Improvements of Experimental Research of Wet Steam in Turbines Using CFD Simulations

2020 ◽  
Author(s):  
Michal Kolovratnik ◽  
Gukchol Jun
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Experimental Research ◽  
Phase Structure ◽  
Influence Factor ◽  
Optical Probe ◽  
Steam Turbines ◽  
Wet Steam ◽  
Cfd Simulations ◽  
Optical Extinction

Abstract The Czech Technical University in Prague (CTU) has been conducting both theoretical and experimental research on wet steam for over 50 years. Part of this research has focused on the development of an instrument for measuring the structure of the liquid phase of wet steam — an optical extinction probe. The measurements of the wet steam structure using our optical extinction probe take place in operative steam turbines. Due to the non-negligible interaction of the probe with the flow field in its vicinity, the wet steam parameters within the probe measuring space change. This probe-flow field interaction (PFFI) negatively affects the accuracy of the measurement of the liquid phase structure. This paper presents partial results of our research into the interaction between the optical probe and the surrounding flow field. Particularly, it is the result of CFD simulations of wet steam (WS) flow in the low-pressure section of a 1000 MW nuclear plant steam turbine, in which the probe has been used repeatedly. In the simulations we consider, non-equilibrium condensation allows for the observation of the formation and development of the liquid phase within the turbine. The influence of PFFI on the liquid phase structure is evaluated by a coefficient called the Probe Influence Factor (PIF). In this work, the PIF values are presented for 3 varying traversing positions of the probe along the L-1 stage turbine blade. The use of the PIF to analyse the experimental measurement results is also discussed. The second part of the paper deals with the possibility of modifying the shape of the probe measuring head. Based on detailed analysis of the CFD simulations of PFFI, modifying the shape of the probe is proposed to reduce this interaction. The benefit of this change is evaluated using CFD simulations. Comparisons between the PIF coefficients of the original and modified optical probes indicate that modifying the shape may reduce the PFFI influence on experimental measurements.

scholarly journals CFD analysis of optical probe interaction with wet steam flow field

2018 ◽  
Vol 180 ◽  
pp. 02045 ◽  
Author(s):  
Michal Kolovratník ◽  
Gukchol Jun ◽  
Ondřej Bartoš
Keyword(s):  
Flow Field ◽  
High Pressures ◽  
Optical Probe ◽  
Steam Flow ◽  
Steam Turbines ◽  
Wet Steam ◽  
Water Steam ◽  
Flow Geometry ◽  
Phase Size ◽  
Wet Steam Flow

In the frame of the measurement feasibility study of the liquid phase size distribution structure in steam turbines at intermediate and high pressures, on CTU the interaction of optical probes with the wet steam flow field is investigated. In order to validate and refine the existing knowledge, a new series of CFD simulations were performed, considering turbine flow geometry, water steam characteristics according to IAPWS97 formulation, and improved boundary conditions and quality of the computing mesh. This paper briefly presents the newly obtained results

scholarly journals A study of the electrostatic charge of the coarse water droplets

2021 ◽  
Vol 345 ◽  
pp. 00003
Author(s):  
Ondřej Bartoš ◽  
Václav Peter
Keyword(s):  
Liquid Phase ◽  
Wind Tunnel ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Electrical Current ◽  
Electrostatic Charge ◽  
Steam Turbines ◽  
Wet Steam ◽  
Water Droplets ◽  
Charging Mechanism

The aim of this paper is introduce the results of a measurement of the electrostatic charge of water droplets during wet steam expansion. The analysis of the charge origin was done. The achieved result shows that there is not a significant charging mechanism for the fine droplets. The dependence between the specific electrical current and the amount of liquid phase collected by the probe was found. Some models were studied to determine the origin of the electrical current. Finally a model was proposed, where the el. current is generated by the disruption of thin liquid film on the surface of the probe. The charging model was later applied for the measurement of the liquid film disruption in the new wind tunnel designed for the simulation of the flow field in the steam turbines. The measurement was performed with the air as a flowing medium and two modal droplets size distribution was found.

scholarly journals Influence of a Standing Wave Flow-Field on the Dynamics of a Spray Diffusion Flame

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
J. Barry Greenberg ◽  
David Katoshevski
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Standing Wave ◽  
Diffusion Flame ◽  
Stokes Number ◽  
Flame Height ◽  
Wave Flow ◽  
Two Dimensional ◽  
Governing Equations ◽  
First Time

A theoretical investigation of the influence of a standing wave flow-field on the dynamics of a laminar two-dimensional spray diffusion flame is presented for the first time. The mathematical analysis permits mild slip between the droplets and their host surroundings. For the liquid phase, the use of a small Stokes number as the perturbation parameater enables a solution of the governing equations to be developed. Influence of the standing wave flow-field on droplet grouping is described by a specially constructed modification of the vaporization Damkohler number. Instantaneous flame front shapes are found via a solution for the usual Schwab–Zeldovitch parameter. Numerical results obtained from the analytical solution uncover the strong bearing that droplet grouping, induced by the standing wave flow-field, can have on flame height, shape, and type (over- or under-ventilated) and on the existence of multiple flame fronts.

scholarly journals Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Experimental Research ◽  
Separation Efficiency ◽  
Structural Parameters ◽  
Separation Performance ◽  
Insertion Depth ◽  
Flow Field Characteristics ◽  
Vortex Finder ◽  
Fine Classification

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.

A fast response miniature probe for wet steam flow field measurements

2016 ◽  
Vol 27 (12) ◽  
pp. 125901
Author(s):  
Ilias Bosdas ◽  
Michel Mansour ◽  
Anestis I Kalfas ◽  
Reza S Abhari
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Fast Response ◽  
Steam Flow ◽  
Wet Steam ◽  
Wet Steam Flow

On the performance of a cascade of turbine rotor tip section blading in wet steam Part 3: Wake traverses

1997 ◽  
Vol 211 (8) ◽  
pp. 639-648 ◽  
Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
O C Jadayel
Keyword(s):  
Liquid Phase ◽  
Two Phase Flow ◽  
Turbine Rotor ◽  
Phase Flow ◽  
Wet Steam ◽  
Flow Conditions ◽  
Two Phase ◽  
Blow Down ◽  
The Third ◽  
Phase Mixture

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. The liquid phase consists of a large number of extremely small droplets which are difficult to generate except by nucleation. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the third of a set describing an investigation into the performance of a cascade of rotor tip section profiles in wet steam and presents the results of the wake traverses.

Experimental Research on Bonding Intensity of Iron Ores in the Sintering Process

2011 ◽  
Vol 391-392 ◽  
pp. 60-64
Author(s):  
Fang Yi Long ◽  
Sheng Li Wu ◽  
Juan Zhu ◽  
Yuan Du ◽  
Guo Liang Zhang
Keyword(s):  
South Africa ◽  
Liquid Phase ◽  
Experimental Research ◽  
Negative Correlation ◽  
Influence Factors ◽  
Iron Ores ◽  
Sintering Process ◽  
Different Types ◽  
Lower Porosity

The bonding intensity of four kinds of ores from Brazil, Australia and South Africa is researched in this study, and the influence factors are analyzed. The results show that, the ores of different types have apparently differences in bonding intensity, ores from Brazil and South Africa have high bonding intensity, while ores from Australia have low bonding intensity; The foundation of generation of effective liquid is adequate liquid phase fluidity and the lower porosity of core ore; The ratio of porosity of core ore and the index of liquid phase fluidity has negative correlation with the bonding intensity.

scholarly journals Experimental research on flow field of high head pump turbine based on PIV test

2021 ◽  
Vol 627 ◽  
pp. 012016
Author(s):  
D M Liu ◽  
L B Ma ◽  
N Li ◽  
Y Z Zhao ◽  
Huan Cheng
Keyword(s):  
Flow Field ◽  
Experimental Research ◽  
Pump Turbine ◽  
High Head

Numerical Analysis of Swirl Control Strategies in a Four Valve HSDI Diesel Engine

2004 ◽  
Author(s):  
S. Fontanesi ◽  
E. Mattarelli ◽  
L. Montorsi
Keyword(s):  
Flow Field ◽  
Control Strategies ◽  
Cfd Simulations ◽  
Full Load ◽  
Partial Load ◽  
Swirl Intensity ◽  
Port Design ◽  
Current Production ◽  
Hsdi Diesel Engine ◽  
Cylinder Flow

Recent four value HSDI Diesel engines are able to control the swirl intensity, in order to enhance the in-cylinder flow field at partial load without decreasing breathing capabilities at full load. Making reference to a current production engine, the purpose of this paper is to envestiage the influence of port design and flow-control strategies on both engine permeability and in-cylinder flow field. Using previously validated models, 3-D CFD simulations of the intake and compression strokes are performed in order to predict the in-cylinder flow patterns originated by the different configurations. The comparison between the two configurations in terms of airflow at full load indicates that Geometry 2 can trap 3.03% more air than Geometry 1, while the swirl intensity at IVC is reduced (−30%). The closure of one intake valve (the left one) is very effective to enhance the swirl intensity at partial load: the Swirl Ratio at IVC passes from 0.7 to 2.6 for Geometry 1, while for Geometry 2 it varies from 0.4 to 2.9.

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