Cooling Finite-element

TeGrotenhuis et al. studied a counter-current heat-exchanger reactor for the WGS reaction with integrated cooling gas channels for removal of the reaction heat. The computational domain of their 2-D model on the basis of the finite-element method... 

With the above-described heat transfer model and rapid solidification kinetic model, along with the related process parameters and thermophysical properties of atomization gases (Tables 2.6 and 2.7) and metals/alloys (Tables 2.8,2.9,2.10 and 2.11), the 2-D distributions of transient droplet temperatures, cooling rates, achievable undercoolings, and solid fractions in the spray can be calculated, once the initial droplet sizes, temperatures, and velocities are established by the modeling of the atomization stage, as discussed in the previous subsection. For the implementation of the heat transfer model and the rapid solidification kinetic model, finite difference methods or finite element methods may be used. To characterize the entire size distribution of droplets, some specific droplet sizes (forexample,.D0 16,Z>05, andZ)0 84) are to be considered in the calculations of the 2-D motion, cooling and solidification histories. 

In designing axi-symmetric shell structures such as large-type cooling towers, it is necessary to predict the vibration responses to various external forces. The authors describe the linear vibration response analysis of axi-symmetric shell structures by the finite element method. They also analyze geometric nonlinear (large deflection) vibration which poses a problem in thin shell structures causes dynamic buckling in cooling towers. They present examples of numerical calculation and study the validity of this method. 11 refs, cited. 

Basic elastic and geometric stiffness properties of the individual supporting columns are synthesized into a stiffness matrix compatible with an axisymmetrical shell element by a series of transformations. These are to be used in conjunction with a finite element representation of the cooling tower, where the displacements are decomposed into Fourier... 

A finite element method is employed to study the nonlinear dynamic effect of a strong wind gust on a cooling tower. Geometric nonlinearities associated with finite deformations of the structure are considered but the material is assumed to remain elastic. Load is applied in small increments and the equation of motion is solved by a step-by-step integration technique. It has been found that the cooling tower will collapse under a wind gust of maximum pressure 1.2 psi. 13 refs, cited. 

Strains and stresses were computed for the joined specimen cooled uniformly to room temperature from an assumed stress-free elevated temperature using numerical models described in detail previously [19, 20]. The coordinate system and an example of the finite element mesh utilized are shown in Figure 3. Elastie-plastic response was permitted in both the Ni and Al203-Ni composite materials a von Mises yield condition and isotropic hardening were assumed. 

Mouldings are usually designed so that the melt flows from thicker into thinner sections, to ensure that the extremities are fed properly. A two-dimensional heat flow calculation illustrates a problem that can arise during solidification. Figure 6.12a shows isotherms for the cooling of a rib, with a heat transfer coefficient of 1000Wm K at the mould interface, calculated by finite element analysis. The thinner rib solidifies first, and an isolated island of melt, cut off from the melt supply, is left at the intersection of the rib and the plate. Contraction of this melt either causes sink marks in... 

Heat transport and after heat remouval for gas-cooled reactors under accident conditions". The CEA is involved in a benchmark which is a code to experiment comparaison between JAERI HTTR experiment and french calculations - These calculations were made with a finite elements method 3D code (TRIO-EF) which is a general code. With it, it is possible to have conduction, convection and radiation heat transfer coupled. 

Sudret B., Defaux G., and Pendola M. 2005. Ilme-invariant finite element reliability analysis application to the durability of cooling towers. Structural Safety, 27,93-112. 

The reactor can be assumed to be a two-dimensional axi-symmetric vessel so any vertical section taken through the vessel will have the same flow pattern [5-9]. Strictly, this will only apply if there are no internal mechanical components. If baffles or internal cooling coils are used it is necessary to use a full three-dimensional model [10-12]. Unfortunately, this adds considerably to the computational effort to obtain a solution. For the case considered here a computational technique based on the use of finite elements is used to solve the flow and heat transfer equations so that a wide variety of vessel geometries can be examined. 

Likewise, when engineering battery packs for satellites, one does not have the benefit of convection, either forced or natural, as a cooling mechanism. Using our models, we can predict the heat dissipated, and with the addition of finite element software, study the temperature distribution in cells under different cycling protocols and cooling scenarios. 

Figures 5.6 and 5.7 show 3D and 2D finite element mesh generation schemes of a prestressed concrete vessel designed for a high-temperature gas-cooled reaetor. Both internal and external loads have been computed in accordance with the method given in Chapter 3. The program CREEP, which...

Plate AIB.l Gas ducts, cooling pipes, control rods and other penetractions with finite element mesh schemes... 

In any computer package involving 2- and 3D finite-element technique, Table AIB.l giving analytical formulation can be simulated to analyse the liner between the studs, standpipes and cooling pipes. For the global analysis of the pressure and containment vessels, these local effects can form the worst case. The vessel can be analysed with and without the contribution of the liner. Under ultimate conditions the liner local areas must be thoroughly assesed prior to the final decision of the factor safety above the elastic conditions under (pressure + prestress + temperature) the combined loading ... 

A step-by-step analysis is given for the direct computation of 2D heat flow and safe pitching of the cooling pipes. Two models of the cooling system have been selected and calculations have been carried out for an existing vessel. On the one model this analysis is compared with the 3D finite-element analysis for obtaining insulation conductance for various cooling pipes. A safety factor is established. 

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