A blackbox optimization of volumetric heating rate for reducing the wetness of the steam flow through turbine blades

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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On the application of isogeometric finite volume method in numerical analysis of wet-steam flow through turbine cascades

Computers & Mathematics with Applications ◽

10.1016/j.camwa.2019.09.025 ◽

2020 ◽

Vol 79 (6) ◽

pp. 1687-1705 ◽

Cited By ~ 3

Author(s):

Ali Hashemian ◽

Esmail Lakzian ◽

Amir Ebrahimi-Fizik

Keyword(s):

Numerical Analysis ◽

Finite Volume Method ◽

Finite Volume ◽

Steam Flow ◽

Wet Steam ◽

Flow Through ◽

Turbine Cascades ◽

Wet Steam Flow ◽

Volume Method

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Part II. Research on the Performance of a Type of Internally Air-cooled Turbine Blade

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1953_167_040_02 ◽

1953 ◽

Vol 167 (1) ◽

pp. 351-370 ◽

Cited By ~ 6

Author(s):

D. G. Ainley

Keyword(s):

Gas Flow ◽

Thermal Stresses ◽

Turbine Blades ◽

Small Diameter ◽

Rotor Blades ◽

Air Cooling ◽

Gas Temperature ◽

Flow Through ◽

Cooling Air ◽

Practical Feasibility

A comprehensive series of tests have been made on an experimental single-stage turbine to determine the cooling characteristics and the overall stage performance of a set of air-cooled turbine blades. These blades, which are described fully in Part I of this paper had, internally, a multiplicity of passages of small diameter along which cool air was passed through the whole length of the blade. Analysis of the, test data indicated that, when a quantity of cooling air amounting to 2 per cent, by weight, of the total gas-flow through the turbine is fed to the row of rotor blades, an increase in gas temperature of about 270 deg. C. (518 deg. F.) should be permissible above the maximum allowable value for a row of uncooled blades made from the same material. The degree of cooling achieved throughout each blade was far from uniform and large thermal stresses must result. It appears, however, that the consequences of this are not highly detrimental to the performance of the present type of blading, it being demonstrated that the main effect of the induced thermal stress is apparently to transfer the major tensile stresses to the cooler (and hence stronger) regions of the blade. The results obtained from the present investigations do not represent a limit to the potentialities of internal air-cooling, but form merely a first exploratory step. At the same time the practical feasibility of air cooling is made apparent, and advances up to the present are undoubtedly encouraging.

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Microwave Processing of Ceramics

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.857 ◽

2006 ◽

Vol 45 ◽

pp. 857-862 ◽

Cited By ~ 1

Author(s):

Isabel K. Lloyd ◽

Yuval Carmel ◽

Otto C. Wilson Jr. ◽

Geng Fu Xu

Keyword(s):

Thermal Conductivity ◽

Grain Size ◽

Heating Rate ◽

Thermal Gradients ◽

Heating Rates ◽

Volumetric Heating ◽

Wide Range ◽

Conventional Sintering ◽

Atmosphere Control ◽

Very High

Microwave (MW) processing is advantageous for processing ceramics with tailored microstructures. Its combination of volumetric heating, a wide range of controlled heating rates, atmosphere control and the ability to reach very high temperatures allows processing of 'difficult' materials like high thermal conductivity AlN and AlN composites and microstructure control in more readily sintered ceramics such as ZnO. MW sintering promotes development of thermal conductivity in AlN (225 W/mK) and its composites (up to 150W/mK inAlN-TiB2 and up to 129 W/mK in AlN-SiC when solid solution is avoided). In ZnO, heating rate controls sintered grain size. Increasing the heating rate from 5°C/min. to 4900°C decreases grain size from ~10 μm (comparable to conventional sintering of the same powder) to nearly the starting particle size (~ 1μm). Microstructural uniformity increases with sintering rate since ultra-rapid MW sintering minimizes the development of thermal gradients due to heat loss.

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Use of CFD to Improve Control Valve Effectiveness

Volume 3: Design and Analysis ◽

10.1115/pvp2019-93417 ◽

2019 ◽

Author(s):

Alton Reich

Keyword(s):

Flow Control ◽

Control Valve ◽

Steam Pressure ◽

Steam Flow ◽

Effective Control ◽

Flow Control Valve ◽

Flow Rates ◽

Wide Range ◽

Flow Through ◽

Inlet Conditions

Abstract Control valves are used to adjust fluid flow rates in an extremely wide variety of applications. This paper discusses a steam flow control valve that is required to operate with a fairly wide range of inlet conditions (steam pressure) and provide effective control over a fairly wide range of steam flow rates. In this particular case a valve design was developed using “classical” methods — a combination of experience and hand calculations. The valve was tested and it did not provide adequate control over the flow for the application. The valve redesign effort used CFD to gain insight into the flow through the valve in order to evaluate control performance before the valve was fabricated and assembled. Several internal geometries were assessed and compared in order to identify two configurations that would meet the flow control requirements. These configurations were fabricated and tested and deemed to be adequate.

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Adiabatic Effectiveness Measurements and Predictions of Leakage Flows Along a Blade Endwall

Journal of Turbomachinery ◽

10.1115/1.1929809 ◽

2005 ◽

Vol 127 (3) ◽

pp. 609-618 ◽

Cited By ~ 9

Author(s):

W. W. Ranson ◽

K. A. Thole ◽

F. J. Cunha

Keyword(s):

High Pressure ◽

Turbine Blades ◽

Leakage Flow ◽

Leakage Flows ◽

High Pressure Compressor ◽

Flow Through ◽

Cooling Air ◽

Low Speed Wind Tunnel ◽

Paper Address ◽

Good Agreement

Traditional cooling schemes have been developed to cool turbine blades using high-pressure compressor air that bypasses the combustor. This high-pressure forces cooling air into the hot main gas path through seal slots. While parasitic leakages can provide a cooling benefit, they also represent aerodynamic losses. The results from the combined experimental and computational studies reported in this paper address the cooling benefit from leakage flows that occur along the platform of a first stage turbine blade. A scaled-up, blade geometry with an upstream slot, a mid-passage slot, and a downstream slot was tested in a linear cascade placed in a low-speed wind tunnel. Results show that the leakage flow through the mid-passage gap provides only a small cooling benefit to the platform. There is little to no benefit to the blade platform that results by increasing the coolant flow through the mid-passage gap. Unlike the mid-passage gap, leakage flow from the upstream slot provides good cooling to the platform surface, particularly in certain regions of the platform. Relatively good agreement was observed between the computational and experimental results, although computations overpredicted the cooling.

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Influence of Turbulence Modelling to Condensing Steam Flow in the 3D Low-Pressure Steam Turbine Stage

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines ◽

10.1115/gt2016-57590 ◽

2016 ◽

Author(s):

Yogini Patel ◽

Giteshkumar Patel ◽

Teemu Turunen-Saaresti

Keyword(s):

Steam Turbine ◽

Stokes Equations ◽

Turbine Blades ◽

Rapid Change ◽

Low Pressure ◽

Turbulence Modelling ◽

Steam Flow ◽

Droplet Growth ◽

Steam Turbines ◽

Turbine Stage

With the tremendous role played by steam turbines in power generation cycle, it is essential to understand the flow field of condensing steam flow in a steam turbine to design an energy efficient turbine because condensation at low pressure (LP) turbine introduces extra losses, and erosion in turbine blades. The turbulence has a leading role in condensing phenomena which involve a rapid change of mass, momentum and heat transfer. The paper presents the influence of turbulence modelling on non-equilibrium condensing steam flows in a LP steam turbine stage adopting CFD code. The simulations were conducted using the Eulerian-Eulerian approach, based on Reynolds-averaged Navier-Stokes equations coupled with a two equation turbulence model, which is included with nucleation and droplet growth model for the liquid phase. The SST k-ω model was modified, and the modifications were implemented in the CFD code. First, the performance of the modified model is validated with nozzles and turbine cascade cases. The effect of turbulence modelling on the wet-steam properties and the loss mechanism for the 3D stator-rotor stage is discussed. The presented results show that an accurate computational prediction of condensing steam flow requires the turbulence to be modelled accurately.

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