scholarly journals Distribution of chlorine sanitizer in a flume tank: Numerical predictions and experimental validation

LWT ◽  
2022 ◽  
Vol 155 ◽  
pp. 112888
Author(s):  
Juzhong Tan ◽  
Jiyoon Yi ◽  
Xu Yang ◽  
Hyosik Lee ◽  
Nitin Nitin ◽  
...  
Author(s):  
Tomoaki Utsunomiya ◽  
Eiichi Watanabe ◽  
Tetsuya Hiraishi ◽  
Takatoshi Noguchi ◽  
Syuji Yamamoto

This paper presents a hydroelastic analysis of pontoon-, semisubmersible-, and hybrid-type VLFS and its experimental validation. In the analysis, the detailed configuration of the experimental model is considered by using three dimensional finite element (FE) method. Experimental models measuring 15m in length, 3m in width and 0.03–0.23m in draft (depending on whether it is the pontoon and semisubmersible part) are built. The experiment has been made in the wave-basin with the bottom-slope of 1/75. At the same time, a hydroelastic analysis is carried out using the same models as the experimental ones in a wave-basin with flat as well as slanting bottom with slope of 1/75. By comparing the numerical results and experiment, the effect of bottom slope is verified. In the analysis of the semisubmersible part, the effect of viscous damping is considered by using the drag force formula with assumed drag force coefficient of 2.0. A comparison between the experiment and the analytical results indicates that numerical results from the semisubmersible part with additional effects of viscous damping agree better with the experimental results than those without. An experiment using irregular waves is also carried out and compared with the numerical predictions. Finally, the steady drift forces are analyzed using the far-field method and compared with the experiment.


2009 ◽  
Vol 76 (2) ◽  
Author(s):  
Marcela A. Cruchaga ◽  
Diego J. Celentano ◽  
Tayfun E. Tezduyar

We present the numerical and experimental analyses of the collapse of a water column over an obstacle. The physical model consists of a water column initially confined by a closed gate inside a glass box. An obstacle is placed between the gate and the right wall of the box, inside the initially unfilled zone. Once the gate is opened, the liquid spreads in the container and over the obstacle. Measurements of the liquid height along the walls and a middle control section are obtained from videos. The computational modeling is carried out using a moving interface technique, namely, the edge-tracked interface locator technique, to calculate the evolution of the water-air interface. The analysis involves a water-column aspect ratio of 2, with different obstacle geometries. The numerical predictions agree reasonably well with the experimental trends.


Author(s):  
Navin Kumar ◽  
Debjyoti Banerjee

“T-history method” is widely used for characterization of thermal properties of Phase Change Material (PCM). In this study improvements are proposed to the experimental protocol used in the conventional T-History method. Experimental validation of numerical predictions for various samples of PCM were performed using the proposed measurement technique. This enabled the evaluation of the improvements in the proposed approach as well as for analyzing the experimental results. This involved measurement of temperature at the surface and in the center of the PCM samples (as well as that of the reference sample materials). The proposed modifications enable enhanced accuracy for estimation of the material properties (when compared to the conventional approaches). The estimates from the proposed approach were observed to be within 10% of the measured values obtained using Differential Scanning Calorimetry (DSC). The proposed approach is amenable to testing large sample sizes, is simpler to implement, provides more rapid data collection and is more cost-effective than that obtained using standard DSC protocols.


2018 ◽  
Author(s):  
Svjetlana Stekovic ◽  
Erin J. Nissen ◽  
Mithun Bhowmick ◽  
D. Scott Stewart ◽  
Dana D. Dlott

Author(s):  
Amir Nasrollahi ◽  
Piervincenzo Rizzo

This article presents a numerical formulation and the experimental validation of the dynamic interaction between highly nonlinear solitary waves generated along a mono-periodic array of spherical particles and rails in a point contact with the array. A general finite element model of rails was developed and coupled to a discrete particle model able to predict the propagation of the solitary waves along a L-shaped array located perpendicular and in contact with the web of the rail. The models were validated experimentally by testing a 0.9-m long and a 2.4-m long rail segments subjected to compressive load. The scope of the study was the development of a new nondestructive evaluation technique able to estimate the stress in continuous welded rails and eventually to infer the temperature at which the longitudinal stress in the rail is zero. The numerical findings presented in this article demonstrate that certain features, such as the amplitude and time of flight, of the solitary waves are affected by the axial stress. The experimental results validated the numerical predictions and warrant the validation of the nondestructive evaluation system against real rails.


Author(s):  
Hamid Bagheri ◽  
Daniel Vahidi

Gas turbine packages provide a major portion of mechanical drive and power supply for the offshore operating oil and gas platforms. These packages are typically installed in acoustic enclosures, which need to be ventilated for both removing the heat rejected from the engine and package components, and properly diluting explosive gasses in case of a leak. Considering importance of safety and reliability of gas turbine equipment operating in the offshore environment, and also near industrial and populated areas, authors of the paper emphasize the need for experimental validation of a CFD prediction practice for effective ventilation of the turbine package enclosures. In a properly designed acoustic enclosure, ventilation system has to prevent overheating of the electrical and engine control components, as well as, dilution of potential fuel leakages to eliminate stagnant zones that could cause an ignition within enclosure. Conversely, an excessive flow of the vent air may result in masking local fuel leakages, which might pass undetected through explosion protection devices. Therefore, the optimum enclosure ventilation design has to be based on proper vent flow distribution to ensure acceptable temperature distribution within the enclosure, proper flow distribution to ensure no stagnation area, combined with appropriate gas detection setting. In order to achieve an optimum enclosure design, rather complex flow and heat transfer phenomena have to be studied to select the optimal configuration of the vent system. Numerical analysis of the enclosures with commercially available CFD codes is usually based on a number of simplifying assumptions and approximations. Therefore, to satisfy critical safety requirements in the offshore environment, authors of the paper emphasize role of experimental validation of the CFD predictions. The presented paper provides details of the enclosure design validation using a CFD study based on an earlier experimental validation of the numerical predictions. A midsize gas turbine package model was selected to demonstrate this procedure. The main features from the actual engine package were included in the CFD model. Effectiveness of ventilation was studied for both cold and heated engine surfaces. CFD analyses were also carried out for local CO2 injection emulating natural gas leakage. Both scenarios with CO2 and natural gas (methane) leakages were considered reducing uncertainty of predictions due to the differences in the density and buoyancy between these gasses. Based on presented study certain improvements in design of the enclosure were recommended and described in the paper.


2015 ◽  
Vol 53 (01) ◽  
Author(s):  
L Spomer ◽  
CGW Gertzen ◽  
D Häussinger ◽  
H Gohlke ◽  
V Keitel

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