Atsushi Morihara

High-performance line contact cooling module for multichip packaging

The authors investigated the performance of a cooling apparatus which is capable of cooling semiconductor chips when brought into surface contact with the semiconductor chips, even if they are displaced vertically or horizontally at any angle. Using the proposed technique, highly efficient cooling can be achieved. The thermal resistance of the line contact cooling module was measured experimentally, and simulated by the finite difference method. The simulation result fits the experimental data fairly well.<<ETX>>

Effect of radius of cylinder on thermal resistance of line contact cooling block for semiconductor

Conduction cooling using a line contact cooling block made of highly heat-conducting ceramics is discussed. The line contact is created by a flat surface block in contact with a cylindrical surface, the gap on either side being filled by grease. Measurements show that the thermal resistance increases as the radius of the cylinder increases. This is especially marked when the dimensionless radius r/S<100 (r is the radius of the cylinder and S is the width of the contact). The total thermal resistance consists of two parts. One is the contribution of the gap between the flat surface and the geometric surface parallel to it and tangent to the cylindrical surface; the other is due to the remainder of the space between the flat and cylindrical surfaces. When r/S>>100, the thermal resistance approaches that of a grease-filled gap of 10- mu m width between two flat surfaces. The influence of surface roughness is negligible for Ra<0.5 mu m.<<ETX>>

Characteristics of air-blown gasification in an entrained-bed coal gasifier.

The characteristics of air-blown coal gasification has been studied in a process development unit of an entrained-bed gasifier. Taiheiyo and Ermelo coals were used in this work. Comparing the experimental results obtained in the two-stage gasification method, it was confirmed that there is an appropriateair distribution ratio in the two-stage method which results in the reduction of the difference in the carbon conversions of Taiheiyo and Ermelo coals. Carbon conversion shows a linear relationship with the ratio of total supplied oxygen to the carbon contents in the coals.The ratio of the experimental value, ηg (cold gas efficiency), to the theoretical value, η*g was introduced as a performance index of the gasifier. On the basis of a slag flow temperature comparison, it was concluded that only a small difference existed in the performance indexes of the air-blown and the oxygen-blown gasifications in this gasifier.