Title: Nucleation of droplets and homogeneous condensation in an LP-steam turbine

Authors: Dieter E. Bohn, Husnu Kerpicci

Addresses: Institute of Steam and Gas Turbines, Aachen University of Technology, Templergraben 55, 52056 Aachen, Germany. Institute of Steam and Gas Turbines, Aachen University of Technology, Templergraben 55, 52056 Aachen, Germany

Abstract: During expansion of steam in steam turbines, after crossing the saturation line, nucleation of droplets starts spontaneously in the main steam flow. This two-phase wet-steam mixture, containing a very large number of extremely small droplets, causes thermodynamic as well as aerodynamic losses in low-pressure (LP) steam turbines. This paper describes 3D two-phase calculations in a nozzle guide vane of a LP-steam turbine. Non-equilibrium nucleation and growth calculations are performed in a Lagrangian approach. The Eulerian calculation technique is applied for the continuum vapour phase. The main flow field is considered as inviscid. Computations are performed in a pressure-correction calculation algorithm. In order to improve understanding of condensation in LP-steam turbines and to admit secondary flow phenomena in the near future, 3D flow effects on the nucleation of droplets are analysed in this study. Computations of accurate droplet trajectories are also presented.

Keywords: condensation; Lagrangian/Eulerian approach; nucleation; wet-steam flow.

DOI: 10.1504/PCFD.2001.001481

Progress in Computational Fluid Dynamics, An International Journal, 2001 Vol.1 No.4, pp.169-177

Published online: 04 Jul 2003 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article