scholarly journals RESEARCH OF FLUID FLOW IN TWO-DIMENSIONAL AND THREE-DIMENSIONAL FORMULATION IN THE FLOW PART OF A HIGH-PRESSURE FRANCIS TURBINE

2019 ◽  
Vol 0 (1) ◽  
pp. 72-76
Author(s):  
Konstantin Mironov ◽  
Yuliia Oleksenko
Keyword(s):  
High Pressure ◽  
Fluid Flow ◽  
Three Dimensional ◽  
Francis Turbine ◽  
Two Dimensional ◽  
Flow Part

Numerical Simulations of Heat Transfer and Fluid Flow for a Rotating High-Pressure Turbine

2006 ◽  
Author(s):  
F. Mumic ◽  
L. Ljungkruna ◽  
B. Sunden
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Fluid Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbulence Models ◽  
High Pressure Turbine ◽  
Experimental Heat ◽  
Commercial Code ◽  
Stator Vane

In this work, a numerical study has been performed to simulate the heat transfer and fluid flow in a transonic high-pressure turbine stator vane passage. Four turbulence models (the Spalart-Allmaras model, the low-Reynolds-number realizable k-ε model, the shear-stress transport (SST) k-ω model and the v2-f model) are used in order to assess the capability of the models to predict the heat transfer and pressure distributions. The simulations are performed using the FLUENT commercial software package, but also two other codes, the in-house code VolSol and the commercial code CFX are used for comparison with FLUENT results. The results of the three-dimensional simulations are compared with experimental heat transfer and aerodynamic results available for the so-called MT1 turbine stage. It is observed that the predictions of the vane pressure field agree well with experimental data, and that the pressure distribution along the profile is not strongly affected by choice of turbulence model. It is also shown that the v2-f model yields the best agreement with the measurements. None of the tested models are able to predict transition correctly.

Multiscale reservoir surveillance and monitoring

2021 ◽  
Vol 40 (5) ◽  
pp. 383-384
Author(s):  
Mohammed Badri ◽  
Ali Yousif ◽  
Maged Mabrook
Keyword(s):  
Fluid Flow ◽  
Seismic Data ◽  
Three Dimensional ◽  
Oil Reservoirs ◽  
Two Dimensional ◽  
Sweep Efficiency ◽  
Fluid Movement ◽  
Integrate Data ◽  
Fluid Imaging

Geoscientists and reservoir engineers are challenged to integrate data of different scales to better understand fluid movement in oil reservoirs. Different technologies are capable of imaging fluid movement in the reservoir at different scales. Two-dimensional fluid imaging has been achieved recently through crosswell and surface-to-borehole electromagnetic (EM) measurements. Three-dimensional fluid movement imaging has shown potential by using surface seismic data volumes. The Multiscale Reservoir Surveillance and Monitoring Workshop, held virtually 7–9 December 2020, attempted to address the challenge of how to integrate these measurements obtained at different scales into a workflow to improve the understanding of fluid flow, which is critical for sweep efficiency and recovery.

3D Geometric Modeling of Francis Turbine Blades Based on Wooden Patterns and UG Software

2014 ◽  
Vol 596 ◽  
pp. 606-609
Author(s):  
Lei Lu ◽  
Li Da Zhang
Keyword(s):  
Geometric Modeling ◽  
Simulation Analysis ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Reference Value ◽  
Francis Turbine ◽  
Two Dimensional ◽  
Three Dimensional Modeling ◽  
Blade Section ◽  
Spatial Coordinates

To quickly and easily get a smooth and accurate 3D model of blades, This paper was based on the two-dimensional wooden patterns of the existing francis turbine blades in "AutoCAD", by importing UG software platform, directly translating two-dimensional lines to get three-dimensional wooden patterns, without calculating the spatial coordinates of distribution points on the blade section lines, obtaining the optimized smooth pressure sides and suction sides of the blades by characteristic surface intersecting lines, after partial rounding and sewing the sheets, the process of three-dimensional modeling of blades was finally completed. This takes a solid foundation for hydraulic performance prediction and CFD numerical simulation analysis of the francis turbine. The blade modeling method described in this article has some reference value.

INCOMPRESSIBLE FLUIDS

2005 ◽  
Vol 20 (27) ◽  
pp. 6122-6132 ◽  
Author(s):  
S. G. RAJEEV
Keyword(s):  
Fluid Flow ◽  
Incompressible Fluid ◽  
Quantum Groups ◽  
Three Dimensional ◽  
Incompressible Fluids ◽  
Two Dimensional ◽  
Incompressible Fluid Flow ◽  
Fluid System ◽  
Random Forces ◽  
Turbulent Incompressible Fluid

We propose a model for random forces in a turbulent incompressible fluid by balancing the energy gain from fluctuations against dissipation by viscosity. This leads to a more singular covariance distribution for the random forces than is ordinarily allowed. We then propose regularization of the fluid system by matrix models. A formula for entropy of a two dimensional fluid is derived and then a vorticity profile of a hurricane that maximizes entropy. A regularization of three dimensional incompressible fluid flow using quantum groups is also proposed.

CFD High L/D Riser Modeling Study

2007 ◽  
Author(s):  
Yiannis Constantinides ◽  
Owen H. Oakley ◽  
Samuel Holmes
Keyword(s):  
Fluid Flow ◽  
Computer Technology ◽  
Deep Water ◽  
Structural Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Flow Simulations ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Good Agreement

Fully three dimensional fluid flow simulations are used with a simple structural model to simulate very long risers. This method overcomes many shortcomings of methodologies based on two dimensional flow simulations and can correctly include the effects of three dimensional structures such as strakes, buoyancy modules and catenary riser shapes. The method is benchmarked against laboratory and offshore experiments with model risers of length to diameter ratios up to 4,000. RMS values of vortex induced vibration motions are shown to be in good agreement with measurements. The resources needed to model ultra deep water drilling and production risers are estimated based on current computer technology.

The mixing layer: deterministic models of a turbulent flow. Part 2. The origin of the three-dimensional motion

1984 ◽  
Vol 139 ◽  
pp. 67-95 ◽  
Author(s):  
G. M. Corcos ◽  
S. J. Lin
Keyword(s):  
Mixing Layer ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Streamwise Vorticity ◽  
Deterministic Models ◽  
Three Dimensional Flow ◽  
Turbulent Mixing Layer ◽  
Flow Part ◽  
Difference Calculation ◽  
Mechanism Of Growth

Experimental evidence suggests that in the turbulent mixing layer the fundamental mechanism of growth is two-dimensional and little affected by the presence of vigorous three-dimensional motion. To quantify this apparent property and study the growth of streamwise vorticity, we write for the velocity field \[ {\boldmath V}(x, t) = {\boldmath U}(x, z, t) + {\boldmath u}(x, y, z, t), \] where U is two-dimensional and u is three-dimensional. In a first version of the problem U is independent of u, while in the second U is the spanwise average of V. In both cases the equation for u is linearized around U. The equations for U and u are solved simultaneously by a finite-difference calculation starting with a slightly disturbed parallel shear layer.The solutions provide a detailed description of the growth of the three-dimensional motion. They show that its characteristics are dictated by the distribution of spanwise vorticity which results from roll-up and pairing. Pairing inhibits its growth. The solutions also demonstrate that even when the three-dimensional flow attains large amplitudes it has a negligible effect on the interaction of spanwise vortices and thus on the growth of the layer.

Electro Thermal Modeling of the Micro Flow Sensor With Feedback Control Circuit Using SPICE

2007 ◽  
Author(s):  
Shoji Kamiunten ◽  
Hidetomo Nagayo ◽  
Masahiro Motosuke ◽  
Shinji Honami
Keyword(s):  
Fluid Flow ◽  
Integrated Circuit ◽  
Thermal Modeling ◽  
Three Dimensional ◽  
Electric Circuit ◽  
General Purpose ◽  
Flow Sensor ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Micro Flow

This paper reports an efficient electro-thermal modeling technique for the Micro Flow Sensor (MFS) having an ensured thermal insulation structure with a thin silicon nitride membrane. Both the thermal fluid flow around two-heater MFS and the electric circuit were modeled together using a commercial general-purpose circuit simulator based on SPICE (Simulation Program with Integrated Circuit Emphasis). Two-dimensional laminar Poiseuille channel flow was assumed as the flow field in the model. Remarkable features of this technique are as follows: a partial three-dimensional lumped thermal network model involved in a two dimensional one, single segment for spanwise direction, and the forced convective heat transfer calculated by energy balance at each node in the fluid flow. The simulation and measurement results on the sensor characteristics were in good agreement.

Visualization Study on Droplet-Entrainment in a High-Speed Gas Jet Into a Liquid Pool

2018 ◽  
Author(s):  
Taro Sugimoto ◽  
Shimpei Saito ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
Akihiro Uchibori ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Film ◽  
Flow Structure ◽  
Test Section ◽  
High Speed ◽  
Tube Wall ◽  
Three Dimensional ◽  
Gas Jet ◽  
Two Dimensional ◽  
Pressure Steam

A sodium-cooled fast reactor (SFR) is now under development in Japan. A shell-and-tube type once-through heat exchanger is to be installed to generate steam in the design. Low-pressure hot sodium flows in the shell side and high-pressure water, which heated to become steam, flows in the tube side. It has been anticipated that a pin hole is formed on the tube wall and high-pressure steam blows out from the hole. When a high-pressure steam flows out from the tube hole, a high-speed steam jet is formed in the sodium coolant. Fine sodium droplets are torn off from the sodium surface and entrained into the steam jet. Sodium-water chemical reaction causes an increase of entrained droplet temperature. The hot and high-speed sodium entrained droplets attack the wall of a neighboring tube and cause a wastage on the tube wall, which may lead to a failure propagation. In Japan Atomic Energy Agency (JAEA), an analysis code for the sodium-water reaction phenomenon, called SERAPHIM, has already been developed. Visualization data is required to validate the liquid entrainment model in this code. Since the flow velocity at the gas leakage is a sonic speed, it is extremely difficult to visualize the inside of the gas jet. Experiments have been carried out to visualize this phenomenon in the past; however, experimental data for model validation has not been entirely obtained due to the above-mentioned difficulty. Thus, the motivation of this study is to examine the possibility of visualization method and to clarify flow structure. To this end, we first performed the preliminary experiments using simple test facilities. Two types of test sections were used in the experiments: three-dimensional one and two-dimensional one. In the experiment using the three-dimensional one, we tried to visualize a more realistic phenomenon. Through this experiment, the whole gas-jet behavior was clearly captured. However, we found that the detailed droplet-entrainment behavior in a gas jet could not be obtained in this setup, especially at high-velocity conditions. Then, we carried out the experiments using the two-dimensional one. In these experiments, the flow structure of a gas jet was simplified. However, it was difficult to distinguish the liquid film formed on the wall surface of the test section from the entrained droplets. We considered that the liquid film is formed due to the nozzle outlet shape and improved the test section. By experiments with new test section, we succeeded in visualizing entrained droplets of relatively large diameter and calculated droplet diameter distribution. Then, we discussed the mechanism of entrained droplet behavior.

Three-Dimensional Steady-State String Motion in a Fluid Flow

2004 ◽  
Vol 71 (6) ◽  
pp. 894-895
Author(s):  
Roman Miroshnik
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Three Dimensional ◽  
Initial Approximation ◽  
Invariant Curve ◽  
Perturbation Scheme ◽  
Two Dimensional ◽  
Flowing Medium ◽  
Steady State Motion ◽  
Existence Conditions

The phenomenon of three-dimensional (3D) steady-state motion of a string traveling along an invariant curve in a flowing medium is studied. Existence conditions are found using a perturbation scheme where a known two-dimensional (2D) solution is used as an initial approximation.

Superhard three-dimensional B3N4 with two-dimensional metallicity

2017 ◽  
Vol 5 (24) ◽  
pp. 5897-5901 ◽  
Author(s):  
Chenlong Xie ◽  
Mengdong Ma ◽  
Chao Liu ◽  
Yilong Pan ◽  
Mei Xiong ◽  
...  
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Ambient Pressure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Metallic Conduction ◽  
Boron Sheets

Using first-principles calculations, we uncovered that t-B3N4 is metastable at ambient pressure, but becomes stable under high pressure. The metallic conduction of t-B3N4 is interrupted by the insulated boron sheets stacked along the c axis, giving rise to its 2D metallicity.

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