scholarly journals Numerical Simulation of Non-Equilibrium Two-Phase Wet Steam Flow through an Asymmetric Nozzle

Fluids ◽  
2017 ◽  
Vol 2 (4) ◽  
pp. 63
Author(s):  
Miah Alam ◽  
Manabu Takao ◽  
Toshiaki Setoguchi
Keyword(s):  
Numerical Simulation ◽  
Steam Flow ◽  
Wet Steam ◽  
Two Phase ◽  
Flow Through ◽  
Wet Steam Flow ◽  
Non Equilibrium

Numerical Solution of Wet Steam Flow through Blade Cascade

2016 ◽  
Vol 821 ◽  
pp. 31-38
Author(s):  
Vladimír Hric ◽  
Jan Halama
Keyword(s):  
Equations Of State ◽  
Suction Side ◽  
Steam Flow ◽  
Droplet Growth ◽  
Wet Steam ◽  
Two Phase ◽  
Blade Cascade ◽  
Flow Through ◽  
Wet Steam Flow ◽  
Non Equilibrium

The paper concerns with the numerical modeling of wet steam flow through a blade cascade in transonic regime with non-equilibrium condensation in 2D. Real thermodynamics of vapor phase is implemented in the way which mostly avoid iterations in order to calculate thermodynamic properties. This equation of state is represented by the function for non-dimensional entropy with independent variables scaled density and scaled internal energy. Other equations of state are used for comparison, namely special gas equation which comes from IAPWS-95 formulation and simple pseudo perfect gas relation. We applied simple homogeneous non-equilibrium approach to model two-phase flow. Laminar compressible Navier-Stokes system of equations is used for the mixture properties. Liquid phase is described by the standard method of moments of droplet number distribution function. We consider obtained numerical results to be in good agreement with the measured data. We note the fact that robust and accurate closure of supplementary liquid system (nucleation rate and droplet growth model) is still not available and most often ad-hoc corrections are proposed by the authors. Results show differences among used equations of state as well. This is apparent mainly in the vicinity of condensation shock region on the suction side.

Non-equilibrium condensation of wet steam flow within high-pressure thermo-compressor

2015 ◽  
Vol 81 ◽  
pp. 74-82 ◽  
Author(s):  
S.M.A. Noori Rahim Abadi ◽  
R. Kouhikamali ◽  
K. Atashkari
Keyword(s):  
High Pressure ◽  
Steam Flow ◽  
Wet Steam ◽  
Wet Steam Flow ◽  
Non Equilibrium

Losses estimation in transonic wet steam flow through linear blade cascade

2015 ◽  
Vol 24 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Sławomir Dykas ◽  
Mirosław Majkut ◽  
Michał Strozik ◽  
Krystian Smołka
Keyword(s):  
Steam Flow ◽  
Wet Steam ◽  
Blade Cascade ◽  
Flow Through ◽  
Wet Steam Flow

The Effects of Water Injections in Wet Steam Flow in Different Regions of a Mini Laval Nozzle

2008 ◽  
Author(s):  
M. R. Mahpeykar ◽  
E. Amirirad ◽  
E. Lakzian
Keyword(s):  
Nucleation Rate ◽  
Laval Nozzle ◽  
Pressure Rise ◽  
Steam Flow ◽  
Steam Turbines ◽  
Wet Steam ◽  
Water Droplets ◽  
Two Phase ◽  
Condensation Shock ◽  
Wet Steam Flow

Progress in the development of the steam turbines brings about a renewal of interest in wetness associated problems. In turbine steam expansion, the vapour first supercools and then condenses spontaneously to become a two phase mixture. The flow initially is single phase but after Wilson point water droplets are developed and there is a non equilibrium two phase flow. The formation and behavior of the liquid create problems that lower the performance of the turbine wet stage and the mechanisms underlying this are insufficiently understood. This growing droplets release their latent heat to the flow and this heat addition to the supersonic flow cause a pressure rise called condensation shock. Because of irreversible heat transfer in this region the entropy will increase tremendously. Removal of condensates from wet steam flow in the last stage of steam turbines significantly promotes stage efficiency and prevents erosion of rotors. The following study investigates the spraying water droplets at inlet and at throat of mini Laval nozzle and their effects on nucleation rate and condensation shock. According to the results, the nucleation rate is considerably suppressed and therefore the condensation shock nearly disappeared. In other words the injecting droplets would decrease the thermodynamic losses or improve the turbine efficiency.

Numerical Investigation of Two-Phase Wet Steam Flow With Spontaneous Condensation Based on Euler S2 Calculation Method

2015 ◽  
Author(s):  
Deying Li ◽  
Huanlong Chen ◽  
Yanping Song ◽  
Ke Cui ◽  
Hiroharu Ooyama
Keyword(s):  
Coordinate System ◽  
Calculation Method ◽  
Steam Flow ◽  
Wet Steam ◽  
Two Phase ◽  
Stream Surface ◽  
Spontaneous Condensation ◽  
Wet Steam Flow ◽  
Pressure Nozzle ◽  
Surface Calculation

The Euler equation suitable for the S2 stream surface calculation is derived in the arbitrary orthogonal coordinate system firstly. The numerical method for the two-phase wet steam flow with the spontaneous condensation is then developed on basis of the Euler S2 calculation code, the Eulerian/Eulerian multiphase model and the classic nucleation theory. To adapt the complex geometry of the turbine blades, the Euler equations for the S2 stream surface calculation method are derived in the body-fitted coordinate system. The mathematical model for the third order TVD scheme with the non-conservative variables is also developed for the gas phase governing equation. The 2nd order NND and the VanLeer scheme are applied to the variable reconstruction and the numerical flux calculation respectively in the liquid equations solving process. The pressure and the droplet radii distribution fit well with the experimental data for both the high pressure nozzle and the low pressure nozzle. The S2 calculation method is also employed to predict the performance of a 3-stage low pressure steam turbine with spontaneous steam condensation, and the reasonable results are obtained. The numerical method developed in the present work is able to predict the real wet steam flow with the spontaneous condensation and its impact on the flow field and the aerodynamic parameters distribution reasonably, supplying a fast and accurate technic and method to the steam turbine design.

Eulerian-Lagrangian Numerical Simulation of Wet Steam Flow Through Multi-Stage Steam Turbine

2013 ◽  
Author(s):  
Yasuhiro Sasao ◽  
Satoshi Miyake ◽  
Kenji Okazaki ◽  
Satoru Yamamoto ◽  
Hiroharu Ooyama
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Steam Flow ◽  
Droplet Growth ◽  
Computational Domain ◽  
Steam Turbines ◽  
Wet Steam ◽  
Multi Stage ◽  
Flow Through ◽  
Wet Steam Flow

In this paper, we present an inclusive tracking algorithm for water droplets in a wet steam flow through a multi-stage steam turbine. This algorism is based on the Eulerian-Lagrangian coupled solver. The solver continuously computes water droplet growth, kinematic non-equilibrium between vapor and droplets, capture and kinetics of droplets on turbine blades, departure of large droplets from the trailing edge of blades, acceleration and atomization of large droplets, and recollisions between blades and droplets. Our Eulerian-Lagrangian coupled solver is used to predict wetness in unsteady three-dimensional (3D) wet steam flows through three-stage stator rotor cascade channels in a low pressure (LP) steam turbine model which is developed by Mitsubishi Heavy Industries (MHI). Droplet groups tracked by the discrete droplet model (DDM) are placed in the computational domain according to the predicted wetness. Interference from the gas phase on the droplets is considered, to track their kinetic and behavior, until they reach the outlet of the computational domain. The aim of this research is to investigate those multi-physics phenomena that trigger all forms of loss in steam turbines. In addition, this method will also be applied to multi-physics problems such as erosion in future work. This paper is presented as a first step in the research. Overviews of model of current coupling solver and several test calculations are presented.

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