An experimental investigation of a heat pipe integrated power module
A novel flat plat heat pipe (FPHP) integrated in high power module instead of metal substrate is developed. Compared with the metal subtrate, the FPHP uses two-phase boiling heat transfer to diffuse heat flux in power module.Thus the FPHP diffuses significantly the collect heat source to the more larger condensation area. Analyze the use of a FPHP as a heat spreader to spread out the heat from the die to the heat sink.The transient and steady heat transfer performance of the FPHP was experimentally measured.The experiment indicates that the FPHP of isothermal and high convection coefficient can improve the heat transfer capacity for the integrated power electronic module (IPEM), which make thermal resistance decrease 30 percent. The maximum thermal flux density of IGBT die is obtained to 186 W/cm2. IPEM based on FPHP can avoid the power uprush and raise the ability of resisting thermal impact.
Temperature Variation and Heat Transfer in Triangular Grooves with an Evaporating Film
A mathematical model for the evaporating heat transfer coefe cient and temperature variation along the axial direction of a grooved plate has been developed. The model includes the effects of the capillaryinduced e ow in the grooves caused by the surface tension, the two-dimensional heat conduction occurring in the wall and liquid e lm, and the e ow and evaporation of the thin e lm caused by the disjoining pressure and surface tension in the thin e lm region. The results obtained from this model indicate that if a constant heat e ux boundary condition is applied, the heat transfer coefe cient will decrease and the wall temperature will increase along the axial direction. In addition, the apparent contact angle increases with increasing superheat, and hence, the heat transfer rate through the micro region also increases along the axial direction. Finally, it has been demonstrated that the contribution of the surface tension variation caused by temperature increases in the micro region can be neglected. This work will lead to a better understanding of the axial heat transfer coefe cient and temperature distribution on grooved surfaces, and how these parameters affect the e lm thickness.
Image Projection in Immersive 3D Visualization Laboratory
In recent years, many centers in the world attempted to build a virtual reality laboratory. The main idea of such laboratory is to allow the user to “immerse” into and move in a computer-generated virtual world. In the paper, the underlying principles of the system of virtual reality (VR) are described. The selected implementations constructed by the research centers of the world are also presented. The cave automatic virtual environment (CAVE) installation is planned to be implemented at the Gdansk University of Technology. In this solution, the images will be projected on flat screens arranged in the form of a cube. The user will be located inside a transparent sphere freely rotating inside a cube, which allows simulation of free movement without changing the position of the screens. A walking motion of the user will trigger changes in the computer-generated images on screens surrounding the sphere thus creating an illusion of motion. The problems of visualization in the planned installation are outlined and discussed.