Development and validation of a PIV processing routine for two-phase index-matched flows

2020 ◽  
Vol 23 (6) ◽  
pp. 951-970
Author(s):  
Andrew M. Bluestein ◽  
Douglas Bohl
Author(s):  
Avinash Singh

Abstract The stress-life (S-N) method along with the Palmgren-Miner cumulative damage theory is the simplest and the most commonly used fatigue life prediction technique. Its main advantage is that the material properties needed are easy to collect and life calculation is simple. However under many variable amplitude loading conditions, life predictions have been found to be unreliable. Various modifications have been proposed to the Palmgren-Miner theory, but they have not lead to more reliable life predictions. In this paper, a two-stage cumulative damage model will be developed and validated. This model divides fatigue life into two phases — a crack initiation phase and a crack propagation phase. It will be shown that the proposed method results in greatly improved life prediction capabilities. Also, the proposed method retains the simplicity of the S-N based approach in that the material data is still relatively simple to generate and the calculations are straightforward.


Author(s):  
Eric Hervieu ◽  
Emmanuel Jouet ◽  
Laurent Desbat

This paper describes the development and validation of a high spatial resolution X-ray tomograph devoted to investigate air-water two-phase flows. The device hardware is mainly composed of a 60 keV X-ray source, a detector and an accurate mechanical bench. This paper concentrates on accuracy quantification and emphasis is given on the reconstruction procedure. It is well known that absorption gradients induce reconstruction artifacts when using standard algorithms based on uniform regularization. In the particular case of two-phase flows in pipes, this leads to a poor measurement accuracy in the vicinity of the walls. To overcome such effects, improved algorithms have been developed in this study, involving different spatially adaptative regularization methods. A first calibration performed on static phantoms clearly exhibits the benefit brought by such advanced reconstruction algorithms. A validation procedure has been carried out on an air-water bubble column, equipped with an optical probe which can be translated in order to explore the 80 mm × 80 mm square cross section. Comparisons of local void fraction measurements have been performed pixel by pixel, and demonstrate the accuracy improvement induced by the advanced reconstruction algorithms.


Author(s):  
Matthew J. Blom ◽  
Michael J. Brear ◽  
Chris G. Manzie ◽  
Ashley P. Wiese

This paper is the first part of a two part study that develops, validates and integrates a one-dimensional, physics-based, dynamic boiler model suitable for application with model based control. Part 1 of this study extends and validates the existing, higher order modelling framework of Badmus et. al. [1] to boilers. This requires derivation of particular, one-dimensional forms of the equations for heat, mass and momentum transfer in single (liquid and gas) phase and two phase fluids with real fluid properties. The so-called ‘forcing term’ mapping functions in these equations only require knowledge of steady state system behaviour, and so can be obtained from steady state measurements throughout the boiler system. Additional models are also presented for other boiler components, including the steam drum in sub-critical boilers. The overall framework is then used to develop and validate a model of a GW scale, sub-critical boiler in an operating, electrical power plant. Overall, the model achieves reasonable agreement with the power plant dynamics during normal transient operations, including acceptable tracking of the drum dynamics and the steam at the boiler outlet. As such, this modelling framework appears suitable for developing models of sufficient fidelity yet retain an appropriate form for model reduction using singular perturbation analysis techniques, as demonstrated in Part 2 [2] of this study.


2002 ◽  
Vol 972 (1) ◽  
pp. 87-94 ◽  
Author(s):  
ERIC HERVIEU ◽  
EMMANUEL JOUET ◽  
LAURENT DESBAT

2021 ◽  
Vol 161 ◽  
pp. 108452
Author(s):  
Yutong Chen ◽  
Dalin Zhang ◽  
Yu Liang ◽  
Shibao Wang ◽  
Qifan Yu ◽  
...  

2018 ◽  
Author(s):  
Adrian Tentner ◽  
Prasad Vegendla ◽  
Dillon Shaver ◽  
Ananias Tomboulides ◽  
Aleks Obabko ◽  
...  

1996 ◽  
Vol 5 (4) ◽  
pp. 282-288 ◽  
Author(s):  
J Scribante ◽  
ME Muller ◽  
J Lipman

OBJECTIVE: To describe the research methodology used in development and validation of a scientific patient classification instrument for South African critical care patients. METHOD: This is a contextual, exploratory, and descriptive study. A two-phase validating model was used as a research method. In the development phase a literature review was carried out (domain identification), a provisional instrument developed (item generation), and a peer group discussion conducted (item formation). In the quantification phase 16 experts determined if both the items of the instrument and the entire instrument were content valid. The study was conducted within the framework of South African critical care nursing. RESULTS: In the peer group discussion the instrument was debated until consensus was reached. In the quantification phase, both the items of the instrument and the entire instrument were rated as content valid. CONCLUSIONS: Established patient classification systems can be successfully adapted and validated for local use.


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