scholarly journals Sealed and Delivered

1999 ◽  
Vol 121 (10) ◽  
pp. 63-65
Author(s):  
Ray Clark ◽  
Henri Azibert ◽  
Lanre Oshinowo
Keyword(s):  
Heat Removal ◽  
Mechanical Seals ◽  
Centrifugal Pumps ◽  
Innovative Design ◽  
Surface Design ◽  
Seal Design ◽  
Fluid Handling ◽  
Physical Experiments ◽  
Outer Pair ◽  
Computational Fluid Dynamics Cfd

Engineers at A.W Chesterton Co., Stoneham, MA, applied computational fluid dynamics (CFD) to a new model of their heavy-duty cartridge dual seal Chesterton's dual seal consists of two pairs of seal rings. Mechanical seals are widely used to prevent leakage from fluid-handling equipment such as centrifugal pumps and mixers. Outer pair rotates with the shaft; inner pairs are fixed and contain a channel for the barrier fluid. The seal confines process fluids to the areas on the left. Taper is visible along the lower edge of the inner seal rings and on the corresponding surface of the shaft covering. CFD images described in the article depict the axial circulation of the seal's barrier fluid for a typical untapered seal design and the improved circulation resulting from the tapered surface design. The change in flow patterns results in an improvement in heat removal, from 0.7 to 1.1 kW. In order to validate the accuracy of the CFD results, physical experiments were conducted in Chesterton's seal test laboratory, using a variety of flow rates, rotation speeds, and fluids. The seals that do incorporate the innovative design have performed well in the field, operating at cooler temperatures that should result in seal life at least 30 percent longer,

CFD Investigation of Thermal-Hydraulic Behaviors in Full Reactor Core for Sodium-Cooled Fast Reactor

2018 ◽  
Author(s):  
Jing Chen ◽  
Dalin Zhang ◽  
Suizheng Qiu ◽  
Kui Zhang ◽  
Mingjun Wang ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Power Distribution ◽  
Three Dimensional ◽  
Reactor Core ◽  
Heat Removal ◽  
The Core ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Removal System ◽  
China Experimental Fast Reactor ◽  
Full Core

As the first developmental step of the sodium-cooled fast reactor (SFR) in China, the pool-type China Experimental Fast Reactor (CEFR) is equipped with the openings and inter-wrapper space in the core, which act as an important part of the decay heat removal system. The accurate prediction of coolant flow in the reactor core calls for complete three-dimensional calculations. In the present study, an investigation of thermal-hydraulic behaviors in a 180° full core model similar to that of CEFR was carried out using commercial Computational Fluid Dynamics (CFD) software. The actual geometries of the peripheral core baffle, fluid channels and narrow inter-wrapper gap were built up, and numerous subassemblies (SAs) were modeled as the porous medium with appropriate resistance and radial power distribution. First, the three-dimensional flow and temperature distributions in the full core under normal operating condition are obtained and quantitatively analyzed. And then the effect of inter-wrapper flow (IWF) on heat transfer performance is evaluated. In addition, the detailed flow path and direction in local inter-wrapper space including the internal and outlet regions are captured. This work can provide some valuable understanding of the core thermal-hydraulic phenomena for the research and design of SFRs.

Optimisation Studies for an Efficient Aerodynamic Configuration of a Blended Wing Unmanned Aerial Vehicle

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
M.K. Padmanabhan ◽  
G. Santhoshkumar ◽  
Praveen Narayan ◽  
N. Jeevaraj ◽  
M. Dinesh ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Focal Point ◽  
Lift Coefficient ◽  
Innovative Design ◽  
Aerodynamic Efficiency ◽  
Payload Capacity ◽  
Aerial Vehicle ◽  
Computational Fluid Dynamics Cfd ◽  
The Cost ◽  
Long Endurance

There are various configurations and parameters that contribute to the Design of Unmanned Aerial Vehicles for specific applications. This paper deals with an innovative design of an unmanned aerial vehicle for a specified class of UAVs that require demands such as long endurance, minimized landing space with vertical take-off and landing (VTOL) capabilities. The focal point of this design is superimposing the high endurance blended wing design into tri-copter to address these parameters. The preliminary calculations are initially performed for the blended wing VTOL vehicle based on the required payload capacity and endurance. Superimposing the tri-copter will decrease the aerodynamic efficiency of the vehicle. Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical methods and algorithms to solve complex problems involving fluid flow which will effectively employed to reduce the cost and time during the conceptual and preliminary design stages. CFD analysis was carried out to estimate the major parameters like lift, drag, lift coefficient (CL) and drag coefficient (CD) for various Angle of Attack (AoA) for configurations of blended wing vehicle with and without tri-copter system in the cruise condition. Thus, the vehicle design and propulsion system is effectively optimized using this drag estimation.

Investigating barotrauma in juvenile salmon passing through a very low head turbine using response surface methodology

2021 ◽  
pp. 095440622110504
Author(s):  
Mehrshad Foroughan ◽  
Alireza Riasi ◽  
Amir Bahreini
Keyword(s):  
Chinook Salmon ◽  
Cfd Simulation ◽  
Geometrical Parameters ◽  
Innovative Design ◽  
Computational Costs ◽  
Water Turbine ◽  
Low Head ◽  
Computational Fluid Dynamics Cfd ◽  
Biological Performance ◽  
Riverine Fish

Although hydropower is a clean source of energy, in some cases, it can jeopardize the life of some species of riverine fish. Very Low Head (VLH) water turbine is an innovative design that aims at reducing the adverse effects of such hydroelectric facilities. In this research, two methodologies are integrated to investigate barotrauma in juvenile salmons passing through this particular turbine. First, to quantify barotrauma, we implement a method known as BioPA (Biological Performance Assessment) by combining the results of some laboratory experiments on juvenile Chinook salmon moving through a simulated turbine passage with the Computational Fluid Dynamics (CFD) simulation of the flow field in this environment. In the second part, we added surrogate-based modeling as a tool, which enabled us to study the effects of two geometrical parameters on the environmental performance of the VLH turbine with low computational costs. The results indicate a significant dependency between the installation angle of the VLH turbine and the severity of the barotrauma of this particular fish. In addition, further investigations suggest that the region near the middle of blades is the safest for fish in the case of decompression.

scholarly journals Using CFD Simulations to Guide the Development of a New Spray Dryer Design

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 932
Author(s):  
Timothy A. G. Langrish ◽  
James Harrington ◽  
Xing Huang ◽  
Chao Zhong
Keyword(s):  
Deposition Process ◽  
Operating Conditions ◽  
Feed Concentration ◽  
Cfd Simulations ◽  
Physical Experiments ◽  
Solids Concentration ◽  
Computational Fluid Dynamics Cfd ◽  
Higher Temperature ◽  
Drying System ◽  
Drying Chamber

A new spray-drying system has been designed to overcome the limitations caused by existing designs. A key feature of the approach has been the systematic use of Computational Fluid Dynamics (CFD) to guide innovation in the design process. An example of an innovation is the development of a box-shaped transitional feature between the bottom of the main drying chamber and the entrance to the secondary chamber. In physical experiments, the box design performed better in all three representative operating conditions, including the current conditions, a higher feed solids concentration (30% solids rather than 8.8%), and a higher inlet drying temperature (230 °C rather than 170 °C). The current conditions showed a 3% increase in yield (solids recovery) while the 30% feed condition improved the yield by 7.5%, and the higher temperature test increased the yield by 13.5%. Statistical analysis showed that there were significant reductions in the wall flux at the high solids feed concentration. The observed deposition in the box was primarily from the predicted particle impacts by an inertial deposition process on the base of the box, which underwent little degradation due to lower temperatures. There is therefore evidence that the box design is a better design alternative under all operating conditions compared with other traditional designs.

A CFD Application to Optimize T-Shaped Fins: Comparisons to the Constructal Theory’s Results

2006 ◽  
Vol 129 (3) ◽  
pp. 324-327 ◽  
Author(s):  
Giulio Lorenzini ◽  
Simone Moretti
Keyword(s):  
Heat Removal ◽  
Numerical Approach ◽  
Geometric Constraints ◽  
Constructal Theory ◽  
Thermal Exchange ◽  
Conductive Material ◽  
Simplified Approach ◽  
Powerful Approach ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

The problem of heat removal in energetic processes represents a big challenge especially because of the enhanced requirements of the modern industry. The thermal exchange systems therefore have to guarantee better performances in correspondence to ever more severe dimensional constraints. This paper shows a numerical approach, based on computational fluid dynamics (CFD) software, for the evaluation of the heat exchange performances of finned (straight fins) surfaces made of highly heat conductive material. The same geometric constraints assumed in a reference work were adopted. This research attempts to develop an easy-to-use method to face what was previously solved by the powerful approach of Bejan’s Constructal theory. The results obtained show a good agreement between CFD and the Constructal theory’s results, validating, therefore, the simplified approach proposed and encouraging its application to a broader variety of geometries.

Design of the Controller Cooling System of an Electric Vehicle

2014 ◽  
Vol 663 ◽  
pp. 213-217 ◽  
Author(s):  
M.M. Rahman ◽  
T.J. Hua ◽  
H.Y. Rahman
Keyword(s):  
Heat Transfer ◽  
Electric Vehicle ◽  
Cooling System ◽  
Removal Rate ◽  
Heat Removal ◽  
Developed Countries ◽  
Internal Resistance ◽  
Heat Transfer Fluids ◽  
Computational Fluid Dynamics Cfd ◽  
Forced Air

As an effort in reducing the dependency on fossil fuel, efforts have been gathered to develop electric vehicle (EV) for the past decades. Technology of electric vehicles (EV) has been initialized in developed countries. However, the latter have different geographical and environmental conditions. Therefore, the system of EV cannot be utilized directly in this country. The controller of an EV functions by utilizing a potentiometer; supplying a certain amount of voltage from the batteries to the motor by driver’s force applied to the acceleration pedal. This action generates a huge amount of heat due to the internal resistance of the controller (e.g. potentiometer). In order for an EV to operate at optimum condition, temperature of the controller has to be maintained at a certain limit. Hence an effective cooling system is required to be designed to fulfill the above condition. The objective of this paper is to present the design of the cooling system for the controller of an electric vehicle (EV). Two types of cooling system namely liquid cooled plate heat exchanger and forced air cooled finned structure are designed and evaluated to assess the behavior of heat transfer as well as effects of heat transfer fluids and cooling system material towards the heat removal rate. Simulation using Computational Fluid Dynamics (CFD) for both cooling systems has been carried out to have better understanding. CFD results are compared with some of the analytical results. The findings revealed that both systems are suitable to be implemented as EV controller cooling system in Malaysian Environment.

Stability Analysis of Mechanical Seals With Two Flexibly Mounted Rotors

1998 ◽  
Vol 120 (2) ◽  
pp. 145-151 ◽  
Author(s):  
J. Wileman ◽  
I. Green
Keyword(s):  
Dynamic Properties ◽  
Equations Of Motion ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fluid Film ◽  
Mechanical Seals ◽  
Stability Threshold ◽  
Seal Design ◽  
The Stability ◽  
Gyroscopic Effects

Dynamic stability is investigated for a mechanical seal configuration in which both seal elements are flexibly mounted to independently rotating shafts. The analysis is applicable to systems with both counterrotating and corotating shafts. The fluid film effects are modeled using rotor dynamic coefficients, and the equations of motion are presented including the dynamic properties of the flexible support. A closed-form solution for the stability criteria is presented for the simplifled case in which the support damping is neglected. A method is presented for obtaining the stability threshold of the general case, including support damping. This method allows instant determination of the stability threshold for a fully-defined seal design. A parametric study of an example seal is presented to illustrate the method and to examine the effects of various parameters in the seal design upon the stability threshold. The fluid film properties in the example seal are shown to affect stability much more than the support properties. Rotors having the form of short disks are shown to benefit from gyroscopic effects which give them a larger range of stable operating speeds than long rotors. For seals with one long rotor, counterrotating operation is shown to be superior because the increased fluid stiffness transfers restoring moments from the short rotor to the long.

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