Design007 Magazine

64 The PCB Design Magazine • October 2015 article changed slightly before the first thermal simu- lation gets to run. Thermal simulation is critical to avoid any damage to the lighting system caused by either environmental impacts, such as solar radia- tion, or a poorly designed system. A fan that is used for cooling high-bright LEDs could create a thermal short-circuit—when the hotter air that comes out of the heatsink from the LEDs is sucked back into the fan and reused, drastically reducing the cooling efficiency. The result is an even hotter LED junction temperature and a damaged system. In the physical assembly, fix- ing this flaw is costly and time-consuming, and it's unnecessary when the error can be easily caught within the simulation before the physi- cal model is created. New CFD technologies are available that can move thermal simulation further up in the design process, automate laborious analytical tasks, and eliminate the need for geometry sim- plification. This type of CFD software, such as FloEFD ® , integrates directly with MCAD tools, which enables design engineers to match the thermal simulation with the latest design it- eration. It also provides automatic meshing, which speeds up the entire thermal simulation process. However, accuracy should not be sacri- ficed in the name of faster simulations. The cor- responding physics must be represented in the simulation with a highly accurate result com- pared to physical prototype experiments. Thermal simulation for automotive lighting designs needs to address extreme and critical operating issues; for example, a car leaves a rela- tively humid warm garage after a rainy day and goes into the cold outside the following day and an undesirable condensation film starts to build up on the front lens of the lighting sys- tem. Simulation of this situation requires cer- tain capabilities in the software such as a Monte Carlo radiation model and condensation calcu- ANALYzING CONDENSATION AND EVAPORATION IN HEADLIGHTS WITH THERMAL SIMuLATION Figure 2: CFD Mesh needed to model the headlight in thermal simulations. Figure 3: Basic parts of the headlight model.

• Cover
• Feature Articles — Accelerating the PCB Design Cycle
• Table of Contents
• Column — Squeezing Seconds Out of the Design Cycle
• Feature — Don't Be Held Hostage by Design Cycle Time
• Short — Whelen Engineering: The First New Captive in Decades?
• Feature — Accelerating the Design Cycle: Moving from Discipline-Centric to Product-Centric Design
• Short — Discovery about New Battery Overturns Decades of False Assumptions
• Feature — The Readers Speak: Tips on Accelerating Your Design Cycle
• Short — Superconductivity Trained to Promote Magnetization
• PCB007 Highlights
• Feature Column — Speeding up the Design Cycle: 10 Things to Remember
• Column — Stackup Planning, Part 4
• Short — Big Range of Behaviors for Tiny Graphene Pores
• Column — Avoiding the Black Spot of Negative Expectations
• Short — Back to the Future: Science Fiction Turns Science Fact
• Column — Impact of Final Plated Finish on PCB Loss
• Short — How Leaky is Your Device?
• MilAero007 Highlights
• Article — The Gerber Guide, Chapter 3
• Article — Analyzing Condensation and Evaporation in Headlights with Thermal Simulation
• Short — Energy Out of Thin Air
• Top Ten Recent Highlights from PCBDesign007
• Events Calendar
• Advertiser Index and Masthead