scholarly journals A New Method Solving Contact/Detach Problem in Fluid and Structure Interaction Simulation with Application in Modeling of a Safety Valve

2010 ◽  
Vol 2010 ◽  
pp. 1-15
Author(s):  
Zheng Guo
Keyword(s):  
Experimental Data ◽  
Unstructured Grid ◽  
Safety Valve ◽  
Grid Cell ◽  
Blocking Effect ◽  
Structure Interaction ◽  
Wall Boundary Condition ◽  
Computation Process ◽  
Valve Opening ◽  
Interaction Simulation

A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.

Hydrodynamic Loads Calculation of Pressurizer Safety Valve Discharge Piping Using RELAP5/MOD3.1 Computer Code

2003 ◽  
Author(s):  
Kyu Bok Lee ◽  
Heedo Lee ◽  
Jae Sik Jeung ◽  
Hee Jin Ko ◽  
Chang Hyo Kim
Keyword(s):  
Experimental Data ◽  
Input Data ◽  
Safety Valve ◽  
Computer Code ◽  
Design Tool ◽  
Hot Water ◽  
System Component ◽  
Hydrodynamic Loads ◽  
Calculation Results ◽  
Valve Opening

An assessment was performed with RELAP5/MOD3.1 computer code for EPRI/CE Test No. 917 which was a simulation of a hot water loop seal discharge followed by steam discharge through a pressurizer safety valve. In the RELAP5/MOD3.1 calculation, the input data such as valve opening characteristics, initial fluid conditions, system nodalizations, and system component modeling, were modeled to be identical to those in the RELAP5/MOD1 calculation performed by EPRI. In addition, the input data such as options applied to volumes and junctions, heat transfer to the pipe walls, and pipe orientations, were modeled in accordance with the modeling guidelines suggested in NUREG/IA-0093 which was a RELAP5/MOD3/5m5 code assessment for EPRI/CE Test No. 917. The calculation results were compared with the experimental data as well as the RELAP5/MOD1 calculation to assess the applicability of the RELAP5/MOD3.1 for the hydrodynamic loads calculation. It was demonstrated from the comparisons that the RELAP5/MOD3.1 computer code yielded very similar hydrodynamic loads to the experimental data as well as the RELAP5/MOD1 calculation results, even though minor discrepancies were also identified. Therefore, it is concluded from the assessment that the RELAP5/MOD3.1 computer code can be used as a suitable design tool to calculate the hydrodynamic loads for the hot water loop seal discharge followed by steam discharge transient.

Single Phase CFD Inside a Water Safety Valve

2010 ◽  
Author(s):  
Christophe Vallet ◽  
Je´roˆme Ferrari ◽  
Jean-Franc¸ois Rit ◽  
Fe´de´ric Dehoux
Keyword(s):  
Experimental Data ◽  
Single Phase ◽  
Safety Valve ◽  
Three Dimensional ◽  
Flow Coefficient ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Water Safety ◽  
Relief Valve ◽  
Valve Opening

In this paper, Computational Fluid Dynamics (CFD) modeling is used to improve the understanding of the liquid flow inside a safety valve and to predict both the hydraulic force acting on the disk and the flow coefficient Cv. The three-dimensional simulations are performed on a realistic geometry and with an unstructured hybrid mesh. Independent calculations are performed for several valve openings. Turbulence is simulated using the Reynolds-Averaged Navier-Stokes (RANS) model k – ω SST, and a single-phase flow is considered for simplification. First, sensitivity of results with boundary conditions and mesh fineness is analysed. The dependence of hydraulic parameters with the valve opening is then investigated and numerical results are compared to experimental data coming from a test rig reproducing industrial conditions. Results indicate firstly that the flow inside the valve is stationary and axisymmetric. Quantitative comparison with the experiment must account for cavitation which is not simulated. We show, however, the adequacy of our results with experimental data and that single phase CFD can provide valuable insights on cavitating relief valve flow.

Hydrodynamic Loads Calculation of Pressurizer Safety Valve Discharge Piping Using RELAP/SCDAPSIM

2018 ◽  
Author(s):  
S. Jiang ◽  
Z. Fu ◽  
J. K. Hohorst
Keyword(s):  
Experimental Data ◽  
Safety Valve ◽  
Hot Water ◽  
Force Balance ◽  
System Component ◽  
Structural Elements ◽  
Hydrodynamic Loads ◽  
Balance Calculation ◽  
Calculation Results ◽  
Valve Opening

The hydrodynamic loads are very important for the discharge piping design because of the fast opening of the valves and the presence of liquid in the upstream loop seals. Therefore, this work implemented a force balance formulation into the RELAP/SCDAPSIM code to determine the hydrodynamic loads directly. The force balance method, which equates resultant force transmitted from fluid to structural elements as the sum of all pressure and frictional tractions acting on the wetted surface of the element. Then an assessment was performed with RELAP/SCDAPSIM code for EPRI/CE Test No.917, which was a simulation of a hot water loop seal discharge followed by steam discharge through a pressurizer safety valve. In the RELAP/SCDAPSIM calculations, the input data such as valve opening characteristics, initial fluid conditions, system Nodalization, and system component modeling, were based on original RELAP5/MOD1 and RELAP5/MOD3 calculations performed by EPRI. The calculation results were compared with the experimental data as well as the RELAP5/MOD1 and RELAP5/MOD3 calculation to assess the applicability of the RELAP/SCDAPSIM for the hydrodynamic loads calculation. It was demonstrated from the comparisons that the RELAP/SCDAPSIM code with force balance calculation yields very similar hydrodynamic loads to the experimental data as well as the RELAP5/MOD1 and RELAP5/MOD3 calculation results. Therefore, it is recommended that the new force balance calculation implemented in RELAP/SCDAPSIM can be used to calculate the hydrodynamic loads for the hot water loop seal discharge followed by steam discharge transient.

scholarly journals Fluid–structure interaction simulation on flight performance of a dragonfly wing under different pterostigma weights

2021 ◽  
Vol 37 ◽  
pp. 216-229
Author(s):  
Yung Jeh Chu ◽  
Poo Balan Ganesan ◽  
Mohamad Azlin Ali
Keyword(s):  
Optimization Design ◽  
Fluid Structure Interaction ◽  
Spatial Location ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Dragonfly Wing ◽  
Interaction Simulation ◽  
Wing Performance ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract The dragonfly wings provide insights for designing an efficient biomimetic micro air vehicle (BMAV). In this regard, this study focuses on investigating the effect of the pterostigma weight loading and its spatial location on the forewings of dragonfly by using the fluid–structure interaction simulation. This study also investigates the effect of change in the wing elasticity and density on the wing performance. The forewing, which mimics the real dragonfly wing, is flat with a 47.5 mm span and a 0.4 mm thickness. The wing was set to cruise at 3 m/s with a constant flapping motion at a frequency of 25 Hz. This study shows that a small increase of pterostigma loading (11% of wing weight) at the tip of the wing significantly improves the lift to drag ratio, CL/CD, which has 129.16% increment in comparison with no loading. The lift to drag ratio depends on the pterostigma location, pterostigma loading, elastic modulus and density. The results of this study can be used as a reference in future BMAV wing optimization design.

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