scholarly journals Consistent Posttest Calculations for LOCA Scenarios in LOBI Integral Facility

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
F. Reventós ◽  
P. Pla ◽  
C. Matteoli ◽  
G. Nacci ◽  
M. Cherubini ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mass Flow ◽  
Scaling Factor ◽  
Test Facility ◽  
Data Bases ◽  
Integral Test ◽  
The Core ◽  
Active Elements ◽  
Accuracy Data

Integral test facilities (ITFs) are one of the main tools for the validation of best estimate thermalhydraulic system codes. The experimental data are also of great value when compared to the experiment-scaled conditions in a full NPP. The LOBI was a single plus a triple-loop (simulated by one loop) test facility electrically heated to simulate a 1300 MWe PWR. The scaling factor was 712 for the core power, volume, and mass flow. Primary and secondary sides contained all main active elements. Tests were performed for the characterization of phenomenologies relevant to large and small break LOCAs and special transients in PWRs. The paper presents the results of three posttest calculations of LOBI experiments. The selected experiments are BL-30, BL-44, and A1-84. They are LOCA scenarios of different break sizes and with different availability of safety injection components. The goal of the analysis is to improve the knowledge of the phenomena occurred in the facility in order to use it in further studies related to qualifying nodalizations of actual plants or to establish accuracy data bases for uncertainty methodologies. An example of procedure of implementing changes in a common nodalization valid for simulating tests occurred in a specific ITF is presented along with its confirmation based on posttests results.

Unsteady Flow and Aeroelasticity Behaviour of Aero-Engine Core Compressors During Rotating Stall and Surge

2006 ◽  
Author(s):  
M. Vahdati ◽  
G. Simpson ◽  
M. Imregun
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Mass Flow ◽  
Rotor Blade ◽  
Rotating Stall ◽  
Flow Reversal ◽  
The Core ◽  
Single Passage ◽  
Aero Engine ◽  
Operating Points

The paper will focus on two core-compressor instabilities, namely rotating stall and surge. Using a 3D viscous time-accurate flow representation, the front bladerows of a core-compressor were modelled in a whole-annulus fashion whereas the rest of bladerows were represented in single passage fashion. The rotating stall behaviour at two different compressor operating points was studied by considering two different variable-vane scheduling conditions for which experimental data were available. Using a model with 9 whole bladerows, the unsteady flow calculations were conducted on 32-CPUs of a parallel cluster, typical run times being around 3–4 weeks for a grid with about 60 million points. The simulations were conducted over several engine rotations. As observed on the actual development engine, there was no rotating stall for the first scheduling condition while mal-scheduling of the stator vanes created a 12 band rotating stall which excited the rotor blade 1st flap mode. In a separate set of calculations, the surge behaviour was modelled using a time-accurate single-passage representation of the core compressor. It was possible to predict not only flow reversal into the low pressure compression domain, but also the expected hysteresis pattern of the surge loop in terms of its mass flow vs pressure characteristic.

Simulating Analysis for Small Break LOCA Test Facilities by Applying the Volume Scaling With Reduced Pressure and Reduced Height

2001 ◽  
Author(s):  
S. K. Moussavian ◽  
M. A. Salehi
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Test Facility ◽  
Integral Test ◽  
Reduced Pressure ◽  
Simple Loop ◽  
Loss Of Coolant Accident ◽  
Reduced Height ◽  
Simulating Analysis ◽  
Loss Of Coolant

Abstract In this paper first we briefly define the different scaling schemes and scaling logic in which we use these schemes to simulate the Small-Break Loss Of Coolant Accident (SB-LOCA) in test facilities. The simple loop of the test facility is considered and the mass, momentum and energy conservation equations are used for the derivation of the scaling model. The variations of mass flow rate, pressure drop and the void fraction in the loop as functions of the time scale or the inventories are obtained. Finally, the calculated results from the simulating schemes are compared with the experimental data previously obtained in an integral test facility.

System-Core Thermal Hydraulic Interaction During a Reflood Phase of a Cold-Leg LBLOCA in the Atlas Integral Effect Test Facility

2009 ◽  
Author(s):  
Seok Cho ◽  
Hyun-Sik Park ◽  
Ki-Yong Choi ◽  
Kyong-Ho Kang ◽  
Yeon-Sik Kim ◽  
...  
Keyword(s):  
Experimental Data ◽  
Boundary Condition ◽  
Water Flow Rate ◽  
Experimental Tests ◽  
Test Facility ◽  
Hydraulic Behavior ◽  
The Core ◽  
Analysis Methodology ◽  
Integral Effect ◽  
Effect Test

A series of experimental tests to simulate a reflood phase of a cold-leg LBLOCA of the APR1400 have been performed by using the ATLAS facility. This paper describes related experimental results with respect to the thermal-hydraulic behavior in the core and the system-core interactions during the reflood phase of cold-leg LBLOCA condition. The present descriptions will be focus on the LB-CL-09, LB-CL-11, LB-CL-14, and LB-CL-15 tests performed by using the ATLAS. The LB-CL-09 is the integral effect test with conservative boundary condition, and LB-CL-11, and -14 are the integral effect tests with realistic boundary condition, and the LB-CL-15 is the separated effect test. The objectives of these tests are to investigate the thermal-hydraulic behavior during an entire reflood phase, and to provide reliable experimental data for validating the LBLOCA analysis methodology for the APR1400. The initial and boundary conditions were obtained by applying scaling ratios to the MARS simulation results for the LBLOCA scenario of the APR1400. The ECC water flow rate from the safety injection tanks and the decay heat were simulated from the start of the reflood phase. The present experimental data showed that the cladding temperature behavior is closely related to the collapsed water level in the core and the downcomer.

Unsteady Flow and Aeroelasticity Behavior of Aeroengine Core Compressors During Rotating Stall and Surge

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
M. Vahdati ◽  
G. Simpson ◽  
M. Imregun
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Mass Flow ◽  
Rotor Blade ◽  
Low Pressure ◽  
Rotating Stall ◽  
Flow Reversal ◽  
The Core ◽  
Single Passage ◽  
Operating Points

This paper will focus on two core-compressor instabilities, namely, rotating stall and surge. Using a 3D viscous time-accurate flow representation, the front bladerows of a core compressor were modeled in a whole-annulus fashion whereas the rest of bladerows were represented in single-passage fashion. The rotating stall behavior at two different compressor operating points was studied by considering two different variable-vane scheduling conditions for which experimental data were available. Using a model with nine whole bladerows, the unsteady flow calculations were conducted on 32 CPUs of a parallel cluster, typical run times being around 3–4 weeks for a grid with about 60×106 points. The simulations were conducted over several engine rotations. As observed on the actual development engine, there was no rotating stall for the first scheduling condition while malscheduling of the stator vanes created a 12-band rotating stall which excited the rotor blade first flap mode. In a separate set of calculations, the surge behavior was modeled using a time-accurate single-passage representation of the core compressor. It was possible to predict not only flow reversal into the low pressure compression domain but also the expected hysteresis pattern of the surge loop in terms of its mass flow versus pressure characteristic.

Analysis of VVER-1000 Large and Small Break LOCA Experiments With RELAP5/MOD3.2

2004 ◽  
Author(s):  
Maxym Rychkov ◽  
Utkarsh Chikkanagoudar ◽  
Bal Raj Sehgal
Keyword(s):  
Experimental Data ◽  
Test Data ◽  
Large Scale ◽  
Nuclear Safety ◽  
Test Facility ◽  
Integral Test ◽  
Power Scale ◽  
Accident Scenarios

A RELAP5 model for the analysis of the PSB-VVER test facility was developed by the EREC in Russia. The PSB-VVER is a large-scale integral test facility to model the VVER-1000 type NPP. The volume and power scale in this test facility is 1:300 and the elevation scale is 1:1, which corresponds to the elevation mark of the reactor prototype. At the Division of Nuclear Safety, RIT, Sweden, we have modified the PSB-VVER facility’s RELAP5 model in order to analyze two of the transient tests performed on the PSB-VVER facility, which serve as the validation matrix described by NEA/CSNI. The objective of the work conducted was to validate the results obtained from RELAP5’s calculation with the supplied experimental data from the PSB-VVER test facility. Two accident scenarios have been calculated and analyzed. After being verified against the “11% UP LOCA” test data, the RELAP5/MOD3.2 model was used for a so-called “blind” transient calculation of the test “2×25% HL LOCA” and the results obtained were compared with the experimental data provided after the calculation.

Two-Phase Flow Measurement Studies for the SPES3 Integral Test Facility for IRIS Reactor Simulation

2010 ◽  
Author(s):  
Matteo Greco ◽  
Roberta Ferri ◽  
Andrea Achilli ◽  
Stefano Gandolfi ◽  
Cinzia Congiu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Mass Flow Rate ◽  
Void Fraction ◽  
Mass Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Test Facility ◽  
Phase Flow ◽  
Two Phase ◽  
Integral Test

The measurement of two-phase flow parameters has never been an easy task in the experimental thermal-hydraulics and the need of such measurements in the SPES3 facility has led to investigation of different possibilities and evaluation methods to determine mass flows and energies. This paper deals with the theoretical prediction of the two-phase mass flow rate by the development of a mathematical model for a spool piece, consisting of a drag disk, a turbine and a void fraction detector. Data obtained by simulation of DBAs in the SPES3 facility, with the RELAP5 thermal-hydraulic code, have provided the reference conditions for defining the main thermal-hydraulic parameter ranges and selecting a set of instruments potentially suitable to measure and derive the required quantities. The governing equation and the instrumentation output are defined for each device. Three different turbine models (Aya, Rouhani and volumetric) have been studied to understand which one better adapts to two-phase flow conditions and to investigate the best instrument combination. The mathematical model has been tested versus the RELAP5 results with a reverse process where calculated variables, like void fraction, quality and slip ratio, are given as input to a specifically developed program to get back the mass flow rate. The analytical results, verified versus the DVI break transient, well agree with the RELAP5 mass flow rate. Specific tests on proper experimental loops are required to verify the analytical studies.

Scaling analysis of core pressure drop in reduced height integral test facility

Kerntechnik ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. 178-180
Author(s):  
P. Ju ◽  
B. Long ◽  
L. Li ◽  
Q. Su ◽  
X. Wu ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Test Facility ◽  
Scaling Analysis ◽  
Integral Test ◽  
Reduced Height

Performance prediction of transonic axial multistage compressor based on one-dimensional meanline method

2021 ◽  
pp. 095765092199881
Author(s):  
Yingying Zhang ◽  
Shijie Zhang
Keyword(s):  
Experimental Data ◽  
Mass Flow ◽  
Flow Separation ◽  
Performance Prediction ◽  
Factor Model ◽  
Separation Method ◽  
Prediction Program ◽  
Blockage Factor ◽  
Reliability And Robustness ◽  
Work Done

This study proposes a 1D meanline program for the modeling of modern transonic axial multistage compressors. In this method, an improved blockage factor model is proposed. Work-done factor that varies with the compressor performance conditions is added in this program, and at the same time a notional blockage factor is kept. The coefficient of deviation angle model is tuned according to experimental data. In addition, two surge methods that originated from different sources are chosen to add in and compare with the new method called mass flow separation method. The salient issues presented here deal first with the construction of the compressor program. Three well-documented National Aerodynamics and Space Administration (NASA) axial transonic compressors are calculated, and the speedlines and aerodynamic parameters are compared with the experimental data to verify the reliability and robustness of the proposed method. Results show that consistent agreement can be obtained with such a performance prediction program. It was also apparent that the two common methods of surge prediction, which rely upon either stage or overall characteristic gradients, gave less agreement than the method called mass flow separation method.

scholarly journals Isolation and Molecular Characterization of the Romaine Lettuce Phylloplane Mycobiome

2021 ◽  
Vol 7 (4) ◽  
pp. 277
Author(s):  
Danny Haelewaters ◽  
Hector Urbina ◽  
Samuel Brown ◽  
Shannon Newerth-Henson ◽  
M. Catherine Aime
Keyword(s):  
Lactuca Sativa ◽  
New Combinations ◽  
Food Spoilage ◽  
Human Pathogens ◽  
Plant Leaves ◽  
Romaine Lettuce ◽  
Future Studies ◽  
The Core ◽  
American Agriculture

Romaine lettuce (Lactuca sativa) is an important staple of American agriculture. Unlike many vegetables, romaine lettuce is typically consumed raw. Phylloplane microbes occur naturally on plant leaves; consumption of uncooked leaves includes consumption of phylloplane microbes. Despite this fact, the microbes that naturally occur on produce such as romaine lettuce are for the most part uncharacterized. In this study, we conducted culture-based studies of the fungal romaine lettuce phylloplane community from organic and conventionally grown samples. In addition to an enumeration of all such microbes, we define and provide a discussion of the genera that form the “core” romaine lettuce mycobiome, which represent 85.5% of all obtained isolates: Alternaria, Aureobasidium, Cladosporium, Filobasidium, Naganishia, Papiliotrema, Rhodotorula, Sampaiozyma, Sporobolomyces, Symmetrospora and Vishniacozyma. We highlight the need for additional mycological expertise in that 23% of species in these core genera appear to be new to science and resolve some taxonomic issues we encountered during our work with new combinations for Aureobasidiumbupleuri and Curvibasidium nothofagi. Finally, our work lays the ground for future studies that seek to understand the effect these communities may have on preventing or facilitating establishment of exogenous microbes, such as food spoilage microbes and plant or human pathogens.

scholarly journals Mass Flow, Pressure Drop, and Leakage Dependent Modeling and Characterization of Solar Air Collectors

2014 ◽  
Vol 48 ◽  
pp. 250-263 ◽  
Author(s):  
Christian Welz ◽  
Christoph Maurer ◽  
Paolo Di Lauro ◽  
Gerhard Stryi-Hipp ◽  
Michael Hermann
Keyword(s):  
Pressure Drop ◽  
Mass Flow ◽  
Flow Pressure
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