Computer Modeling of Non-Standard Fire Testing Using the Combination of Ansys Fluent and Ansys Mechanical Software

Chemical flooding with ionic liquid and nonionic surfactant mixture in artificially prepared carbonate cores: A diffusion controlled CFD simulation

Enhanced oil recovery potential analysis through simulation of a bio-based surfactant using CFD

The combustors are the direct-fired heaters or burners where the fuel burns in stoichiometric composition and evolves an enormous amount of heat for process heating. The natural gas combustor utilizes natural gas as fuel for the combustion process. Several designs of natural gas combustors are available for the above-said process; based on the application, the design of the combustor is determined. The current research is motivated towards the CFD simulation of natural gas combustor using Species Transport model along with different Turbulence models (Standard k − ℇ, Realizable k − ℇ, RNG k − ℇ, Standard k − ω and SST k − ω) and Radiation models (Discrete Ordinate (DO), P1 and Rosseland) in two different simulation tools (Ansys Fluent and Star CCM+). The flow, thermal and combustion analysis of natural gas combustor is performed with the above-mentioned combustion, radiation and turbulence models in Ansys Fluent. The results obtained from the simulation using Ansys Fluent are compared with the available experimental results of Sayre et al. (Scaling Characteristics of Aerodynamics and Low-NOx Properties of Industrial Natural Gas Burners, The SCALING 400 Study, Part IV: The 300 kW BERL Test Results. International Flame Research Foundation, The Netherlands, 1994, [1]) to validate the adopted methodology. The best-predicted turbulence and radiation model, along with the Species Transport model, is used in Star CCM+. The simulated results in both the software are compared with the experimental results and are in close agreement.

In recent years, large-scale structural fire testing has experienced something of a renaissance. After about a century with the standard fire resistance test being the predominant means to characterize the response of structural elements in fires, both research and regulatory communities are confronting the many inherent problems associated with using simplified single element tests, on isolated structural members subjected to unrealistic temperature-time curves, to demonstrate adequate structural performance in fires. As a consequence, a shift in testing philosophy to large-scale non-standard fire testing, using real rather than standard fires, is growing in momentum. A number of custom made, non-standard testing facilities have recently been constructed or are nearing completion. Non-standard fire tests performed around the world during the past three decades have identified numerous shortcomings in our understanding of real building behavior during real fires; in most cases these shortcomings could not have been observed through standard furnace tests. Supported by a grant from the Fire Protection Research Foundation, this paper presents a review of relevant non-standard structural fire engineering research done at the large-scale around the world during the past few decades. It identifies gaps and research needs based both on the conclusions of previous researchers and also on the authors’ own assessment of the information presented. A review of similar research needs assessments carried out or presented during the past ten years is included. The overarching objective is to highlight gaps in knowledge and to help steer future research in structural fire engineering, particularly experimental research at the large-scale.

With the advantages of the thermophysical property of supercritical carbon dioxide (SCO2), SCO2 has been proposed for being used as the coolant of the secondary system in a nuclear reactor to promote a higher thermal efficiency. However, heat transfer deterioration (HTD) in supercritical fluid became a potential operational problem for the supercritical heat exchanger. Understanding of HTD is importance to heat exchanger tube design. In this paper, both circular and annular tube with the same sectional area is simulated using the ANSYS FLUENT 15.0 with Shear Stress Transport (SST) turbulence model. In general, the SST model can accurately predict the position of HTD peak as found in the experiment but with a difference between the simulated and experimental value of the peak. Nevertheless, the SST model is still regarded as the turbulence model in modeling supercritical carbon dioxide heat transfer in ANSYS FLUENT. Computational Fluid Dynamics (CFD) simulation was performed for SCO2 on 8.42 MPa with an inlet temperature of 312.15K under heat flux value of 110 kW/m2 to illustrate the effect of heat transfer deterioration in the circular and annular tube. Second, the effect of turbulence augmentation to wall temperature are investigated by placing the semi-circular obstacles at the heated wall of the circular tube. The result showed that the addition of Vortex Generator (VG) could lessen the HTD effect and followed by the smoothing effect of the wall temperature along the downstream of the tube.

Two different computational fluid dynamic models for the combustion of species were applied for the study of the combustion of pulverized coal in a drop tube. The drop tube is available in the department of energy research of the technical university of Ostrava. The purpose of this work is to find out the main characteristics of the combustion of pulverized coal using data gathered at the laboratory where the drop tube is installed. Some characteristics studied were the total heat transfer involved in the combustion, highest temperature and pressure gradients. A 2d mesh of the drop tube was created in gambit pre-processor and the simulations were performed using the CFD program Ansys fluent. The simulations were performed with double precision (dp mode) in order to get accurate results. In order to simulate the pulverized coal combustion, it was necessary to study turbulence, turbulence models (RNG k-e), combustion models (species transport and non-premixed model) as the modeling in gambit and the setting up of a case in Ansys Fluent. The main goal was to get similar results in the simulations using distinct approaches (different methods of studying the combustion) in Ansys Fluent and the results were satisfying. The total amount of heat transfer results, for example, was quite similar in both experiences.

CFD based mass transfer modeling of a single use bioreactor for production of monoclonal antibody biotherapeutics

This paper presents the CFD analysis of performance investigation of sinusoidal corrugated absorber plate solar air heater (SAH). The thermal performance is investigated with various inlet mass flow rates and solar heat flux. Simulation process of this model is carried out using CFD base analysis using Ansys (fluent) software. Air heater involving sinusoidal absorber plate, baffles and fin are modelled by ANSYS Workbench. Base model CFD results are validated against published ones and found to have a good agreement. In this paper we compare thermal efficiency and temperature at the exit of sinusoidal absorber plate solar air heater with fin, baffles and without fin and baffles. Baffles help in creating recirculation, separation and turbulence zones in the flow passage and fin helps in increasing the net heat transferring area between sinusoidal plate and flowing air. Thus, for the same size as the air heater, thermal efficiency increases. Thermal efficiency increases with rise in mass flow rate and outlet temperature decrease with the increase in mass flow rate. Computations are based on FVM, shear stress transport (SST) k-ω turbulence model, and SIMPLE algorithm has been implemented. CFD tool is used to find out the temperature distribution inside the solar air heater.

This work compared the suitability of the k-ϵ standard, k-ϵ RNG, k-ω SST, and k-ω standard turbulence models for simulating a gravitational water vortex hydraulic turbine using ANSYS Fluent. This study revealed significant discrepancies between the models, particularly in predicting vortex circulation. While the k-ϵ RNG and standard k-ω models maintained relatively constant circulation values, the k-ϵ standard model exhibited higher values, and the k-ω SST model showed irregular fluctuations. The mass flow rate stabilization also varied, with the k-ϵ RNG, k-ω SST, and k-ω standard models being stabilized around 2.1 kg/s, whereas the k-ϵ standard model fluctuated between 1.9 and 2.1 kg/s. Statistical analyses, including ANOVA and multiple comparison methods, confirmed the significant impact of the turbulence model choice on both the circulation and mass flow rate. Experimental validation further supported the numerical findings by demonstrating that the k-ω shear stress transport (SST) model most closely matched the real vortex profile, followed by the k-ϵ RNG model. The primary contribution of this work is the comprehensive evaluation of these turbulence models, which provide clear guidance on their applicability to gravitational water vortex hydraulic turbine simulations.

최근 개정된 소방법은 성능위주 설계법을 도입하여 운영되고 있으며, 건축법 또한 성능위주 설계로의 전환이 시작되고 있다. 실물 화재실험은 규모와 환경에 대한 제약이 있고 많은 비용이 소요되므로 다양한 형태의 화재상황을 구현하기 위하여 시뮬레이션 기법을 이용하게 된다. 본 연구에서는 선행연구의 결과로 얻어진 단위공간의 실물화재실험 데이터를 바탕으로 각각의 공간에 대한 화재 시뮬레이션을 수행하였다. 공간별 화염성장속도, 열방출율(HRR), 총발열량(THR) 및 온도변화를 비교하였으며 비교 결과, 화염성장속도는 실물실험에 비해 수치해석이 약 12% 빠르게 성장하였고, 열방출율은 수치해석이 실물실험보다 평균 11% 정도 높게 나타났다. 총발열량은 다른 수치에 비해 실물실험과 열방출량의 차이가 크게 나타났으며, 실내 최고온도를 비교한 결과 수치해석이 실물실험에 비해 약 7% 가량 낮게 나타났다. A revised Korean Fire Code is operating based on performance design method and Korean Building Code has been also adopted to performance design method. A real fire scale test has some limitations of scale, environment and cost. For studying the variety of fire situations, we could use computer simulation method. In this study, computer simulation was performed for compartment fire based on data obtained real fire scale test of compartment. And we compared the real fire scale test data and simulation data for flame growth rate, heat release rate, total heat release and temperature. From the simulation results, the flame growth rate was over predicted of 12 percent, the heat release rate was over predicted of 11 percent, the total heat release was under predicted of 50 percent and the maximum temperature of compartment was under predicted of 7 percent than real fire scale tests.

Platelet transport in flowing blood is a critical issue in the prediction of thrombus formation. Since available data on platelet aggregation are essentially from experiments, the goal of this work is to investigate numerical solutions for platelet transport and predict the relative influence of convection and diffusion on platelet deposition at the arterial wall. The results obtained for laminar flow in an aneurysm show that both species transport and discrete phase models predict accurately the effects of convective and diffusive mechanisms and match experimental data closely. The species transport model also appears to estimate correctly platelet deposition in turbulent flow through a stenosis.

The performance of turbulence models was investigated to predict the flow and turbulence features of the vegetated channel using computational fluid dynamics (CFD). The Ansys Fluent, CFD software was implemented for the numerical studies. The flow was three-dimensional, incompressible, steady, and turbulent. Ten turbulence models, provided by Ansys Fluent, were implemented for the comparative study. The numerical model was validated against an experimental study conducted in the literature. The numerical studies show that the Renormalization group k–ε model is the most successful model for predicting the flow characteristics of the vegetated channel with a Root Mean Square Error (RMSE) value of 0.2752. At the same time, the Reynolds Stress Model gives the least successful predictive performance, indicated by an RMSE value of 0.4302. Moreover, the Spalart–Allmaras (S–A) model offers the shortest computation time with a value of 6652.393 s, whereas the Shear Stress Transport k–ω model proves to be the most time-consuming with a value of 11 952.219 s. The velocity of water flow in a channel is not uniform as it is slower at the surface of leaves and faster in the free zones. The maximum velocity is observed in the middle section of the channel, below the leaf, and between the roots with the value of u = 0.1158 m/s. Furthermore, the characteristics of turbulence in a channel are influenced by several factors such as channel geometry, flow velocity, and vegetation distribution. As a result, the presence of vegetation in a channel affects the flow and turbulence characteristics of the water significantly.

On account of ANSYS Classic, ANSYS Fluent and ANSYS CFX-Post external coupling a new approach for joined simulation of liquid metal flow, free surface dynamics and electromagnetic (EM) field in induction furnaces is developed. The model is adjusted for the case of EM levitation and extended on 3D consideration with application of standard k-ω Shear Stress Transport (SST) or précised Large Eddy Simulation (LES) turbulence description. Calculated steady state free surface shapes of molten metal are compared to other models and experimental measurements in traditional and EM levitation induction furnaces. Calculated free surface dynamics of melt is compared to analytical estimation of free surface oscillation period. Parameter studies performed in ICF and conventional EM levitation setup briefly illustrate capabilities of the model and demonstrate the influence of current, frequency, surface tension and viscosity on free surface dynamics and steady shape of the melt in 2D approximation. Finally, full 3D calculation of free surface dynamics in ICF using k-ω SST and LES turbulence models is performed and the impact of turbulence model on meniscus is discussed.

Investigation of vortex flow patterns at the meniscus in a water caster mould

<p>This M.Eng Report is a preliminary investigation of the strut geometry in a strut-based hydrogen scramjet combustor and assesses flow characteristics in an inviscid and viscid flow with no hydrogen injection, a viscid flow with hydrogen injection, and a viscid flow with hydrogen injection and combustion model. This investigation is performed using ANSYS Fluent. The viscid cases utilize the Shear Stress Transport (SST) k-omega model for turbulence, with the volumetric eddy dissipation model for combustion case. Results in this study are validated against the same wedge strut geometry and results from the Deutsches Zentrum für Luftund Raumfahrt (DLR) scramjet, by Waidmann [1], and a grid independence study is conducted for completeness. Performance of the different geometries are quantified by mixing efficiency, combustion efficiency, and total pressure recovery. The 2-dimensional results of this paper are comparable to the Schlieren images (shadow graphs) of the DLR combustor. </p> <p>The viscid case with no hydrogen injection is compared to the inviscid case with no hydrogen stream, resulting in the presence of boundary layers and shear layers. This increased the strength and quantity of shock/expansion wave reflections downstream of the strut. The addition of the hydrogen stream increased the thickness of the central wake region along the combustor, further increasing strength of the shock reflections, as well as creating a symmetric recirculation region downstream of the strut. The eddy-dissipation combustion model is applied, resulting in a larger, non-symmetric recirculation region. The combustion efficiency reached 78.42% with complete mixing at 245 mm along the combustor, whereas the non-combusting case achieved complete mixing at 225 mm along the combustor. The high entropy caused by the irreversible processes across several strong shocks in the combustion case attributed to a total pressure loss of 46%.</p>