Digital Moiré Subtraction Interferometry (DMS) for Electronics Cooling Applications in Enclosures

Optical non-invasive temperature measurement techniques such as interferometry are particularly advantageous in obtaining temperature information non-invasively from enclosed low velocity flows induced by thermal sources, as commonly arise in electronic systems. The single greatest restriction in the application of interferometry as a standard measurement methodology has been the enormous cost associated with the optical equipment required. This cost is due to the quality of the optics required, which exhibits an exponential dependence on size. Digital Moiré Subtraction is a technique which removes the restriction on the use of high quality optics, thereby enabling reasonably large fields of view. In this paper, a Digital Moiré Subtraction interferometer configuration is presented with a 140mm field of view. First, the ability of the interferometer to accurately measure the free convection temperature field about an isothermal horizontal cylinder is examined through a comparison with measurements from the literature using classical interferometry. The technique is then applied to the thermal interaction between 2D components representing BGAs mounted on a vertical PCB. Qualitative and quantitative evaluation of the interferograms show the significant David Newport EP-06-1022 Page 2 of 42 influence of in-plane PCB conductivity on the temperature field about the PCB. The spacing to length ratio above which upstream components on a PCB experience enhanced cooling is reduced from 4 to 3 for a PCB with a high effective in-plane conductivity (15 W/mK).

NEWPORT David;  WHELAN Maurice;  FORNO Colin; 

2010-10-01

ASME-AMER SOC MECHANICAL ENG

JRC60259

1043-7398,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC60259,