THREE-DIMENSIONAL MODEL AND NUMERICAL SIMULATION OF HEAT TRANSFER IN AN ANISOTROPIC HELICAL SOLID-MASS WITH INNER HEAT SOURCE

Author(s):  
Xuefeng Wang ◽  
David F. Chao ◽  
Nengli Zhang
2015 ◽  
Vol 799-800 ◽  
pp. 751-755
Author(s):  
Lan Li ◽  
Huan Ma ◽  
Feng Qi Si ◽  
Kang Ping Zhu

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.


2012 ◽  
Vol 429 ◽  
pp. 147-153
Author(s):  
Hai Yong Liu ◽  
Hong Fu Qiang

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.


2015 ◽  
Vol 9 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Kuiyang Wang ◽  
Jinhua Tang ◽  
Guoqing Li

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.


2019 ◽  
Author(s):  
Z. P. Li ◽  
L. Q. Sun ◽  
X. L. Yao ◽  
Y. Piao

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.


2018 ◽  
Vol 40 (4) ◽  
pp. 34-40
Author(s):  
B.I. Basok ◽  
B.V. Davidenko ◽  
I.K. Bozhko ◽  
M.V. Moroz

By the three-dimensional model of heat transfer in the system "ground - horizontal ground heat exchanger - heat transfer agent", an analysis of the efficiency of the horizontal multi-loop heat exchanger, which is an element of the heat pump system, was carried out. Based on the results of numerical simulation, the time dependence of the heat transfer agent temperature at the outlet from the ground heat exchanger and the amount of heat extracted from the ground is determined. The results of calculations by the presented model are satisfactorily agree with the experimental data.


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