scholarly journals The Gas-Dynamic Efficiency Increase of the K-300 Series Steam Turbine Control Compartment

2020 ◽  
Vol 23 (4) ◽  
pp. 6-13
Author(s):  
Andrii V. Rusanov ◽  
◽  
Viktor L. Shvetsov ◽  
Anna I. Kosianova ◽  
Yurii A. Bykov ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Dynamic Efficiency ◽  
Navier Stokes Equations ◽  
Gas Dynamic ◽  
Operation Modes ◽  
Flow Part ◽  
Object Of Study ◽  
Control Compartment

The paper proposes ways to increase the efficiency of nozzle control for steam power turbines of the K-300 series, that, along with the K-200 series turbines, form the basis of thermal energy in Ukraine. The object of study is considered to be the control compartment (CC) of the high-pressure cylinder (HPC) of the K-325-23.5 steam turbine. In the paper, the calculation and design of the control compartment of the steam turbine was performed using the complex methodology developed in IPMach NAS of Ukraine, that includes methods of different levels of complexity, from one-dimensional to models for calculation of spatial viscous flows, as well as analytical methods for spatial geometries of flow parts description based on limited number of parameterized values. The complex design methodology is implemented in the IPMFlow software package, which is a development of the FlowER and FlowER–U software packages. A model of a viscous turbulent flow is based on the numerical integration of an averaged system of Navier-Stokes equations, for the closure of which the two-term Tamman equation of state is used. Turbulent phenomena were taken into account using a SST Menter two-parameter differential turbulence model. The research was conducted for six operation modes in the calculation area, which consisted of more than 3 million cells (elementary volumes), taking into account the interdiscand diaphragm leakage. According to the results of numerical studies of the original control compartment of the K-325-23.5 steam turbine, it is shown that the efficiency in the flow part is quite low in all operation modes, including the nominal one (100% power mode), due to large losses of kinetic energy in the equalization chamber, as well as inflated load on the first stage. On the basis of the performed analysis of gas-dynamic processes, the directions of a control compartment flow part modernization are formed and themodernization itself is executed. In the new flow part, compared to the original one, there is a favorable picture of the flow in all operation modes, which ensures its high gas-dynamic efficiency. Depending on the mode, the efficiency of the control compartment increased by 4.9–7.3%, and the capacity increased by 1–2 MW. In the nominal mode (100% mode) the efficiency of the new control compartment, taking into account the interdisc and overbandage leakage, is 91%.

scholarly journals PARALLEL COMPUTATIONS IN STUDIES OF DEPENDENCE OF GAS DYNAMIC PARAMETERS OF UPWARD SWIRLING FLOW OF GAS ON BLOWING VELOCITY

2016 ◽  
pp. 92-97
Author(s):  
R. E. Volkov ◽  
A. G. Obukhov
Keyword(s):  
Stokes Equations ◽  
Swirling Flow ◽  
Initial Conditions ◽  
Exact Analytical Solution ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Computational Domain ◽  
Navier Stokes Equations ◽  
Gas Dynamic

The rectangular parallelepiped explicit difference schemes for the numerical solution of the complete built system of Navier-Stokes equations. These solutions describe the three-dimensional flow of a compressible viscous heat-conducting gas in a rising swirling flows, provided the forces of gravity and Coriolis. This assumes constancy of the coefficient of viscosity and thermal conductivity. The initial conditions are the features that are the exact analytical solution of the complete Navier-Stokes equations. Propose specific boundary conditions under which the upward flow of gas is modeled by blowing through the square hole in the upper surface of the computational domain. A variant of parallelization algorithm for calculating gas dynamic and energy characteristics. The results of calculations of gasdynamic parameters dependency on the speed of the vertical blowing by the time the flow of a steady state flow.

GENERALIZED GAS DYNAMIC EQUATIONS WITH MULTIPLE TRANSLATIONAL TEMPERATURES

2009 ◽  
Vol 23 (03) ◽  
pp. 237-240 ◽  
Author(s):  
KUN XU ◽  
ZHAOLI GUO
Keyword(s):  
Flow Regime ◽  
Stokes Equations ◽  
Dimensional Space ◽  
Natural Extension ◽  
Dynamic Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Gas Dynamic ◽  
Continuum Flow ◽  
Gas Dynamic Equations

Based on a multiple stage BGK-type collision model and the Chapman–Enskog expansion, the corresponding macroscopic gas dynamics equations in three-dimensional space will be derived. The new gas dynamic equations have the same structure as the Navier–Stokes equations, but the stress strain relationship in the Navier–Stokes equations is replaced by an algebraic equation with temperature differences. In the continuum flow regime, the new gas dynamic equations automatically recover the standard Navier–Stokes equations. The current gas dynamic equations are natural extension of the Navier–Stokes equations to the near continuum flow regime and can be used for near continuum flow study.

scholarly journals INVESTIGATION OF GAS-DYNAMIC PROCESSES IN PIPELINE COMMUNICATIONS DURING THEIR TRENCHLESS RECONSTRUCTION WITH THE TECHNOLOGY "TRACTION PISTON"

2019 ◽  
pp. 43-53
Author(s):  
K. A. Poliarush
Keyword(s):  
Stokes Equations ◽  
Air Flow ◽  
Longitudinal Section ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Dynamic Processes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Software Complex ◽  
Gas Dynamic

The technology of the trenchless reconstruction of pipeline communications "Traction Piston", which consists in running a new polyethylene pipeline into a steel one worn by pigis described. At the same time, in order to maintain the necessary pressure in the cavity, the space between the new polyethylene pipeline and the worn steel one is sealed. A 3D modeling of the annulus and space behind the piston, where the complex turbulent flow of air flows, is carried out. A CFD modeling of gas-dynamic processes in the annulus and space behind the piston while laying a worn steel pipeline with a polyethylene pipeline in the ANSYS Fluent software system is performed. The mathematical model is based on the solution of the Navier-Stokes equations and the continuity of the flow closed by a two-parameter turbulence model of Launder-Sharma with the use of a wall function with corresponding initial and boundary conditions. A dynamic grid model was used to simulate the motion of the piston and the polyethylene pipeline. The type of adjustment of the dynamic grid parameters during the stroke of a new polyethylene pipeline into a defective steel one – Layering was chosen. The simulation results were visualized in the postprocessor of the software complex by constructing flow lines, velocity vectors, pressure fields on the contours and in the longitudinal section of the annulus and space behind the piston. The exact values of velocity, pressure at different points between the annulus and space behind the piston were determined. The structure of the air flow in the cavity and interstitial space is studied. The places of slowdown and acceleration of air flow, falling and increase of pressure are found. The loss of pressure in the annular space is determined.

scholarly journals ACCOUNTING INFLUENCE OF CENTRIFUGAL FORCE IN THE NUMERICAL MODELING OF RISING SWIRLED GAS FLOW

2015 ◽  
pp. 92-97
Author(s):  
S. P. Bautin ◽  
A. G. Obukhov
Keyword(s):  
Centrifugal Force ◽  
Gas Flow ◽  
Stokes Equations ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Navier Stokes Equations ◽  
Power Characteristics ◽  
Gas Dynamic

In work the consistent inclusion of centrifugal force in the numerical calculations of three-dimensional gas-dynamic characteristics of the unsteady flow of compressible viscous heat-conducting gas in an upward swirling flow caused by the vertical cold blowing. Provides detailed conversion of the complete system of Navier-Stokes equations associated with consistent view of the centrifugal force. Results of thermodynamic calculations and comparisons, speed and power characteristics of emerging upward swirling flows. There was a slight influence of the centrifugal force on the basic parameters of the gas-dynamic study of complex flows of gas.

Numerical Model of Liquid Film Formation and Breakup in Last Stage of a Low-Pressure Steam Turbine

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Pietro Rossi ◽  
Asad Raheem ◽  
Reza S. Abhari
Keyword(s):  
Steam Turbine ◽  
Stokes Equations ◽  
Low Pressure ◽  
Liquid Films ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Last Stage ◽  
The Impact

Formation of thin liquid films on steam turbine airfoils, particularly in last stages of low-pressure (LP) steam turbines, and their breakup into coarse droplets is of paramount importance to assess erosion of last stage rotor blades given by the impact of those droplets. An approach for this problem is presented in this paper: this includes deposition of liquid water mass and momentum, film mass and momentum conservation, trailing edge breakup and droplets Lagrangian tracking accounting for inertia and drag. The use of thickness-averaged two-dimensional (2D) equations in local body-fitted coordinates, derived from Navier–Stokes equations, makes the approach suitable for arbitrary curved blades and integration with three-dimensional (3D) computational fluid dynamics (CFD) simulations. The model is implemented in the in-house solver MULTI3, which uses Reynolds-averaged Navier–Stokes equations κ – ω model and steam tables for the steam phase and was previously modified to run on multi-GPU architecture. The method is applied to the last stage of a steam turbine in full and part load operating conditions to validate the model by comparison with time-averaged data from experiments conducted in the same conditions. Droplets impact pattern on rotor blades is also predicted and shown.

scholarly journals Adaptive Time-Stepping for Incompressible Flow Part II: Navier–Stokes Equations

2010 ◽  
Vol 32 (1) ◽  
pp. 111-128 ◽  
Author(s):  
David A. Kay ◽  
Philip M. Gresho ◽  
David F. Griffiths ◽  
David J. Silvester
Keyword(s):  
Incompressible Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Time Stepping ◽  
Flow Part ◽  
Adaptive Time ◽  
Adaptive Time Stepping

Numerical Estimation of Losses in Steam Flow Through LP Turbine Stages

2005 ◽  
Author(s):  
Slawomir Dykas ◽  
Wlodzimierz Wroblewski
Keyword(s):  
Steam Turbine ◽  
Stokes Equations ◽  
Turbine Rotor ◽  
Steam Flow ◽  
Navier Stokes ◽  
Meridional Plane ◽  
Navier Stokes Equations ◽  
Streamline Curvature ◽  
Flow Through ◽  
Lp Turbine

The aim of this work is to estimate the losses in the steam flow through the LP steam turbine rotor and the whole stage. For steam flow two types of losses take place, aerodynamic (profile, secondary flow, leakage) and thermodynamic (due to the heat addition caused by condensation). Presented numerical results are split into two groups. In the first part of this work the comparison of the three different calculation methods of steam flow is carried out. To this end the geometry of LP steam turbine last rotor is chosen. The first method is a Streamline Curvature Method (SCM) used on the meridional plane with losses correlations, and the next two methods, commercial and an in-house CFD codes, solve the Reynolds averaged Navier-Stokes equations for a 3-D flow. Below the saturation line the first two codes model equilibrium steam properties, and the last one models non-equilibrium steam properties. Then for the geometry of the penultimate stage, with the use of an in-house CFD code, the comparison of the different types of condensation models on the losses prediction is examined.

Influence of Compound Lean on an Industrial Steam Turbine Stage

2015 ◽  
Author(s):  
Srikanth Deshpande ◽  
Marcus Thern ◽  
Magnus Genrup
Keyword(s):  
Steam Turbine ◽  
Pressure Loss ◽  
Total Pressure ◽  
Stokes Equations ◽  
Tangential Direction ◽  
Total Pressure Loss ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Navier Stokes Equations ◽  
Commercial Code

Compound lean implemented on stator of an industrial steam turbine stage in order to reduce secondary losses are discussed. Baseline stator is a prismatic vane with aspect ratio of unity. Compound lean stator blade is designed by shearing the airfoil sections in tangential direction. Modifications are analyzed numerically using commercial code CFX. Three blade rows i.e. one complete stage with a downstream stator are analyzed. Steady state Reynolds averaged Navier Stokes equations are solved. Total pressure loss (TPL) is used as objective function to monitor reduction in secondary losses. Rotor is retained the same for baseline as well as compound leaned stator. Results show reduction in total pressure loss of stator in excess of 5 %. Also, computations of co-efficient of secondary kinetic energy shows significant reduction in secondary losses in excess of 30 % in stator. Efficiency gained by implementation of compound lean are discussed.

Vortexing Methods to Reduce Secondary Losses in a Low Reaction Industrial Turbine

2015 ◽  
Author(s):  
Srikanth Deshpande ◽  
Marcus Thern ◽  
Magnus Genrup
Keyword(s):  
Steady State ◽  
Steam Turbine ◽  
Pressure Loss ◽  
Total Pressure ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Blade Design ◽  
Navier Stokes Equations ◽  
Commercial Code ◽  
Turbine Vane

Vortexing methods implemented on an industrial steam turbine vane in order to reduce secondary losses are discussed. Three vortexing methods presented are prismatic blade design, inverse vortex and parabolic forced vortex. Baseline industrial vane considered for study is a prismatic blade design. Modifications are analysed numerically using commercial code CFX. Modified vanes along with baseline rotor as a complete stage is considered for analysis. Steady state Reynolds averaged Navier Stokes equations are solved. Total pressure loss (TPL) is used as target functions to monitor reduction in secondary losses. Rotor considered for the study is the baseline industrial rotor for all design modifications of vane.

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