Numerical Simulation on Solidification of Flow inside an Elliptical Pipe

2015 ◽  
Vol 799-800 ◽  
pp. 751-755
Author(s):  
Lan Li ◽  
Huan Ma ◽  
Feng Qi Si ◽  
Kang Ping Zhu
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Three Dimensional ◽  
Short Axis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Axis Direction ◽  
Lower Reynolds Number ◽  
Flow Through

The aim of this investigation is to study the characteristics of solidification of flow through an elliptical pipe and to avoid the solidification and blockage in the pipe. A three-dimensional model has been completed using the commercial fluid dynamics code, Fluent. Analyses under different conditions show that different factors affect the characteristics of solidification and heat transfer in the pipe. The lower Reynolds number is or the higher dimensionless wall temperature turns, the thicker the ice layer becomes, which will increase the risk of blockage. The thickness at the long axis direction will grow with the increase of ellipse aspect ratio while it turns out contrary at short axis direction.

scholarly journals Numerical Simulation of a Propeller-Type Turbine for In-Pipe Installation

2021 ◽  
Vol 83 (1) ◽  
pp. 1-16
Author(s):  
Oscar Darío Monsalve Cifuentes ◽  
Jonathan Graciano Uribe ◽  
Diego Andrés Hincapié Zuluaga
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hydraulic Efficiency ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mesh Independence ◽  
Using Data

In this work, a 76 mm diameter propeller-type turbine is numerically investigated using a parametric study and computational fluid dynamics. The three-dimensional model of the turbine is modeled using data available in the bibliography. A mesh independence study is carried out utilizing a tetrahedron-based mesh with inflation layers around the turbine blade and the pipe wall. The best efficiency point is determined by the maximum hydraulic efficiency of 64.46 %, at a flow rate of 9.72x10-3 m3/s , a head drop of 1.76 m, and a mechanical power of 107.83 W. Additionally, the dimensionless distance y+, pressure, and velocity contours are shown.

Numerical Simulation of the Aerodynamics and Aerothermal Heating for a Hypersonic Vehicle

2012 ◽  
Vol 429 ◽  
pp. 147-153
Author(s):  
Hai Yong Liu ◽  
Hong Fu Qiang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mach Number ◽  
Thermal Environment ◽  
Three Dimensional ◽  
Hypersonic Vehicle ◽  
Attack Angle ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model

A hypersonic forebody based on waverider and liftbody concept was presented. The configuration of a new hypersonic vehicle was designed by taking the configuration of X43A. Numerical simulation was conducted on the two-dimensional and three-dimensional models of the vehicle using CFD software of Gambit and Fluent. The effects of Mach number and attack angle on the aerodynamics and heat transfer were considered. The results of simulation investigation showed that: High compressed air was constrained beneath the pre-compressed surface of the forebody. The computational data on central cross section of the three-dimensional model for the vehicle was similar to that of the two-dimensional model. But great pressure gradient existed between the pre-compressed surface and side surface of the forebody which would lead to severe air leakage and pressure loss. The increasing of attack angle and Mach number enforced the stagnation of shock wave on the side walls of the engine. The thermal environment of the vehicle was deteriorated rapidly with increasing Mach number. But the viscous heating was overrated which lead to unbelievable high temperature. The software Fluent was more suitable to predict the aerodynamics than the heat transfer for hypersonic flow.

scholarly journals Research on Parametric Design of Hydraulic Retarder Based on Multi-Field Coupling of Heat, Fluid and Solid

2015 ◽  
Vol 9 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Kuiyang Wang ◽  
Jinhua Tang ◽  
Guoqing Li
Keyword(s):  
Numerical Simulation ◽  
Parametric Design ◽  
Design Method ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Field Coupling ◽  
Sequential Coupling ◽  
Fluid Coupling ◽  
Hydraulic Retarder

In order to optimize the design method and improve the performance of hydraulic retarder, the numerical simulation of multi-field coupling of heat, fluid and solid is carried out to hydraulic retarder, based on the numerical computation and algorithm of heat-fluid coupling and fluid-solid coupling. The computation models of heat-fluid coupling and fluid-solid coupling of hydraulic retarder are created. The three dimensional model of hydraulic retarder is established based on CATIA software, and the whole flow passage model of hydraulic retarder is extracted on the basis of the three dimensional model established. Based on the CFD calculation and the finite element numerical simulation, the temperature field, stress field, deformation and stress state are analysised to hydraulic retarder in the state of whole filling when the rotate speed is 1600 r/min. In consideration of rotating centrifugal force, thermal stress and air exciting vibration force of blade surface, by using the sequential coupling method, the flow field characteristics of hydraulic retarder and dynamic characteristics of blade structure are analysised and researched based on multi-field coupling of heat, fluid and solid. These provide the theoretical foundation and references for parametric design of hydraulic retarder.

A three-dimensional model for analyzing the effects of salmon redds on hyporheic exchange and egg pocket habitat

2009 ◽  
Vol 66 (12) ◽  
pp. 2157-2173 ◽  
Author(s):  
Daniele Tonina ◽  
John M. Buffington
Keyword(s):  
Fluid Dynamics ◽  
Hydraulic Conductivity ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Three Dimensional ◽  
Hyporheic Exchange ◽  
Dimensional Model ◽  
Dynamics Model ◽  
Three Dimensional Model ◽  
Channel Hydraulics

A three-dimensional fluid dynamics model is developed to capture the spatial complexity of the effects of salmon redds on channel hydraulics, hyporheic exchange, and egg pocket habitat. We use the model to partition the relative influences of redd topography versus altered hydraulic conductivity (winnowing of fines during spawning) on egg pocket conditions for a simulated pool–riffle channel with a redd placed at the pool tail. Predictions show that altered hydraulic conductivity is the primary factor for enhancing hyporheic velocities and dissolved oxygen content within the egg pocket. Furthermore, the simulations indicate that redds induce hyporheic circulation that is nested within that caused by pool–riffle topography and that spawning-related changes in hyporheic velocities and dissolved oxygen content could create conditions suitable for incubation in locations that otherwise would be unfavorable (reinforcing the notion that salmonids actively modify their environment in ways that may be beneficial to their progeny).

Three-Dimensional Numerical Analysis of Horizontal and Vertical Coalescence of Bubbles at Two Submerged Horizontal Orifices on the Wall

2019 ◽  
Author(s):  
Z. P. Li ◽  
L. Q. Sun ◽  
X. L. Yao ◽  
Y. Piao
Keyword(s):  
Numerical Simulation ◽  
Internal Pressure ◽  
Three Dimensional ◽  
Ventilation Rate ◽  
Smoothing Technique ◽  
Dimensional Model ◽  
Mesh Smoothing ◽  
Three Dimensional Model ◽  
Coalescence Time ◽  
Ventilation Rates

Abstract In the process of bubbling from two submerged adjacent orifices, bubbles coalescence becomes inevitable. But the study of the evolution and interaction of bubbles from submerged orifices is little, especially numerical simulation. In this paper, combined with mesh smoothing technique, mesh subdivision technique and the technique of axisymmetric coalescence and 3D coalescence, a three-dimensional model of bubbles coalescence at two submerged adjacent orifices on the wall is established by the boundary element method. Then, numerical simulations were carried out for horizontal and vertical coalescence before detachment. Finally, by changing the ventilation rate and the Froude number, the effects of different ventilation rates and buoyancy on the process of bubbles coalescence at two adjacent orifices were investigated. The results show that for horizontal coalescence, the effect of ventilation rate is more pronounced than buoyancy. As the ventilation rate increases or the influence of buoyancy is decreased, the amplitude of internal pressure fluctuation of the bubble decreases and the coalescence time decreases. For vertical coalescence, the effect of buoyancy is more pronounced than ventilation rate. With the influence of buoyancy is decreased, the vertical coalescence time is increased, the internal pressure of the bubble is decreased. The influence of ventilation rate is similar to that of horizontal coalescence.

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