scholarly journals Performance Evaluation of the Electric Machine Cooling System Employing Nanofluid as an Advanced Coolant

2021 ◽  
Vol 5 (3) ◽  
pp. 53
Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Cooling System ◽  
Fluid Motion ◽  
Electric Machine ◽  
Ansys Fluent ◽  
Special Effects ◽  
Overall Performance ◽  
Cooling Jacket ◽  
3D Finite Element Method

In this paper, the overall performance of an electric machine cooling system was examined in terms of heat transfer and fluid flow. The structure of the cooling system was based on the cooling jacket method. The cooling jacket contains spiral channels surrounding the stator and end-windings of the electric machine. Al2O3-water nanofluid is used inside the channels as the cooling fluid. The concentration of nanoparticles and the geometric structure of the cooling system have special effects on both aspects of heat transfer and fluid flow. Therefore, in this paper, the overall performance of the cooling system was evaluated by considering these effects. This study compared the importance of heat transfer and fluid flow performances on the overall performance of the cooling system. Numerical analyses were performed by 3D computational fluid dynamics and 3D fluid motion analysis. The analyses were carried out based on the 3D finite element method using the pressure-based solver of the Ansys Fluent software in steady mode.

scholarly journals Numerical simulation of the flow into a circular pipe section

2019 ◽  
Vol 85 ◽  
pp. 02005
Author(s):  
Gelu Muscă ◽  
George Mădălin Chitaru ◽  
Costin Ioan Coşoiu ◽  
Cătalin Nae
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Fluid Motion ◽  
Experimental Tests ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Turbulent Airflow ◽  
Quantitative Results ◽  
Computational Fluid Dynamics Cfd ◽  
Unsteady Numerical Simulation

Computational Fluid dynamics (CFD) is the science that evolves rapidly in numerical solving of fluid motion equations to produce quantitative results and analyses of phenomena encountered in the fluid flow. When properly used, CFD is often ideal for parameterization studies or physical significance investigations of flow that would otherwise be impossible to replicate through theoretical or experimental tests. The aim of this paper is the study of the turbulent airflow and how the vortices formed in turbulent airflow are influenced by the evolution of the hydraulic characteristics of the fluid flow. Unsteady numerical simulation were performed using Reynolds Average Navier-Stokes (RANS) turbulence model adapted to conventional flow into a pipe with variable section which was implemented in the ANSYS FLUENT expert software.

scholarly journals HEAT TRANSFER AND FLUID FLOW INSIDE DUCT WITH USING FAN-SHAPE RIBS

2021 ◽  
pp. 1-7
Author(s):  
Ahmed Yousif
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Ansys Fluent ◽  
Flow And Heat Transfer ◽  
Pitch Ratio ◽  
Flow Through ◽  
Energy Equations ◽  
Heat Transfers ◽  
Meshing Process

A 2-D computational analysis is carried out to calculate heat transfer and friction factor for laminar flow through a rectangular duct with using fan–shape ribs as a turbulator. The types of rib shapes are imported on the heat transfer rate and fluid flow in heat exchangers. The present study makes use of fan-shaped ribs with two arrangements. The first arrangement was downstream fan–shape ribs (case 1) and upstream fan–shape ribs (case 2) is investigated. A commercial finite volume package ANSYS FLUENT 16.1 is used for solving the meshing process with continuity, momentum, and energy equations respectively to investigate fluid flow and heat transfer across the ribs surface. The Reynolds number (Re) range of (400 – 2250) with different relative roughness pitch (p/H= 0.17, 0.22, 0.27 and 0.32) at constant rib high (e/H). The results show that the heat transfers and friction increase with using ribs also, the results show that heat transfer Directly proportional to pitch ratio and Reynolds number. The Nusselt number enhancement by (12% -29%).    

Heat Transfer and Fluid Flow Characteristic of One Side Heated Vertical Rectangular Channel That Inserted Thin Metallic Wire

2020 ◽  
Author(s):  
Gota Suga ◽  
Tetsuaki Takeda
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
High Temperature ◽  
Natural Convection ◽  
Cooling System ◽  
Copper Wire ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Experimental Apparatus ◽  
High Temperature Reactor

Abstract A Very High Temperature Reactor (VHTR) is one of the next generation nuclear systems. From a view point of safety characteristics, a passive cooling system should be designed as the best way of a reactor vessel cooling system (VCS) in the VHTR. Therefore, the gas cooling system with natural circulation is considered as a candidate for the VCS of the VHTR. Japan Atomic Energy Agency (JAEA) is advancing the technology development of the VHTR and is now pursuing design and development of commercial systems such as the 300MWe gas turbine high temperature reactor GTHTR300C (Gas Turbine High Temperature Reactor 300 for Cogeneration). In the VCS of the GTHTR300C, many rectangular flow channels are formed around the reactor pressure vessel (RPV), and a cooling panel utilizing natural convection of air has been proposed. In order to apply the proposed panel to the VCS of the GTHTR300C, it is necessary to clarify the heat transfer and flow characteristics of the proposed channel in the cooling panel. Thus, we carried out an experiment to investigate heat transfer and fluid flow characteristics by natural convection in a vertical rectangular channel heated on one side. Experiments were also carried out to investigate the heat transfer and fluid flow characteristics by natural convection when a porous material with high porosity is inserted into the channel. An experimental apparatus is a vertical rectangular flow channel with a square cross section in which one surface is heated by a rubber heater. Dimensions of the experimental apparatus is 600 mm in height and 50 mm on one side of the square cross section. Air was used as a working fluid and fine copper wire (diameter: 0.5 mm) was used as a porous material. The temperature of the wall surface and gas in the channel were measured by K type thermocouples. We measured the outlet flow rate by hot-wire anemometer which is an omnidirectional spherical probe of diameter 2.5mm. The experiment has been carried out under the condition that a copper wire with a scourer model and a cubic lattice model were inserting into the channel.

A novel approach for modelling fluid flow and heat transfer in an Open Volumetric Air Receiver using ANSYS-FLUENT

Solar Energy ◽  
2020 ◽  
Vol 204 ◽  
pp. 246-255
Author(s):  
P. Sharma ◽  
L. Chandra ◽  
P.S. Ghoshdastidar ◽  
R. Shekhar
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Ansys Fluent ◽  
Flow And Heat Transfer ◽  
Novel Approach

INFLUENCE THE RIBS IN NEW MODEL OF CHANNEL PATH ON HYDRO-THERMAL PERFORMANCE IN SERPENTINE MINI- CHANNEL HEAT SINK

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-115-2-123
Author(s):  
Hind M. Mohammed ◽  
◽  
Basim H. Abood ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Traditional Model ◽  
Conventional Model ◽  
Ansys Fluent ◽  
Well Model ◽  
New Models ◽  
Overall Performance ◽  
The Difference ◽  
Good Agreement

The aim of the present study is to enhance of heat transfer in mini channel heat sink. To reach the target of this study a new models of mini channel heat sink is proposed the traditional model, model (A) and model (B). Both model (A, B) has straight serpentine mini channel heat sink with inlet at the center, the difference between them is that model(B) has ribs within channel, the diameter of ribs is 1 mm with distance between ribs 5mm. A 3D (ANSYS Fluent program) 2019R3 is used to obtain the numerical outcomes. A good agreement is found when compared the experimental outcomes from the literature review and the numerical results of the traditional model in the current study. Furthermore, the findings demonstrate that the formation of flow has a great impact on heat transfer, Though the model with serpentine straight channel improve the pressure drop, thermal resistance, Nusselt number and the distribution of temperature in the base of heat sink. The overall performance factor (OPF) for new models under study are superior than conventional model. In addition, the average OPF for model (A) is [1.43] and for model (B) is [1.33] as compared with traditional model. As well, model (A) is superior as compared with model (B) by 6.99 % due to the effectual uniformity in the base of heat sink and efficient OPF.

A PIV Study of Natural Convection Induced by Oscillating Thermal Gradients

2002 ◽  
Author(s):  
Y. Shu ◽  
M. Higgins ◽  
B. Q. Li ◽  
B. R. Ramaprian
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Simulations ◽  
Practical Importance ◽  
Fluid Motion ◽  
Thermal Conditions ◽  
Melt Processing ◽  
Velocity Measurements ◽  
Macro Scale ◽  
Flow Phenomena

Microscale fluid flow and mass transfer are of both fundamental and practical importance to the design of solidification systems for melt processing of materials. These microscale fluid flow phenomena are affected by the macroscopic bulk flow motion and heat transfer away from the solidification front. As a first step towards a systematic understanding of the interactions of the micro- and macro-scale phenomena, a miniature cavity of a few millimeters in size is considered, where an oscillating temperature gradient is established to simulate the driving force under perturbed solidification conditions typical of microgravity environments. Flow visualization and velocity measurements of the transient oscillating fluid motion under two sets of thermal conditions are conducted using the Particle Image Velocimetry (PIV) technique. These experimental results are used to validate numerical simulations carried out using a finite element based model, developed by the authors for the prediction of flows in microgravity environments. The visualized flow pattern and velocity measurements in the two test cases compare very well with the numerical simulations. The numerical model is now ready to be used as a reliable tool for understanding and predicting the structure of fluid flow and heat transfer in microgravity environments.

Numerical Simulation of Fluid Flow and Heat Transfer in the Advanced CANDU® Reactor Endshield Using ANSYS-CFX and Porous Media Approach

2008 ◽  
Author(s):  
Khairy Khair ◽  
Saleh Baset ◽  
Livia Dimitrov ◽  
Julian Millard
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Cooling System ◽  
Cooling Water ◽  
Design Feature ◽  
Normal Operation ◽  
Detailed Model ◽  
Current Design ◽  
Whole Space ◽  
Steel Balls

A distinguishing design feature of CANDU® nuclear reactors is the use of horizontal fuel channels housed in a horizontal vessel called the calandria vessel, which is made of stainless steel. The calandria vessel has two endshields (each consists of two tubesheets called calandria tubesheet and fuelling tubesheet), which provide supports for the fuel channels among other purposes. The two tubesheets of each endshield are joined by a series of stainless steels tubes called lattice tubes. The space within each endshield between the tubesheets and the outside of lattice tubes is filled with cooling water and carbon steel balls. Thus, the endshields provide shielding to reduce radiation reaching the fuelling machine vaults. Nuclear heat is generated within the endshields. Endshields also receive heat from the primary heat transport system by conduction through the fuel channel bearings, by conduction and radiation through the annular insulating gap for the lattice tubes, and by convection from feeder cabinet. Three finite volume models have been developed to simulate different aspects of the coupling between the fluid flow and thermal energy. In model 1, the whole space inside the endshield is modeled as double porous medium to represent the lattice tubes and the steel balls regions respectively. In model 2, the lattice tubes are modeled in details and a single porosity is used to model the space occupied by the steel balls only. This detailed model also predicts the temperature on the surface of the lattice tubes. The work presented in the paper shows that the results from both models are in good agreement. It also shows that the current design of the ACR® endshield cooling satisfies the design requirements with respect to the heat transfer to the shield cooling system during normal operation. Model 3 is used to predict temperature and flow behaviour under transient load service conditions.

Computational Fluid Dynamics Simulation Based Comparison of Different Pipe Layouts in an EATHE System for Cooling Operation

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Kamal Kumar Agrawal ◽  
Rohit Misra ◽  
Mayank Bhardwaj ◽  
Ghanshyam Das Agrawal ◽  
Anuj Mathur
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Capital Investment ◽  
Cooling System ◽  
Temperature Drop ◽  
Dynamics Simulation ◽  
Helical Coil ◽  
Ansys Fluent ◽  
Passive Technique

Earth air tunnel heat exchanger (EATHE) is a capable and quite simple passive technique which may be utilized for space cooling/heating using the constant temperature of underground subsoil. However, it could not gain much attraction as a heating/cooling system as it requires larger trench lengths to accommodate longer pipes. Larger trench lengths involve huge excavation cost and a sufficiently large piece of land. The length of the trench needed can be reduced substantially by adopting a proper pipe layout. In the present study, the performance of U-shaped, slinky-coil, and helical-coil pipe layouts of an EATHE system is compared numerically using ANSYS FLUENT 15.0. Results reveal that the temperature drop and heat transfer rate per unit trench length are higher in the slinky-coil pipe layout than in U-shaped and helical-coil pipe layouts. After 12 h of continuous operation, the effectiveness of the EATHE system with U-shaped, slinky-coil, and helical-coil pipe layouts is obtained as 0.60, 0.80, and 0.78, respectively. The study reveals that the selection of pipe layout for the EATHE system mainly depends on temperature drop EATHE is capable of giving, heat transfer rate, pumping power required, and ease of fabrication and installation as all these factors directly affect the initial and recurring capital investment for the EATHE system.

Heat Transfer and Fluid Flow Characteristics of One Side Heated Vertical Rectangular Channel Applied As Vessel Cooling System of VHTR

2018 ◽  
Author(s):  
Kenta Fujikami ◽  
Tetsuaki Takeda ◽  
Shumpei Funatani
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
High Temperature ◽  
Natural Convection ◽  
Porous Material ◽  
Cooling System ◽  
Flow Characteristics ◽  
High Porosity ◽  
High Temperature Reactor ◽  
Fluid Flow Characteristics

A Very High Temperature Reactor (VHTR) is one of the next generation nuclear reactor systems. From a view point of safety characteristics, a passive cooling system should be designed as the best way of a reactor vessel cooling system (VCS) in the VHTR. Therefore, the gas cooling system with natural circulation is considered as a candidate for the VCS of the VHTR. Japan Atomic Energy Agency (JAEA) is advancing the technology development of the VHTR and is now pursuing design and development of commercial systems such as the 300MWe gas turbine high temperature reactor GTHTR300C (Gas Turbine High Temperature Reactor 300 for Cogeneration). In the VCS of the GTHTR300C, many rectangular flow channels are formed around the reactor pressure vessel (RPV), and a cooling panel utilizing natural convection of air has been proposed. In order to apply the proposed panel to the VCS of the GTHTR300C, it is necessary to clarify the heat transfer and flow characteristics of the proposed channel in the cooling panel. Thus, we carried out an experiment to investigate heat transfer and fluid flow characteristics by natural convection in a vertical rectangular channel heated on one side. Experiments were also carried out to investigate the heat transfer and fluid flow characteristics by natural convection when a porous material with high porosity is inserted into the channel. An experimental apparatus is a vertical rectangular flow channel with a square cross section in which one surface is heated by a rubber heater. Dimensions of the experimental apparatus is 600 mm in height and 50 mm on one side of the square cross section. Air was used as a working fluid and fine copper wire (diameter: 0.5 mm) was used as a porous material. The temperature of the wall surface and gas in the channel were measured by K type thermocouples. The flow velocity distribution was obtained by a PIV method. In this paper, we discuss the heat transfer and fluid flow characteristics of the proposed channel. From the results obtained in the experiment, it was found that the amount of removed heat decreased with increasing of temperature of gas when a copper wire was inserted into the channel with high porosity. This is because the mass flow rate decreased with increasing of viscosity of gas. Since it is expected that the porosity of a porous material will have an optimum value, further studies will be needed.

Fluid Flow and Heat Transfer Simulations of the Cooling-Water Channel in a Tera-Hertz Radiation Detector

2012 ◽  
Author(s):  
Usama Tohid ◽  
Arturo Pacheco-Vega ◽  
Rodion Tikhoplav ◽  
Marcos Ruelas
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Laser Irradiation ◽  
Stokes Equations ◽  
Cooling System ◽  
Rectangular Channel ◽  
Operating Conditions ◽  
Channel Height ◽  
Flow And Heat Transfer ◽  
Direct Laser

Detailed numerical simulations have been carried out to find the velocity and temperature fields of a rectangular channel with large aspect-ratio. The channel under analysis is aimed to cool a thermo-chromic liquid crystal material (TLC) that is able to capture laser irradiation in the terahertz range. The overall objective of the cooling system is to maintain a nearly-homogeneous temperature of the TLC layer that is not exposed to the direct laser irradiation. The fluid flow and heat transfer simulations are carried out on the basis of three-dimensional versions of the Navier-Stokes equations, along with the energy equation, for an incompressible flow, to determine values of velocity, pressure and temperature inside the channel under different operating conditions. These values are then used to find, from a specific set, the value of the channel height that allows for the most uniform temperature distribution within the expected operating conditions. Results from this analysis indicate that, for all the inlet velocities considered, there is a common value of the channel height, that represents the optimum.

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