scholarly journals CFD Technique to calculate tube skin peak temperatures in refinery furnaces

2011 ◽  
Vol 4 (4) ◽  
pp. 73-88
Author(s):  
Fabian A. Diaz ◽  
Jesús A. Castro

Tube skin peak temperature is one of the major parameters in furnaces operation since they determine the life of the tubes and the extent of an operation run. This parameter is very difficult to calculate appropriately in magnitude and location within the furnace and commercial furnace simulators usually fail in its calculation. Computational fluid dynamics (CFD) is the only technique that calculates peak skin temperatures with great precision and accuracy since radiation and convective heat fluxes can be calculated taking into account every singularity of the geometry of the furnace and the burners. In this work is developed a technique to calculate this parameter using CFD commercial code (Ansys Fluent) and an in-house furnace simulator (EcoFursim), results of the simulations are compared with data from different furnaces from Barrancabermeja refinery (Barrancabermeja, Colombia) and good agreement is observed. Refinery furnace is referred in this paper to fired heaters for non reacting heat up of hydrocarbons or petroleum crude.

Author(s):  
D. Dupleac

The paper overviews the analytical studies performed at Politehnica University of Bucharest on the analysis of late phase severe accident phenomena in a Canada Deuterium Uranium (CANDU) plant. The calculations start from a dry debris bed at the bottom of calandria vessel. Both SCDAPSIM/RELAP code and ansys-fluent computational fluid dynamics (CFD) code are used. Parametric studies are performed in order to quantify the effect of several identified sources of uncertainty on calandria vessel failure: metallic fraction of zirconium inside the debris, containment pressure, timing of water depletion inside calandria vessel, steam circulation in calandria vessel above debris bed, debris temperature at moment of water depletion inside calandria vessel, calandria vault nodalization, and the gap heat transfer coefficient.


2020 ◽  
Vol 10 (20) ◽  
pp. 7032 ◽  
Author(s):  
Pucciarelli Andrea ◽  
Galleni Francesco ◽  
Moscardini Marigrazia ◽  
Martelli Daniele ◽  
Forgione Nicola

The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident (PLOFA). The facility consists of an internal loop, equipped with a fuel pin simulator and a steam generator, and an external pool. In this coupling application, the System code RELAP5 is adopted for the simulation of the internal loop while the CFD code ANSYS Fluent is used for the sake of simulating the pool. The connection between the two addressed domains is provided at the inlet and outlet section of the internal loop; a thermal coupling is also performed in order to reproduce the observed thermal stratification phenomenon. The obtained results are promising and a good agreement was obtained for both the mass flow rates and temperature measurements. Capabilities and limitations of the adopted coupling technique are discussed in the present paper also providing suggestions for improvements and developments to be achieved in the frame of future applications.


2012 ◽  
Vol 220-223 ◽  
pp. 1698-1702
Author(s):  
Jian Chen ◽  
Zhu Ming Su ◽  
Qi Zhou ◽  
Jian Ping Shu

A novel hydraulic rotary high speed on/off valve is investigated. The function of the outlet turbine and the effect on revolution speed of valve spool are analyzed. The inner fluid flow condition under full open case of the on/off valve is simulated using computational fluid dynamics(CFD) method based on Ansys/Fluent and velocity and pressure profiles of fluid inside valve are obtained. Suggestions on optimizing the geometry of valve to decrease transition losses are given.


Author(s):  
Yang Liu ◽  
Yihao Zheng ◽  
John Pitre ◽  
William Weitzel ◽  
Joseph Bull ◽  
...  

Arteriovenous fistula is the joining of an artery to a vein to create vascular access for dialysis. The failure or maturation of fistula is affected by the vessel wall shear stress (WSS), which is difficult to measure in clinic. A computational fluid dynamics (CFD) model was built to estimate WSS of a patient-specific fistula model. To validate this model, a silicone phantom was manufactured and used to carry out a particle imaging velocimetry (PIV) experiment. The flow field from the PIV experiment shows a good agreement with the CFD model. From the CFD model, the highest WSS (40 Pa) happens near the anastomosis. WSS in the vein is larger than that in the artery. WSS on the outer venous wall is larger than that on the inner wall. The combined technique of additive manufacturing, silicone molding, and CFD is an effective tool to understand the maturation mechanism of a fistula.


2014 ◽  
Vol 1044-1045 ◽  
pp. 422-425 ◽  
Author(s):  
Yan Jie Wang ◽  
San Ping Zhou

In the operation process of permanent magnet governor, the temperature rises due to eddy current loss, and demagnetization of permanent magnet occurs at high temperature. The numerical simulation of fluid flow field and temperature field was carried out with the method of computational fluid dynamics (CFD) and ANSYS-Fluent software. And then we improved the structure of permanent magnet governor on the basis of analysis of the flow field and temperature distribution. The result indicates that the flow of improved structure increases, and temperature drops 46.°C, fulfilling the desired temperature range of permanent magnet can bear, which provides a theory basis for the design of ventilation-cooling structure of permanent magnet governor.


2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Elin Yusibani ◽  
Hidayatun Nisa ◽  
Rajibussalim Rajibussalim

Penelitian ini bertujuan untuk mensimulasikan distribusi temperatur dengan variasi radius channel garam dan temperatur masukan pada teras Molten Salt Breeder Reactor (MSBR). Computational Fluid Dynamics (CFD) dengan perangkat lunak Ansys Fluent digunakan pada simulasi ini untuk sebuah sel moderator. Variasi radius channel garam adalah 0,0108 m; 0,0208; dan 0,0308 m dengan panjang moderator 3,96 m. Variasi temperatur masukan adalah 809 K, 839 K, 859 K, dan 909 K. Hasil simulasi pada variasi radius menunjukkan bahwa dengan pertambahan sebesar 0,01 m memberikan kenaikan suhu sebesar 8 - 23 K pada temperatur masukan konstan. Perubahan terhadap temperatur masukan, diperoleh kenaikan temperatur keluaran antara 1 - 10 K, pada radius channel garam yang konstan. Dengan demikian dapat disimpulkan bahwa distribusi temperatur dalam teras MSBR akan meningkat jika radius channel garam diperkecil atau temperatur masukan dinaikkan.


2019 ◽  
Vol 19 (3) ◽  
pp. 345-447
Author(s):  
Luong Ngoc Loi ◽  
Nguyen Chi Cong ◽  
Ngo Van He

In this work, the commercial Computational Fluid Dynamics (CFD), ANSYS-Fluent V.14.5 has been used to illustrate the effects of rudder and blade pitch on hydrodynamic performances of a propeller. At first, the characteristic curves of a container ship propeller are computed. Then, effects of rudder on hydrodynamic performances of the propeller in the both cases of the propeller with and without rudder have been investigated. The relationships between the blade pitch angle and the hydrodynamic performances of the selected referent propeller in this work having designed conditions as diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m and the boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller, pressure distribution, velocity distribution around propeller and the efficiency of the propeller have been shown. From the obtained results, the effects of rudder and blade pitch angle on hydrodynamic performances of the propeller have been evaluated.


2019 ◽  
Vol 286 ◽  
pp. 07006
Author(s):  
A. Agriss ◽  
M. Agouzoul ◽  
A. Ettaouil

The idea behind this work comes from the question: What is the impact of plate corrugations on drag? In this context, a numerical study of laminar incompressible flow over a flat plate and over corrugated plates is carried out. Numerical analysis is performed for low Reynolds numbers (Re= 10, Re = 50, Re = 100, Re = 500, Re =1000) using the computational fluid dynamics (CFD) software ANSYS FLUENT. Simulations results are compared to each others and with those of the reference plate (flat plate (figure 4a)). Comparisons are made via drag coefficient Cd. This work is the beginning of a study that evaluates the impact of corrugations on drag reduction on a flat plate.


Author(s):  
Anwar Alsulami ◽  
Muhammad Akbar ◽  
Woong Yeol Joe

This paper presents an aerodynamics study of wing morphing by creating a Computational Fluid Dynamics (CFD) model using ANSYS FLUENT. First, known National Advisory Committee for Aeronautics (NACA) 2410 and 8410 profiles of airfoils are modeled. Models are run using prescribed initial and boundary conditions to simulate the morphed wing and flow around it. The Shear Stress Transport (SST) k–ω turbulence model is used to obtain an accurate comparison with the analytical results. Once satisfied with validation, variable cambers between NACA 2410 and 8410 are used in two ends of a wing to mimic a morphed wing situation. Drag and lift coefficients are analyzed for this configuration to understand effects of the airfoil shape on aerodynamic performance. A refined mesh is created near the airfoil wall to capture the flow details. This study is a step forward towards understanding how to accurately model the dynamic morphing of an airplane wing.


Author(s):  
Shingo Yamanaka ◽  
Takayuki Hirai ◽  
Yasunori Nihei ◽  
Akira Sou

Advanced spar type of the floating wind turbine with a short spar and a cylindrical column floater has been developed and tested recently. However, numerical methods to accurately simulate the interaction between the advanced spar and waves have not been established yet. In this study we simulated the free surface flow around an advanced spar in regular waves using open source computational fluid dynamics (CFD) software OpenFOAM to examine its applicability. We used olaFOAM which equipped with the functions to set the boundary conditions of wave generation at the inlet and wave absorption at the exit. An experiment of the advanced spar model fixed in space in the regular waves with various wave periods was also conducted to obtain an experimental database on the horizontal and vertical forces acting on the structure and pressure distribution on the floater surface. The results of the forces obtained by the numerical simulation, experiment, Morison’s equation were compared to examine the validity of the numerical model. Numerical and experimental results of the horizontal and vertical forces as well as pressure distribution on the floater surface were in good agreement, which confirmed the validity of the present numerical method. Then, we evaluated numerically the effects of the edge of the column by simulating a sharp-edged and a chamfered column floater. The result clarified that a chamfered edge decreased the wake which reduced the forces acting on the floater structure.


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