In last issue's column, we discussed heat loss by convection and radiation from a printed circuit board in which heat spreads in a 2-D pattern. Here, we look at a slightly simpler situation, namely that of heat transfer by a fin into the ambient air. The situation is illustrated in Figure 1, where, for simplicity, the heat is shown flowing only out of the top surface of the … [Read more...]
Beyond the arrow plot – New methods for flow visualization
Within the realm of CFD-based flow analysis, the presentation of data is a vital issue. Researchers and developers need to gain insight, and non-technical managers and commercial staff have a critical need to understand the true ramifications of the data. Unfortunately, current methods for visualizing flow have limitations that make it difficult to interpret vast quantities of … [Read more...]
Acoustic noise emission and communication systems in the next century
Acoustic noise emission is one of several physical design issues addressed during the design of telecommunications and information technology equipment. In most systems, noise is a by-product of the air-movers used for system cooling. The amount of heat dissipated in electronic systems cooled by forced convection is directly proportional to volumetric flow rate. The flow rate, … [Read more...]
Thermal testing and control by means of built-in temperature sensors
Introduction This paper will discuss a new approach to the measurement of the thermal properties of PCBs and the packages mounted to them. It is intended to replace traditional solutions, such as using thermocouples and data acquisition equipment. The basic idea of this approach is that the IC chips themselves will be used to measure and acquire temperature data. It will be … [Read more...]
The thermal conductivity of gases
The value of thermal conductivity for most gases and vapors range between 0.01 and 0.03 W/mK at room temperature. Notable exceptions are Helium (0.15) and Hydrogen (0.18). The most common theoretical explanation of heat conduction in gases is provided by the kinetic gas theory, which treats the collisions between the atoms or molecules as the prime mode of transfer of energy. … [Read more...]
- « Previous Page
- 1
- …
- 466
- 467
- 468
- 469
- 470
- …
- 481
- Next Page »
