CFD Case Study

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Phoseon Thermal Analysis

Phoseon is an innovative leader in the field of LED light bars that can generate intense UV light for a variety of industrial applications.  These LED light bars present a unique thermal challenges due to their high power and compact environments.  In their more recent design, Predictive Engineering was contacted to execute a CFD analysis on an extremely tight timeline.  With the direct CAD import capabilities of CFdesign and its fast solver capabilities all project goals were met to pack a heck lot more heat into a far smaller package.

And for those readers that would like the straight scoop on Phoseon's technology:

"Phoseon’s proprietary Semiconductor Light Matrix (SLM) technology is a breakthrough in high power light applications. It uses a tightly-integrated array of high-intensity light-emitting semiconductor devices. Ultraviolet SLM arrays produce significantly higher intensity light than UV LEDs or other diode-based light sources. UV SLM sources provide purer light with less wasted energy and longer useful life than ultra violet lamp-based sources.

SLM technology combines patent-pending, high technology micro optics and micro-cooling in a cost-effective MOEMS (micro opto electro-mechanical system) package. The result is a high intensity light system that offers an efficient, scalable, safe, long-life, and environmentally friendly alternative to traditional sources. Phoseon’s family of SLM-based UV devices can be operated as portable, stand alone systems for exposure and curing, or can be easily integrated into other pieces of equipment. The compact size of the light source and associated power supply, as well as simple electronic control, allow instant on/off, making integration a snap.

SLM is a solid-state electronics technology that does not use mercury or does not produce ozone making it a safer, more environmentally attractive alternative to traditional lamp technologies."

Modeling Assumptions and Details: The CFD model was constructed based on 3-D geometry provided by Phoseon. This geometry was slightly simplified for improved numerical performance.

All flow was driven by a 40x40x28 Sunon fan that could deliver 24 CFM at 0.0 inch H20 backpressure. The fan curve was directly integrated into the CFD model. The flow through the light box was restricted by an exit baffle with 25% of its cross-sectional area blocked (75% open). This flow restriction increased the internal pressure within the box and preferentially drove a portion of the the air stream through the exit passages drilled into the box alongside the high power LED arrays.

Aluminum was used for all heat sinks.  The heat generating chips were modeled as ceramic. A thermal interface compound was used between the high power LED arrays and its massive aluminum heat sink. The trade name for this thermal compound is Silverstrate.

The thermal load case consisted of the high-power LED arrays, FETs and the circuit board.

All modeling work was done with CFdesign V8.0. This software is manufactured by Blue Ridge Numerics of Charlottesville, VA and is sold and supported in the Northwest by Predictive Engineering, Inc.

Summary: Results were delivered on time and validated the design intent with only a few design iterations.