Wet steam energy loss and related Baumann rule in low pressure steam turbines

Abstract

This paper presents the results of a computational analysis of the wet steam energy loss occurring in a 210 MW fossilfired and a 1000 MW nuclear LP steam turbine. The turbines operate under considerably different conditions as regards pressure level in the droplet nucleation zone, exit moisture level and droplet size spectra determined from optical extinction measurements. An evaluation of the basic wetness energy losses has been carried out including the thermodynamic loss, drag loss of the fine and coarse droplets, impact loss, collected water loss, centrifuging loss and exit loss. A statistical 2D evaluation method has been employed for the computational simulation of the loss. The objective of the analysis was to determine whether an equilibrium based Baumann factor of order 0.6 can be used for predicting the wet steam loss.

Water Mixtures as Working Fluids in Organic Rankine Cycles

“…Thanks to the high molecular complexity of 2-methylpyrazine (see Table 1), the dew line of the water mixture at z 0 1 = 0.5, in Figure 5b, was almost isentropic, avoiding liquid formation during fluid expansion even without superheating. This leads to no blade erosion issues due to the dry expansion [50,51]. Moreover, the medium molecular complexity with respect to siloxanes or other organic fluid (σ > 15-20) allows adopting a simple cycle configuration instead of the typical regenerative one used.…”

A 3D method to evaluate moisture losses in a low pressure steam turbine: Application to a last stage

“…Starzmann et al [7] made a tentative prediction of the moisture losses in a three-stage model low pressure steam turbine by a 3D two-phase CFD modeling, but only thermodynamic loss, kinematic and braking losses were considered. Petr and Kolovratnik [8] employed a statistical two-dimensional (2D) evaluation method to compute the moisture losses based on the 3D computational flow-field in a 1000 MW nuclear and a 210 MW fossil-fired low pressure steam turbine.…”

Experimental research of heterogeneous nuclei in superheated steam

“…The requirement of efficiency and reliability enhancements also affects the steam turbine as an important part of the Rankine cycle of thermal power plants. In the lowpressure part (LP) of the steam turbine, the steam undergoes the process of nucleation and condensation into primary droplets [1]. Some of the primary droplets hit the blades and other surfaces and form a liquid film.…”