Roughness Measurements of Microchannel Surfaces
EMSL Project ID
1697
Abstract
Surface roughness may influence the heat transfer coefficients in microchannel heat exchangers, particularly in cases of boiling. Roughness may also influence flow regimes in two-phase flow. We have built a microchannel heat exchanger with upper and lower channel surfaces that are wide parallel plates. We need to characterize the roughness of these surfaces so that we can understand the nucleation, growth, detachment and combination of bubbles on them. We would remove the channel surfaces from the exchanger so that they could be examined under a two dimensional profilometer. The surfaces are polyimide and polycarbonate plastic, with platinum and gold coatings. They are flat, and are 1-3 mm thick. The roughness features to be examined are between 0.1 and 20 microns in size. All measurements will be performed in air at room temperature. The coating system used on the surfaces is a new design. The proposed experiments would also examine the coatings for changes caused by heating. EMSL staff would be needed for training our graduate student in use of the instrument, assistance in performing the measurements (at several locations on each surface), help in generating statistics on features sizes and spacings, and for supplying images of the surfaces for presentation.
Project Details
Project type
Exploratory Research
Start Date
1999-09-29
End Date
2000-06-30
Status
Closed
Released Data Link
Team
Principal Investigator