experimental data. The rotor-stator CFD model comprises a stationary domain with the preswirl nozzles and a rotating domain with the receiver holes. The fluid-dynamic conditions feature an over-swirled system with a swirl ratio at the nozzle radius β p 1.4-1.5 and rotational Reynolds number Re Φ 0.8×10 6 and 1.2 10 6. Three different treatments for the rotating and stationary domain interface are used to evaluate the influence on the flow and heat transfer behavior: a stationary approach (including Coriolis forces in the rotating domain) with direct connection and fixed angle between preswirl nozzle and receiver holes; a stationary approach with circumferential averaging of the velocity at radial bands; and a full transient simulation with the rotating domain capturing the unsteady flow due to the rotating receiver holes. Results at different circumferential angles show high variability in pressure and velocity distributions at the preswirl inlet nozzle radius. Circumferential averaging of these flow parameters lead to an alignment of the pressures and velocities between the three different interface approaches. Comparison with experimental pressure and swirl-ratio data show a quantitative agreement but the CFD results feature a systematic overestimation outward of the preswirl nozzle radius. Heat transfer coefficient distributions at the rotor surface show the effect of the different interface approaches and dependence on the flow structure (for example the impinging jet and vortex structures). The three different interface approaches result in significant differences in the computed heat transfer coefficients between pairs of receiver holes. Circumferentially averaged heat transfer coefficients inward of the receiver holes radius show good agreement between the transient and stationary direct connection interfaces, whereas those for the circumferential averaging interface differ, contrary to the flow parameters, due to smoothing of local effects from the preswirl jets.
Original languageEnglish
Article number052502
Number of pages11
JournalJournal of Engineering for Gas Turbines and Power: Transactions of the ASME
Volume134
Issue number5
Early online date21 Feb 2012
DOIs
Publication statusPublished - May 2012

Keywords

  • high variability
  • heat transfer coefficients
  • impinging jet
  • swirl ratio
  • pre-swirl systems
  • local effects
  • rotation
  • heat transfer coefficient distribution
  • Reynolds number
  • computational fluid dynamics simulations
  • circumferential angles
  • CFD models
  • flow and heat transfer
  • pre-swirl
  • connection interface
  • flow parameters
  • nozzles
  • experimental data
  • computational fluid dynamics
  • vortex structures
  • pressure and velocity distributions
  • quantitative agreement
  • nozzle radius
  • inlet nozzles
  • fixed angles
  • transient simulation

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