Computational Fluid Dynamics ( CFD) Modeling and Simulation

Using CATIA V5 design software a model was designed on the platform of Unmanned Combat Aerial Vehicle (UCAV).Computational Fluid Dynamics (CFD) Analysis was performed on the ANSYS Workbench 14.0(Fluent) of the UCAV. The Design was particularly done for low speed and high Angle of Attack (AOA) criteria. Important results were interpreted such as lift, drag and lift to drag ratio for various AOA which eventually leads to determining stall angle of the UCAV. Primitively stall angle of the UCAV is found to be 30 degrees and the lift to drag ratio as 7.63, thus making UCAV to have high stall angle at lower speeds. 100-120m/s are taken for lower speed phenomena, density of air being constant at 1.22 kg/m 3 .

- Nowadays, simulations through CFD technique is incorporated much earlier in the development stage of an automotive headlamp. Thereby, the automotive industries are able to produce an innovative and creative design with an enhanced performance standard within a reasonable time. The process of physical testing and its validation is available late in the development stage and are also very costly to be performed. Therefore, it is of great significance to simulate the risks during the design phase of the headlamp and henceforth, reduce the cost involved by carrying out proper thermal management studies through numerical analysis and simulations. The present study carries out an experimental analysis on a spherical automotive headlamp to determine the thermal characteristics and behaviour. Numerical analysis done through CFD technique is utilized to validate the experimental results. Thereby, showcase a simulation strategy using CFD methodology to determine the airflow and temperature distributions within a headlamp design. The methodology presents a fair agreement with the experimental and numerical analysis results

In present study, the effect of attack angles of triangular ribs in a two-dimensional microchannel has been numerically studied using finite volume method. The cooling fluid was water-Ag nanofluid at the range of 0-4% nanoparticles volume fraction and nanoparticle diameters of 25, 50 and 75 nm. Nanofluid flow considered to be laminar with Reynolds numbers equal to 5, 100 and 500. Also, attack angles were studied in a range of 30o to 60o. In this study, the effects of attack angle variation of triangular ribs, volume fraction of nanoparticles, nanoparticles diameter and Reynolds number have been investigated. The results indicate that using nanoparticles with the smaller diameter improves heat transfer rate. Moreover, coefficient of friction and pumping power are almost independent from nanoparticle diameters. Although, the influence of ribs is approximately insignificant on streamlines in low Reynolds numbers; it has a great effect in high Reynolds numbers. Using the triangular ribs with higher attack angles has an impressive heat transfer enhancement due to high velocity gradients and better mixing of fluid flow.

The modeling of two-phase flows has always been limited to special cases due to the very complex nature of its interface. When considering vertical pipe flows with low gas volume flow rates, bubbly flow occurs. With increasing gas volume flow rates larger bubbles are generated by bubble coalescence, which further leads to transition to slug, churn-turbulent, and annular flow. Considering, as an example, a heated tube producing steam by evaporation, as in the case of a vertical steam generator, all these flow patterns including transitions are expected to occur in the system. Despite extensive attempts, robust and accurate simulations approaches for such conditions are still lacking. This paper summarizes the state-of-the-art on the understanding of the physics behind churn-turbulent flow, and transitions to and from this flow pattern. Both, benefits and limitations of the existent experimental approaches and their usefulness for model development and validation at these high void fraction conditions are discussed. Limitation of both, low-dimensional approaches (0D, 1D, and 2D), and high resolution approaches such as Direct Numerical Simulations (DNS) are analyzed. Averaging procedures, such as the Eulerian-Eulerian approach including the interfacial momentum closures which has been used in the past for simulating churn flow, are review thoroughly. Finally, possible improvements are proposed.

Most of the fossil fuel & Cement Plant waste heat based thermal power plants are facing the problem of Boiler Super Heater tube leakage due to high flue gas Temperature. This will affect the working of power plant and income in general. The research is to study boiler super heater tube leakage problem and find the causes of tube leakages with the help of Computational Fluid Dynamics simulation. An Auto CADD 2-D modeling of super heater is performed and Import to Computational Fluid Analysis software where the temperature of flue gases over the Super Heater Tubes using the actual boundary conditions has been studied. The Computational Fluid Dynamics results will be useful for to avoid the same in future projects and can be avoid the leakage in already running the Thermal Power plants with providing the Shield arrangement over the critical zone of super heater tubes to reduce the erosion and restricting Super Heater Tubes

The present study explores nanofluid magnetohydrodynamics (MHD) natural convection in an incinerator shaped enclosure including a rectangular hot block situated on the bottom wall. A parametric investigation is conducted to explore the effect of different parameters such as nanoparticles volume fraction (ϕ=0-4%), Rayleigh number (Ra=10 3-10 5), external magnetic field intensity (Ha=0-100), incinerator tilting angle (γ=0-360°) and hot block's height (0.1-0.5), width (0.1-0.8) and position on heat transfer, nanofluid flow, and entropy generation inside the incinerator. The top and bottom horizontal walls of enclosure are adiabatic; the right, left vertical and inclined walls are supposed to have cold temperature whereas the hot block is maintained at a hot temperature. The Brownian motion was also considered in calculating the effective nanofluid thermal conductivity and viscosity using Koo-Kleinstreuer-Li (KKL) correlation. The

The objective of the presented work is to develop an efficient and validated approach based on a multi-dimensional computational fluid dynamics (CFD) code for predicting turbulent gaseous dispersion, conjugated heat and mass transfer, multi-phase flow, and combustion of hydrogen mixtures. Applications of interest are accident scenarios relevant to nuclear power plant safety, renewable energy systems involved in hydrogen transport, hydrogen storage, facilities operating with hydrogen, as well as conventional large scale energy systems involving combustible gases. All model development is conducted within the framework of the high-performance scientific computing software GASFLOW-Multi-Physics-Integration (MPI). GASFLOW-MPI is the advanced parallel version of the GAS-FLOW sequential code with many newly developed and validated models and features. The code provides reliability, robustness and excellent parallel scalability in predicting all-speed flow-fields associated with hydrogen safety, including distribution, turbulent combustion and detonation. In the meanwhile, it has been well verified and validated by many international blind and open benchmarks. The recently developed combustion models in GASFLOW-MPI code are based on the transport equation of a reaction progress variable. The sources consist of turbulence dominated and chemistry kinetics dominated terms. Models have been implemented to compute the turbulent burning velocity for the turbulence controlled combustion rate. One-step and two-step models are included to obtain the chemical kinetics controlled reaction rate. These models, combined with the efficient and verified all-speed solver of the GASFLOW-MPI code, can be used for simulations of deflagration, detonation and the important transition processes like flame acceleration (FA) and deflagration-to-detonation-transition (DDT), without additional need for expert judgment and intervention. It should be noted that the major goal is to develop a reliable and efficient numerical tool for large-scale engineering analysis, instead of resolving the extremely complex physical phenomena and detailed chemistry kinetics on microscopic scales. During the course of this development, new verification and validation studies were completed for phenomena relevant to hydrogen-fueled combustion, such as shock wave capturing, premixed and DOI of original article: http://dx. ScienceDirect j o urn al h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x (2 0 1 7) 1 e2 3 Please cite this article in press as: Xiao J, et al., GASFLOW-MPI: A new 3-D parallel all-speed CFD code for turbulent dispersion and combustion simulations, International Journal of Hydrogen Energy (2017), http://dx.

Filling of an empty cryogenic vessel initially at atmospheric temperature with a cryogenic liquid at its saturation temperature will initiate a high temperature difference between the terminals of the annular space containing the thermal insulating material. This high temperature difference is behind the dependence of thermal properties of the thermal insulation material on its temperature. Based on the authors’ own research and classroom experience, this book contains two parts, in Part (I): the 1D cylindrical coordinates, non-linear partial differential equation of transient heat conduction through a temperature dependent thermal conductivity of a thermal insulation material is solved analytically using Kirchhoff’s transformation. In Part (II): the 2D body-fitted coordinates, non-linear partial differential equation of transient heat conduction through a temperature dependent thermal properties of a thermal insulation material that is subjected to a natural convection heat transfer boundary condition associated with a periodic change in ambient temperature and heat flux of solar radiation is simulated numerically using the fully implicit Finite Volume Method

In the present study, the effect of triangular, rectangular and trapezoidal ribs on the laminar heat transfer of water-Ag nanofluid in a ribbed triangular channel under a constant heat flux was numerically studied using finite volume method. Height and width of ribs have been assumed to be fixed in order to study the effect of different rib forms. Modeling were performed for laminar flow (Re=1, 50 and 100) and nanofluid volume fractions of 0, 2% and 4%. The results indicated that an increase in volume fraction of solid nanoparticle leads to convectional heat transfer coefficient enhancement of the cooling fluid, whereas increasing the Nusselt number results in a loss of friction coefficient and pressure. Also, along with the fluid velocity increment, there will be an optimal proportion between heat and hydrodynamic transfer behavior which optimizes performance evaluation criteria (PEC) behavior. Among all of the investigated rib forms, the rectangular one made the most changes in the streamlines and the triangular form has the best thermal performance evaluation criteria values. For all studied Reynold numbers, heat transfer values are least for rectangular rib from. Therefore, trapezoidal ribs are recommended in high Reynold numbers.

In the present study, laminar flow and heat transfer of nanofluid water/single-wall carbon nanotubes have been investigated in a novel design of double layered microchannel heat sink (MCHS). Present investigation has studied the dimensionless values of truncated lengths (k) of 0, 0.4, 0.8 and 1. Studied Reynolds numbers were 500, 1000 and 2000. The effect of volume fraction of nanoparticles in the Newtonian suspension of water based nanofluid was studied for values of 0, 0.04 and 0.08. The results showed that the thermal resistance and ratio of maximum and minimum temperature difference for bottom wall of microchannel as well as the ratio of thermal resistance decrease by increasing the nanopar-ticles volume fraction and decrement of k. The Performance evaluation criteria (PEC) factor on the bottom of channel increases in all ratios of k by augmenting volume fraction of nanoparticles.

Nano-fluidic flow and heat transfer around a horizontal cylinder at Reynolds numbers up to 250 are investigated by using weakly compressible smoothed particle hydrodynamics (WCSPH). To be able to simulate enhanced nanoparticle heat transfer, this manuscript describes for the first time a development that allows conductive and convective heat transfer to be modelled accurately for the Eckert problem using WCSPH. The simulations have been conducted for Pr = 0.01–40 with nanoparticle volumetric concentrations ranging from 0 to 4%. The velocity fields and the Nusselt profiles from the present simulations are in a good agreement with the experimental measurements. The results show that WCSPH is appropriate method for such numerical modelling. Additionally, the results of heat transfer characteristics of nano-fluid flow over a cylinder marked improvements comparing with the base fluids. This improvement is more evident in flows with higher Reynolds numbers and higher particle volume concentration.().,-volV) (0123456789().,-volV)

With a change in EU-legislation regarding the dimensions
of heavy trucks [1] coming up, specifically allowing aerodynamic
devices fitted to the back of trailers, the transportation
industry is set to largely decrease its environmental
impact in the near future. These aerodynamic devices have
been researched for quite some time [2] but have not yet
gained widespread market acceptance, partly because of
the transportation industry’s complex owner structures and
partly because of size regulations of the past. Though with
this new legislation and other expected new EU-legislation
on CO2 emissions, development of these aerodynamic devices
looks set to become a field of intense study.
The study explores different options regarding the in-
fluence of changing the rear shape of a generalized ground
transportation system (GTS), a simplified model of a truck
geometry. By changing the rear shape the drag force induced
by the oncoming air flow was reduced, and the overall
coefficient of drag (CD) value lowered. There is also an
investigation as to how an added suction slot, and that slots
location, affects the CD.
Computational Fluid Dynamics (CFD) in the form of
the commercial computer software STAR-CCM+ was used
to simulate the flow around the GTS, and the results were
verified with similar studies and experiments [3] on the
same geometry. RANS equations and Menter k-ω SST turbulence
model was used for all simulations.
The results show that CD can be lowered by 21% compared
to a baseline case. Further on the added suction
slots can reduce drag, but depending on slot location also
can add to the drag force experienced by the GTS.

We present a numerical investigation of tapered arteries that addresses the transient simulation of non-Newtonian bio-magnetic fluid dynamics (BFD) of blood through a stenosis artery in the presence of a transverse magnetic field. The current model is consistent with ferro-hydrodynamic (FHD) and magneto-hydrodynamic (MHD) principles. In the present work, blood in small arteries is analyzed using the Carreau-Yasuda model. The arterial wall is assumed to be fixed with cosine geometry for the stenosis. A parametric study was conducted to reveal the effects of the stenosis intensity and the Hartman number on a wide range of flow parameters, such as the flow velocity, temperature, and wall shear stress. Current findings are in a good agreement with recent findings in previous research studies. The results show that wall temperature control can keep the blood in its ideal blood temperature range (below 40˚C) and that a severe pressure drop occurs for blockages of more than 60 percent. Additionally, with an increase in the Ha number, a velocity drop in the blood vessel is experienced.

A numerical study is carried out to investigate the effect of the addition of winglet to the end of blade on the axial fan performance. Validation and assessment of the used computer program FLUENT 6.2, is carried out by comparing its result with previous researcher. Simulation is then carried out to analyze the flow pattern with and without a winglet attached to the fan blade. Velocity distribution produced numerically showed that the winglet suppresses the secondary flow at the tip gap. Pressure distributions also confirmed the winglet advantages. Calculated performance of the fan used showed general increase of the fan efficiency with 3.5% above those without winglet at the optimum efficiency point and with up to 6 % at off design point.

In this study, 3D numerical simulation of rectangular small buildings having same plan area and height but different side ratio were carried out. The simulation was carried out in ANSYS CFX. For the simulation purpose, two different turbulence models (Standard K-Epsilon and Shear Stress Transport (SST)) are used. At the end, comparison of Pressure Coefficient (PCOE) results obtained from numerical simulation using CFD approach and the experimental results have presented. Also variation of turbulent kinetic energy obtained in numerical study is plotted for both turbulence models.

This paper studied wind-driven natural ventilation in a room using computational fluid dynamics model in order to determine the airflow pattern, draft and pollutant dispersion within the CFD model. The different natural ventilation strategies were studied in cases namely: CASE 1(Single sided ventilation), CASE 2(Cross Ventilation), CASE 3(Bernoulli and Cross Ventilation) and CASE 4(Double single sided ventilation). The CFD simulation was performed with the 3D steady state RANS approach using RNG-KE turbulent model to provide closure. From the result obtained, the author found out that Firstly, CASE 1 and CASE 4 showed a reduce level of air draft (V< 0.2m/s) within the room unlike the CASE 2 and CASE 3 where the air speed on the room occupants most especially at the ankle and head region were much higher than that recommended as per BS EN 7730. Secondly, CASE 2 showed greater efficiency in dealing with pollutant dispersion then followed by CASE 3 and CASE 4 respectively. The concentrations in almost every part of the room for CASE 2 were well within the acceptable range recommended for human occupancy as per BS EN 7730.

Coandă effect can be found in virtually all aerodynamic applications, and has drawn renewed interest for various applications, among others for generating lift and maneuvering impulses to be applied for unmanned air vehicles (UAV) and micro air vehicles (MAV). These air vehicles have the potential to revolutionize our sensing and information gathering capabilities, in homeland security and environmental areas. Sophisticated unmanned air vehicles for general applications have been developed rapidly across many different industries and interested researchers. In order to carry out a task, these air vehicles have to face many different challenges, due to the MAVs small size, flight regime, and modes of operation. This has led to the development of novel platforms that move away from traditional aircraft design in order to make them more capable. A good example is the Coandă MAV which uses the Active flow control-Coandă Effect. Improved aerodynamic performance of these air vehicles can lead to fast take off and slower landing speeds that can be related to reduce noise and crash survivability issues. The investigation and research in this field is rapidly rising and there are many concepts currently being considered around the world. This report provides an overview on the state of unmanned air vehicle and introduces the techniques of Active Flow Control ACF that could be potentially used for control of UAV. Furthermore, this paper may also focuses on the review research involved with the design modification and the generated flow phenomena of Micro air vehicle MAV.

This study evaluated the exergy analysis of the mechanical forced draft counter flow of the Port Harcourt Refinery cooling towers. The exergy analysis was carried out using the exergy destruction method. The results of the investigation and optimization show that the exergy destruction increases with the increases in mass flow rates of the cooling water, makeup water, and Air. Also, exergy destruction decreases with the decreases in Humidity Ratio, Heat sink Temperature, and Relative Humidity of Air. The optimal values of exergy efficiency of (0.7899[-]) and exergy destruction of (42135[W]]) obtained gave the expected minimum values of mass flows rates of Air (2185kg/s), Makeup water (79.33 (kg/s) and cooling water (4781 (kg/s).

This paper presents an account of model design, steady state simulation and a CFD analysis of three heat exchangers namely, double pipe heat exchanger, shell and tube heat exchanger and transverse fin type heat exchanger in order to evaluate their performance under a common parameter. The objective of this research work is to select the appropriate heat exchanger for exchange of excess heat from a liquid rheostat which controls the speed of an AC motor coupled to the fans of an open circuit wind tunnel. Five models in each of the three heat exchangers were designed and its pressure drop was calculated. This helped in determining the best model for further analysis. Each model from the three heat exchangers was analysed and parameters like temperature, pressure and velocity were compared. I. INTRODUCTION A wind tunnel is an aerodynamic test facility. It is mostly used to study flow patterns around bodies and measure aerodynamic forces on them. The bodies (called models) are usually scaled down but geometrically similar versions of bodies of interest like an airplane or an automobile. The results from wind tunnel tests can be 'scaled' to the actual velocity and actual body size using suitable scaling laws. A typical wind tunnel consists of a test section in which the model is kept, a contraction section and settling section before the test section, and a diffuser after the test section. A fan after the diffuser creates the wind. The function of the motor in the wind tunnel is to supply the necessary torque to the fan which will convert the torque into useful thrust. This thrust, which acts as a pressure difference at the fan station, has to supply the various losses encountered by the moving mass of air across the passage of the tunnel. A heat exchanger is a device that is used to transfer thermal energy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. In heat exchangers, there are usually no external heat and work interactions. Typical applications involve heating or cooling of a fluid stream of concern and evaporation or condensation of single or multicomponent fluid streams. A major characteristic of heat exchanger design is the relative flow configuration, which is the set of geometric relationships between the streams.

The use of passive safety systems are more and more diffused in many technological fields. Natural circulation is probably one of the main phenomenon applied in this kind of systems: indeed, as known, by means of gravity and buoyancy forces, the fluids can circulate without any external power sources. In this paper, a preliminary analysis (also by comparisons between experimental tests and numerical simulations) of a natural circulation based loop (namely a natural circulation based facility installed at University of Genova) is presented. Starting from some experimental results, the data deriving from CFD loop simulations (both in steady and in unsteady conditions) are used for a first preliminary validation, mainly in order to have a computational tool reliable and able to computationally simulate motion inversions related phenomena. The physical inversions phenomena are very well reproduced also by the a simplified numerical 2D model of the loop, and the physical considerations related to the temperature and velocity fluctuations during the transient simulations, are in agreement with the well-known observations formulated by Welander on the basis of a simple point source analysis scheme.

In this paper, the Magneto hydrodynamics (MHD) mixed convection and entropy analysis by introducing a power law hybrid nanofluid in a wavy elbow-shaped cavity with a quarter circle hot block and a rotating cylinder is studied numerically. A Galerkin finite element method (GFEM) is employed to study a rotating adiabatic cylinder, which is surrounded by an elbow-shape cavity. This cavity is bounded to a wavy wall, which is placed at the top. All walls are isothermal except one horizontal wall which is set to be at a cold condition. The heat source is located in the lower corner of this specific geometry. To investigate the thermal and hydrodynamics behavior of such specific cavity the Nusselt (Nu) numbers are compared. Moreover, a comparison is devoted for different aspect ratios, the Hartmann number, the nanofluid volume fraction and the power law index for the elbow-shaped cavity. Results proved that the Nu number increases via increasing the power law index. It is also inferred that the clockwise rotation, enhanced the heat transfer rate. In addition, it is depicted that by increasing the aspect ratio (AR) the heat transfer rate increases. Also, the entropy generation is fully investigated for the current geometry for the above-mentioned parameters.

Uso da Modelação Computacional em Projetos Baseados no Desempenho: exemplo de aplicação na Casa da Música e Coliseu Porto. Introdução (apresentação). Introdução à modelação computacional de incêndios e evacuação de edifícios usando os aplicativos computacionais FDS/Pyrosim e Pathfinder 2016. Apresentação de caso de estudo na Casa da Música (sala Suggia e sala 2) e Coliseu Porto (apenas evacuação). Apresentação dos resultados obtidos e respectivas conclusões.

The present work is a numerical simulation of a turbulent free jet issuing from an axisymmetric orifice into quiescent air environment. The numerical simulation was carried out by solving the Reynolds Averaged Navier-Stokes equations using OpenFOAM. The standard two-equation k-ɛ eddy viscosity turbulence model was used to simulate the turbulent flow field in a three dimensional cylindrical domain. The numerical predictions are compared with experimental data in order to assess the capability/limitations of the turbulence model to reproduce the physics involved and the code using jet case examined in this work. The standard k-ɛ model predictions in terms of centre line mean velocity decay, spread rate, entrainment, self-similarity, turbulence intensities and Reynolds stress, are found to reproduce the physics of the jet flow and agree approximately with experimental data. New information such as evolution of turbulent kinetic energy budget, length scales and time scales is provided.

Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work
carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD
analysis which can be time consuming and costly. However, it is important that such mathematical
equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of
mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis.
Methodology; CFD software was used to simulate different models. Results were tabulated and graphically
presented. The investigated mathematical equations were programmed in a spreadsheet, for data entry.
Results and analysis; data obtained from the two methods were compared and differences were recorded.
Discussions were included explaining the possible reasons for the deviations that surfaced between the two
methodologies.
Conclusions; this analysis has shown that although mathematical equations are effective and simple tools
in producing results, the results may not reflect the actual physical conditions. The analysis showed that the
exhaust gas temperature outlet of a double pipe heat exchanger is actually higher than what were
calculated using mathematical equations, and therefore, more heat energy is available for recapturing.
k-epsilon RNG turbulence model was found to be the most suitable method in analyzing heat transfer in a
finned double pipe heat exchanger.

農作物生產過程遭受強風吹襲而造成損失，防風網的利用是一種低成本及施作簡易
之防災策略。本研究擬建立由計算流體力學(CFD) 評估最適化防風網架設條件，作為提
供農作物防風技術之參考依據。試驗結果顯示，試驗田區架設不同網目及高度之防風
網，由實測風速變化以驗證CFD 模擬能力，結果顯示CFD模擬值與實際風場通過防風網
之減弱趨勢相符，可準確掌握風速流場，做為評估防風網效能之有效工具。另由評估結
果，防風網最佳阻風有效長度，水平距離為防風網高度之6 倍，有效高度為防風網高度
之1.3 倍。另由實際防風網在颱風期間之阻風效果案例分析，以70%百吉網阻風率可將18
m s-1 最大陣風降至4 m s-1，防風效果顯著。

A comparison between numerical simulations and measurements of a six-blade Kaplan turbine is presented in order to determine an appropriate numerical setup for accurate and reliable simulations of Kaplan turbines. Values of discharge, torque and losses obtained by different turbulence models are compared to each other and to the measurements. Steady state simulations with various turbulence models tend to predict large errors at full discharge rate, which are the result of underestimated torque on the shaft and overestimated flow energy losses in the draft tube. The results were slightly improved with the curvature correction (CC) and Kato-Launder (KL) limiter of turbulence production. Transient simulations were performed with shear-stress-transport (SST) turbulence model, the scale-adaptive-simulation (SAS) SST model, and with zonal large-eddy-simulation (ZLES). Details about turbulent structures in the draft tube are illustrated in order to explain the reasons for differences in flow energy losses obtained by different turbulence models. The effects of advection schemes and mesh refinement were tested. It was shown that all of the transient simulations considerably improved results at full discharge rate. The largest improvement was achieved with the SAS SST and the ZLES models in combination with the bounded central differential scheme. In addition, it was shown that the ZLES model produced accurate results at all operating points, with discrepancy lower than 1%.

A numerical model based on computational fluid dynamics was used to simulate the effect of nonisothermal
conditions on melt flows in a multi-strand billet caster tundish. To start with, water was
used as the operating fluid in a one-third scale tundish to calculate the fluid flow and temperature
fields under isothermal and non-isothermal conditions. The model was then extended to the fullscale
tundish with molten steel as the operating liquid in order to simulate the conditions in a real
plant. It was observed that using step inputs of 10° and 23° for water and steel cases, respectively,
changed the fluid flow patterns significantly, more so at locations far from the inlet, due to stronger
buoyancy-driven natural convective flows. The temperature distribution and inclusion trajectories
within the tundish were also affected due to the presence of non-isothermal conditions.

In the context of GEN-IV heavy liquid metal-cooled reactors safety studies, the flow blockage in a fuel sub-assembly is considered one of the main issues to be addressed and one of the most important accidents for Lead Fast Reactors (LFR). In order to model the temperature and velocity field inside a wrapped fuel assembly under unblocked and blocked conditions, a detailed experimental campaign as well as 3D thermal hydraulic analyses of the fuel assembly are required.
The present paper is focused on the CFD modeling and preliminary computational analysis of the new experimental facility „Blocked‟ Fuel Pin bundle Simulator (BFPS) that will be inserted in the heavy liquid metal NACIE-UP (NAtural CIrculation Experiment-UPgrade) facility located at the ENEA Brasimone Research Center (Italy). The BFPS test section aims to carry out suitable experiments to fully investigate different flow blockage regimes in a 19-pin fuel bundle providing experimental data in support of the development of the ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator) LFR DEMO. The BFPS test section, LBE cooled, was conceived with a thermal power of about 250 kW and a wall heat flux up to 0.7 MW/m2, which are relevant values for a LFR. It consists of 19 grid-spaced electrical pins placed on a hexagonal lattice with a pitch to diameter ratio of 1.4 and a diameter of 10 mm.
The geometrical domain of the fuel pin bundle simulator was designed to reproduce the geometrical features of ALFRED, e.g. the external wrapper in the active region and the spacer grids.
Different modeling approaches (e.g. meshing, turbulence modeling, codes and users) in RANS, URANS and LES will be compared to each other. The pre-test analyses presented here will facilitate the post-test analysis of the experimental data expected in 2017-2018. These calculations were carried out by applying unambiguous boundary conditions. In addition conjugate heat transfer is also considered.
The comparison among different codes and turbulence models allows to make an overall assessment of different approaches to CFD modeling and simulation. ANSYS CFX, STAR-CCM+ and OpenFOAM simulations are compared to each other.

A truly universal system to optimize consumptions, monitor operation and predict maintenance interventions for internal combustion engines must be independent of onboard systems, if present. One of the least invasive methods of detecting engine performance involves the measurement of the exhaust gas temperature (EGT), which can be related to the instant torque through thermodynamic relations. The practical implementation of such a system requires great care since its torque-predictive capabilities are strongly influenced by the position chosen for the temperature-detection point(s) along the exhaust line, specific for each engine, the type of installation for the thermocouples, and the thermal characteristics of the interposed materials. After performing some preliminary tests at the dynamometric brake on a compression-ignition engine for agricultural purposes equipped with three thermocouples at different points in the exhaust duct, a novel procedure was developed to: (1) tune a CFD-FVM-model of the exhaust pipe and determine many unknown thermodynamic parameters concerning the engine (including the real EGT at the exhaust valve outlet in some engine operative conditions), (2) use the CFD-FVM results to considerably increase the predictive capability of an indirect torque-detection strategy based on the EGT. The joint use of the CFD-FVM software, Response Surface Method, and specific optimization algorithms was fundamental to these aims and granted the experimenters a full mastery of systems’ non-linearity and a maximum relative error on the torque estimations of 2.9%.

— Continuous research is going on exchanger design and development to fulfill the demand of power sector, refrigeration and air conditioning, chemical industry, nuclear sectors this lead to evolution of helical coil tube heat exchanger. Higher performance and compactness are primary requirements of heat and mass transfer devices hence researchers are endeavor towards heat enhancement techniques with reduction in size of heat exchanger. An attempt is made here to elaborate the effect of constructional feature on these parameters by experimentally and using CFD technique. From several studies of previous authors it has been noted that curvature ratio is most predominant factor in helically coiled tube that affect heat transfer characteristics, hence main objective behind present study is to investigate the effect different curvature ratio helical tubes on single phase fluid flow and convective heat transfer characteristics. CFD simulation and experimental analysis indicates that compactness i.e. surface area density increases with curvature ratios, it is observed that heat flux increase with increase curvature ratio but at the expense of pressure drop in helical tube.

The study simulated the airflow pattern, thermal comfort and occupational exposure to CO 2 under two ventilation modes using computational fluid dynamics (CFD). A wall supply diffuser was located at the floor level for the displacement ventilation case while the supply air diffuser was placed at the ceiling level for the mixing ventilation mode. The manikin served as a jet, exhaled air through the nostrils downward at an angle of 45 degrees below the horizontal line. The CO 2 species was modeled as a passive scalar transport convection-diffusion equation. From the result obtained, the mixing ventilation case showed a low level of CO 2 concentration than in the displacement ventilation case. Also, higher vertical temperature gradient was noticed in the displacement ventilation case as opposed to the mixing ventilation scenario. Lastly, the mixing ventilation case showed higher tendencies of local draft than displacement ventilation case.

Accelerator Driven Systems (ADS) seem to be a good solution for safe nuclear waste transmutation. One of the most important challenges for this kind of machine is the target design, particularly for what concerning the target cooling system. In order to optimize this component a CFD-based approach has been chosen. After the definition of a reference design (Be target cooled by He), some parameters have been varied in order to optimize the thermal-fluid-dynamic features. The final optimized target design has an increased security margin for what regarding Be melting and reduces the maximum coolant velocity (and consequently even more the pressure drops).

Robotic fish design (Biomimetic) is an upcoming research area in which undulation motion has its own set of parameters to decide its efficiency. To analyse its swimming efficiency several existing robotic models using undulation motion have been thoroughly studied and few critical parameters such as fin size, shape, flexibility of material, fin flapping rate etc., have been identified. After simulating the above critical parameters using a MATLAB based CFD tool, mainly to design prototypes for research purpose which concentrates on optimizing its swimming efficiency. Several combinations of critical parameters are discussed for robotic fish prototype design by identifying critical parameters and maximizing the swimming efficiency of robotic fish based on the above properties. The fin models have been tested using Matlab based CFD tool through simulation and the swimming speed, direction have also been tested for various models. An improved benchmark for designing robotic fish model is proposed in order to simplify selection of components, architecture, and cost involve.

The development of chemical reactor network (CRN) models to predict the NOx emissions is very important for the modern combustion system design. In this study, the new chemical reactor network models are constructed based on the computational fluid dynamics (CFD) to simulate the burning process of the industrial combustor. The boundary and the operating conditions used for these CRN models reflect the typical operating conditions of the industrial combustor. The global mechanism has been developed by GRI 3.0 in the UW chemical reactor code. For the reliability of the predictive models, the models were analyzed and compared to the experimental industrial combustor research.The results of the CRN application to predict the NOx emissions show very goodagreement with the experimental data from Korea Electric Power Research Institute. Finally, the CRN models have shown to be efficient estimating accurately NOx emissions with a very short response time.

In this study according to the challenges of the power generation industry and condensing losses of wet steam flow, the strategy of Nano-droplets injection in nucleation zone is used. The strategy as such have been adopted to reduce the condensing losses of the flow and increase the efficient energy of the steam turbine. In the first step, after performing the sensitivity analysis on the computational domain of the non-equilibrium condensation model, the results are validated with the experimental data. Also, the SST k-ω turbulence model is utilized to simulate the latency created by the presence of Nano-droplets in the created domain. In the second step, the measurement criterion for injection effects in different locations of the nucleation zone is defined as efficient energy. This energy for the steam turbine are calculated as the energy of flow between the cascade blade, which it has the lowest wet losses of liquid phase and the highest temperature, velocity and internal energy. Finally, based on the Modified case, the efficient energy parameters have been presented, which result in a decrease of approximately 45% 27.5%, 21.4% 44% and 18%, for the condensation losses, droplets radius size, liquid mass fraction, the erosion rate ratio and wetness losses, respectively. Additionally an increasing trend of 18.25% and 0.2% for the efficient energy and Mach number has been observed.

The project is about to design and analysis the aircraft wing using eagle wing pattern. The project is inspired from Aquila nipalensis (steepe eagle).the eagle uses is special ability of tucking its tip feathers of its wing to reduce the turbulence similarly apply the eagle wing pattern in the aircraft wing and check the efficient of the wing. The airfoil used for the analysis is NACA 0012 which is a symmetrical airfoil. This pattern in the aircraft wing is efficient than the normal wing. I.