Aimed at the methodology of package heat transfer analysis, this paper presents a simple computation model for the thermoflow simulation of a module PBGA package mounted on printed circuit board that is bonded in a compact box of air cooling. Having been validated by comparing computational results of temperature rise with experimental ones, the model is applied to the heat transfer analysis of the package model. The correlations of thermal resistance with system parameters have been investigated. Computational results show that the thermal resistance decreases with the increase of mean flow velocity and it has a local minimum value corresponding to the height of clearance between the substrate and the box bottom under a relative strong forced convection.

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In this paper, viscoplastic constitutive model for deformation of Pb free solder alloys was proposed. FEM analysises of microelectronics solder joints was also conducted using the viscoplastic constitutive model. For the FEM analysis, basic experiments, such as pure tension, cyclic loading and creep tests were conducted using Sn-3.5Ag-0.75Cu solder alloy at several tests conditions. As a result, it was found that the thermal deformation of the solder alloy was successfully simulated by the FEM analysis, into which the constitutive model was incorporated.

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The results of numerical simulation of the hollow cylinder which is subjected to uniform steady flow are shown. The simulation is carried out about the downstream cylinder of the tandem arrangement. In the simulation the measured flow pressures on the surface of the cylinder are applied to calculate the distortion and the displacement of the cylinder. The measured pressure consists of fluctuationg and steady components, the former one is asssumed to be a harmonic functiuon.

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This paper presents a numerical method to predict residual stress and shape of tempered glass for automotive. The glass is assumed as a thermorheologically simple viscoelastic material and structural relaxation effects of glass are considered in the calculation of transient stress. The numerical results of residual stress in tempered glass agree well with the experimental results. The present method is applicable to forming process of automotive glass in non-isothermal condition.

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A new approach to represent the non-slip boundary condition in the lattice-Boltzmann method (LBM) was proposed to improve the resolution for flow in the vicinity of solid wall. Considering the velocity distribution function as a volumetric average in each lattice, the solid boundary was taken into account in the convection process, not in the collision process as in the previous method. Then we applied it to the driven flow in a square cavity of Reynols number up to 7500 and a direct numerical simulation of turbulent flow in a plane channel at Reynolds number 300 based on friction velocity. The wall-limiting profile of velocity was significantly improved by our method in comparison with previous ones. We believe our proposal could contribute to develop an applicability of LBM for higher Reynolds number flows.

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Both a computer language (e.g., FORTRAN) and a solution methodology have to be learned to conduct the numerical analysis for fluid flow and heat transfer. If the numerical computation can be carried on a spread-sheet software (e.g., EXCEL), the understanding of the solution methodology is only required for the learners. This may bring the benefit for engineers and/or students who want to learn or to conduct the numerical analysis for fluid flow and heat transfer. The main objective of this study is to investigate whether the numerical analysis for fluid flow and heat transfer is possible on the spread sheet software. In this study, one-dimensional numerical analysis for the compressive flow in a shock tube are conducted with using EXCEL and the possibility is examined.

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Moderator Temperature Coefficient is defined as the reactivity change per unit moderator temperature change. The measured moderator temperature and reactivity signals have noise. In order to estimate moderator temperature coefficient correctly, elimination of signal noise is important. From this point of view, wavelet transform analysis is known as an effective method. A basic idea of reactivity coefficient estimation is that the analyzed reactivity component is divided by the analyzed component of the relevant parameter. We carried out numerical simulations of moderator temperature coefficient measurement by using wavelet transform and good results were obtained. Using this method we estimated moderator temperature coefficients for measurement data in actual reactors. The results have proved that the method is applicable for estimation of moderator temperature coefficients in the actual reactors. It is expected to reduce the required data length during the measurement. We expect to estimate the other reactivity coefficients with the data of short transient.

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To make paper web by drainaging water component from pulp and filler suspension, some hydrofoils are mounted under the wire forming section of paper machine. We developed a simple model to simulate a part of this sheet forming section area. In this paper, we indicate the simulation results of a sheet formation process using this model, that is, slurry consistency, slurry thickness and pulp mat thickness variations that is piled up gradually on the wire and drainage flow rate etc. Regarding to pulp slurry thickness, we compared it with actual measurement by using ultrasonic distance sensor. Furthermore utilized this calculation result we inter its sheet structure that is made by each hydrofoil-blocks and filler content distribution along sheet thickness direction.

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Glass fiber reinforced plastics have been widely used as electric insulators in the form of hollow tube. GFRP is the material of the combination of light weight and high strength. The matrix resin is polymer, they may absorb moisture and break the insulation of inner elecric devices. In order to evaluate the amount of moisture permeation into the inner part, Finite element program was developed. Steady and transient moisture permeation up to 30 years were calculated. The result shows that total amount of moisture permeation can be reduced by aging composite insulators at moderate temperature.

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Diffusion of dioxin class into the environment has become one of serious social problems. More than 80% of such dioxin class is estimated to be discharged from trash incinerators and factories. There are several ways to solve the problems, In this study, we focus on the quantitative understanding of dioxin class diffusing from trash incinerators and factories into the atmosphere. Here incompressible fluid flow in the atmosphere is first calculated using the 3D finite element method. Then the diffusing process of contaminant particles with different weight is traced within the time dependent finite element solutions, and visualized.

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The behavior of the horizontal interface between two phases which are distinguished by their density is simulated by using the lattice Boltzmann method for non-ideal gas in this paper. The external force gives momentum in the horizontal direction to the low-density phase superposed on the high-density phase. It is observed that the interface is made instable and deformed by the velocity difference between two phases.

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