The Numerical and Experimental Study of a Power Plant Condenser

1993 ◽  
Vol 115 (2) ◽  
pp. 435-445 ◽  
Author(s):  
C. Zhang ◽  
A. C. M. Sousa ◽  
J. E. S. Venart
Keyword(s):  
Experimental Study ◽  
Power Plant ◽  
Tube Bundle ◽  
Control Volume ◽  
Water Pressure ◽  
Three Dimensional ◽  
Tube Sheet ◽  
Data Set ◽  
Numerical Predictions ◽  
Inlet Tube

A numerical and experimental study to evaluate the performance of a power plant condenser has been carried out. Numerically, physically relevant effects are taken into consideration through a quasi-three-dimensional approach. The equations governing the conservation of mass, momentum, and air mass fraction are solved in primitive variable form using a semi-implicit consistent control-volume formulation in which a segregated pressure correction linked algorithm is employed. The modeling of the condenser geometry, including tube bundle and baffle plates, is carried out based on a porous medium concept using applicable flow, heat, and mass transfer resistances. The measurement program included determinations of the steam pressures on the tube bundle perimeter (96 points), steam temperatures (96 locations), inlet tube sheet water pressure distributions (26 measurements), outlet tube sheet flows and temperatures (26 points), hot well flow, and enthalpy in addition to all makeup and extraction flow rates as a function of load. The measurement program and its implementation are briefly described. One data set is compared with the numerical predictions.

Numerical Modeling Using a Quasi-Three-Dimensional Procedure for Large Power Plant Condensers

1994 ◽  
Vol 116 (1) ◽  
pp. 180-188 ◽  
Author(s):  
C. Zhang
Keyword(s):  
Power Plant ◽  
Mass Fraction ◽  
Tube Bundle ◽  
Control Volume ◽  
Three Dimensional ◽  
Predictive Capability ◽  
Large Power ◽  
Operational Conditions ◽  
Proposed Model ◽  
Flow Heat

A quasi-three-dimensional numerical model is proposed to predict the performance of large power plant condensers. The proposed model is applied to a 350 MW power plant condenser under two different loading and operational conditions to demonstrate its predictive capability. The predictions are compared with the experimental data. The comparison is favorable. The equations governing the conservation of mass, momentum, and air mass fraction are solved in primitive variable form using a semi-implicit consistent control-volume formulation in which a segregated pressure correction linked algorithm is employed. The modeling of the condenser geometry, including the tube bundle and baffle plates, is carried out based on a porous media concept using applicable flow, heat, and mass transfer resistances.

Experimental and Numerical Investigation of Fluid Dynamics of the Bounded and Unbounded Triangular Jets

2008 ◽  
Author(s):  
Reza Riahi ◽  
Farshid Bagheri ◽  
Bijan Farhanieh
Keyword(s):  
Experimental Study ◽  
Bounded Domain ◽  
Control Volume ◽  
Three Dimensional ◽  
Unbounded Domains ◽  
Numerical Code ◽  
Strong Mixing ◽  
Free Boundaries ◽  
Collocated Grid ◽  
Turbulent Jet Flow

In the present study, the fluid characteristics of triangular turbulent jet flow are considered experimentally and numerically. The results of spatially developed three-dimensional jet, issued from an equilateral triangular nozzle are presented. The jet is discharged to both bounded and unbounded domains. Because of the wind tunnel set up restrictions, the experimental study has done just for the bounded domain. The hot-wire anemometry is used for experimental study. A numerical method employing control volume approach with collocated grid arrangement which couples the velocity and pressure fields with SIMPLEC algorithm is introduced to discrete the governing equations of fluid flow. The turbulent stresses are approximated using k-ε model. Both bounded and unbounded domains have been studied using a numerical code. The velocity field is presented using profiles and contours. Comparison of numerical and experimental results for the bounded domain shows a good agreement. The flow pattern results show that the strong mixing and flow entrainment from free boundaries into the jet takes place and eventuates to expand the jet highly at the unbounded domain.

A Calibration of a Feedwater Flowmeter Installed to Model Loop of a Nuclear Power Plant Using High Reynolds Number Facility

2008 ◽  
Author(s):  
Noriyuki Furuichi ◽  
Yoshiya Terao ◽  
Masaki Takamoto
Keyword(s):  
Reynolds Number ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
High Reynolds Number ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Calibration Result ◽  
Calibration Facility ◽  
High Reynolds

A calibration result of ultrasonic flowmeters using in a feedwater flowrate in a nuclear power plant, is described under a variety of upstream conditions using the new high Reynolds number calibration facility. The pipe layouts are classified to five type three-dimensional one with two or three elbows. The flow conditioners are tube bundle type and Mitsubishi type. Pipe Reynolds number is up to 1.6×107. The large effect of the flow conditioner and pipe layout is observed for cramp-on type. For multi-path type, individuality is observed.

Three-Dimensional Study of Unsteady Flow in Fractured Horizontal Wells

2009 ◽  
Vol 283-286 ◽  
pp. 256-261
Author(s):  
N. Mimouni ◽  
Salahs Chikh
Keyword(s):  
Control Volume ◽  
Three Dimensional ◽  
Geometrical Parameters ◽  
Optimum Number ◽  
Numerical Predictions ◽  
Fractured Horizontal Well ◽  
Hybrid Grid ◽  
Diffusivity Equation ◽  
Induced Fractures ◽  
Fractured Horizontal Wells

Numerical predictions are carried out in order to investigate the fractured horizontal well behaviour. A control volume based approach is used to solve the transient 3D diffusivity equation adopting an irregular hybrid grid. Effect of several parameters such as reservoir characteristics, fracture properties and physical and geometrical parameters of the reservoir and the well that may affect the well productivity and production are discussed. Simulation results allow to predict the optimum number of induced fractures.

Comparison Between Numerical and Experimental Gas Side Heat Transfer and Pressure Drop of a Tube Bank With Solid and Segmented Circular I-Fins

2012 ◽  
Author(s):  
Rene Hofmann ◽  
Heimo Walter
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Finned Tube ◽  
Three Dimensional Model ◽  
Finned Tubes ◽  
Numerical Predictions ◽  
Staggered Arrangement ◽  
Flow Experiments

In the present work, a comparison between numerical and experimental gas side heat transfer and pressure drop for a tube bundle with solid and segmented circular finned tubes in a staggered arrangement is investigated. For the numerical simulations a three dimensional model of the finned tube are applied. Renormalization group theory (RNG) based k–ε turbulence model was used to calculate the turbulent flow. Experiments have been carried out to validate the numerical predictions. The numerical results for the Nu-number and pressure drop coefficient show a good agreement with the data from measurement. A comparison between solid and segmented finned tubes from the global calculation of the Nu-numbers within the analyzed Re-range shows an enhancement by applying segmented finned tubes rather than finned tubes with solid fins.

Three-dimensional image analysis and visualization in confocal light microscopy

1993 ◽  
Vol 51 ◽  
pp. 158-159
Author(s):  
J. K. Samarabandu ◽  
R. Acharya ◽  
D. R. Pareddy ◽  
P. C. Cheng
Keyword(s):  
Depth Perception ◽  
Computer Graphic ◽  
Three Dimensional ◽  
Cellular Organization ◽  
Data Set ◽  
Computational Burden ◽  
Interactive Operation ◽  
Cell Organization ◽  
Confocal Images ◽  
3D Digitization

In the study of cell organization in a maize meristem, direct viewing of confocal optical sections in 3D (by means of 3D projection of the volumetric data set, Figure 1) becomes very difficult and confusing because of the large number of nucleus involved. Numerical description of the cellular organization (e.g. position, size and orientation of each structure) and computer graphic presentation are some of the solutions to effectively study the structure of such a complex system. An attempt at data-reduction by means of manually contouring cell nucleus in 3D was reported (Summers et al., 1990). Apart from being labour intensive, this 3D digitization technique suffers from the inaccuracies of manual 3D tracing related to the depth perception of the operator. However, it does demonstrate that reducing stack of confocal images to a 3D graphic representation helps to visualize and analyze complex tissues (Figure 2). This procedure also significantly reduce computational burden in an interactive operation.

EMCAT: An automatic image-processing system for electron-microscopic tomography

1994 ◽  
Vol 52 ◽  
pp. 418-419
Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Image Processing ◽  
Structural Information ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Processing System ◽  
Electron Microscopic ◽  
Data Set ◽  
Ordered Structures ◽  
Automatic Image Processing ◽  
Em Tomography

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.

THREE-DIMENSIONAL PLANNING OF BRACHYTHERAPY FOR LOCALLY ADVANCED CERVICAL CANCER BY CT/MRI IMAGES

2018 ◽  
Vol 64 (5) ◽  
pp. 645-650
Author(s):  
Olga Kravets ◽  
Yelena Romanova ◽  
Oleg Kozlov ◽  
Mikhail Nechushkin ◽  
A. Gavrilova ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Local Control ◽  
Control Volume ◽  
Locally Advanced ◽  
Three Dimensional ◽  
Advanced Cervical Cancer ◽  
3D Ct ◽  
Mri Imaging ◽  
Tumor Target ◽  
Locally Advanced Cervical Cancer

We present our results of 3D CT/MRI brachytherapy (BT) planning in 115 patients with locally advanced cervical cancer T2b-3bN0-1M0. The aim of this study was to assess the differences in the visualization of tumor target volumes and risk organs during the 3D CT/MRI BT. The results of the study revealed that the use of MRI imaging for dosimetric planning of dose distribution for a given volume of a cervical tumor target was the best method of visualization of the soft tissue component of the tumor process in comparison with CT images, it allowed to differentially visualize the cervix and uterine body, directly the tumor volume. Mean D90 HR-CTV for MRI was 32.9 cm3 versus 45.9 cm3 for CT at the time of first BT, p = 0.0002, which is important for local control of the tumor process. The contouring of the organs of risk (bladder and rectum) through MRI images allows for more clearly visualizing the contours, which statistically significantly reduces the dose load for individual dosimetric planning in the D2cc control volume, і.є. the minimum dose of 2 cm3 of the organ of risk: D2cc for the bladder was 24.3 Gy for MRI versus 34.8 Gy on CT (p = 0.045); D2cc for the rectum - 18.7 Gy for MRI versus 26.8 Gy for CT (p = 0.046). This is a prognostically important stage in promising local control, which allows preventing manifestation of radiation damage.

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