Optimization of the PGV-1000MKO Steam Generator Using CFD

2020 ◽  
Author(s):  
Vasilii Volkov ◽  
Luka Golibrodo ◽  
Alexey Krutikov ◽  
Oleg Kudryavtsev ◽  
Yurii Nadinskii ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Steam Generator ◽  
Perforated Plate ◽  
Design Sensitivity ◽  
Verification And Validation ◽  
Evaporation Surface ◽  
Reactor Plant ◽  
Uniform Resistance ◽  
Horizontal Steam Generator ◽  
Removal System

Abstract In the VVER -TOI project, new layout solutions were applied in the reactor plant as part of which the steam removal system from the steam generator was changed. Namely, in contrast to the VVER-1000 and VVER-1200 where the steam removal was organized through ten nozzles combined into a steam collector, in the VVER -TOI SG the steam removal was arranged through one nozzle located on the cold collector side. This change leads to the formation of a non-uniform velocity field in the separation volume. To ensure the steam separation characteristics of a horizontal steam generator with one steam nozzle, it was proposed to create a non-uniform resistance on the way of steam motion from the evaporation surface into steam nozzle applying a non-uniform degree of the distribution perforated plate (DPP) perforation. Two computer models of the SG steam volume with different steam removal schemes (one and ten nozzles) were developed, a set of studies on verification and validation was carried out and a set of calculations were performed. Further, to determine the non-uniform degree of DPP perforation, a set of optimization calculations of the SG steam volume with one steam removal nozzle was performed. The non-uniform degree of DPP perforation of the VVER-TOI SG was selected, which provide steam velocity distribution as close as possible to SG with ten steam nozzles. To justify the chosen design, sensitivity analysis was also carried out according to the hole diameters tolerance and steam load profile.

Adjoint Design Sensitivity Analysis of Molecular Gas Film Lubrication Sliders

2002 ◽  
Vol 125 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Sensitivity Analysis ◽  
Design Sensitivity ◽  
Design Sensitivity Analysis ◽  
Finite Difference Approximation ◽  
Molecular Gas ◽  
Air Bearings ◽  
Adjoint Variable ◽  
Topological Parameters ◽  
Molecular Gas Film Lubrication ◽  
Film Lubrication

This paper proposes an analytical design sensitivity analysis (DSA) to topological parameters of MGL (molecular gas film lubrication) sliders by introducing an adjoint variable method. For the analysis of slider air bearings, we used the spatial discretization of the generalized lubrication equation based on a control volume formulation. The residual functions for inverse analysis of the slider are considered as the equality constraint functions. The slider rail heights of all grid cells are chosen as design variables since they are the topological parameters determining air bearing surface (ABS). Then, a complicated adjoint variable equation is formulated to directly handle the highly nonlinear asymmetric coefficient matrix and vector in the discrete system equations of slider air bearings. An alternating direction implicit (ADI) scheme is utilized to efficiently solve large-scale problem in special band storage. The simulation results of DSA are directly compared with those of finite-difference approximation (FDA) to show the effectiveness and accuracy of the proposed approach. The overall sensitivity distribution over the ABS is reported, and clearly shows to which section of the ABS the special attention should be given during the manufacturing process. It is demonstrated that the proposed method can reduce more than 99 percent of the CPU time in comparison with FDA, even though both methods give the same results.

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