| Description |
An experimental study was performed to explore the possibility of constructing a spiral microchannel heat sink using a laser-based xurographic technology with double-sided adhesive Kapton® tape, which has a low thermal conductivity. Xurography is a rapid prototyping micromanufacturing technology that, in contrast to expensive and time-consuming traditional microfabrication technologies, enables the fabrication of inexpensive microfluidics devices in a short time frame. A set of three xurographic spiral microchannel heat sinks with different channel length, width, hydraulic diameter, aspect ratio, and number of spirals were fabricated, tested and analyzed. For all test sections, channel depth was determined by the Kapton® tape film thickness, which is approximately 105µm. The heat sinks were experimentally tested at different flow rates and heat fluxes. Four sets of tests were performed on each heat sink. Distilled water, used as the working fluid, entered the test sections at room temperature (~22°C). The supplied heat ranged from 25 to 200 W, and the Reynolds number ranged from 200 to 1800. Results showed that the device with the widest channel (3 mm) extracts more heat than those with smaller widths and requires the least amount of driving pressure. The maximum heat dissipation rate for the devices was approximately 140 W, corresponding to a heat flux of approximately 10 W/cm². The maximum convection coefficient was on the order of 6500 W/m²/K and was achieved in the widest channel device with a corresponding Nusselt number of up to 2.2. Results indicate a thermal performance that is less than desirable. Performance was adversely affected by the low thermal conductivity Kapton® tape and no enhancement due to secondary flows in the spiral geometry was observed. Comparison with a well-known macroscale curved duct correlation revealed a significant difference between the experimental results and predications. |
