By BizLED Bureau
Jan 11, 2016: With increase in demand for LED lighting in the automotive industry, the competition among the OEMs has reached a peak. All major car brand manufacturers are vying with each other to come up with innovative car lighting systems; they are offering more and more to the consumers. For example, Audi TT offers three options of headlight systems?matrix LED, full LED and Xenon.
This competition, however, is posing several challenges to the designer engineers of car lighting systems, as ensuring variety, reliability and performance of lighting systems in automobiles is getting more complex, particularly the thermal management aspect of the design.
Unlike incandescent lighting system that gives out heat through infrared radiation, LEDs give out heat through heat sinks attached to them. As a result, thermal management is an important design aspect to maintain low juncture temperatures of the LED system, which in turn, is important for safety and long life of the system.
After the external design is completed, optics like reflectors and lenses need to be incorporated in the headlight design and the functionality need to be simulated. Design engineers usually simulate individual components like the LED, heat sink and the fan to check the temperatures, but once these components are placed inside the housing, the airflow gets limited and starts affecting the lenses and reflectors.
Importance of thermal stimulation
Here the importance of thermal simulation comes in while designing lighting systems for cars because it can protect the system or the light source from any damage by environmental conditions. Even in a rough design model, thermal simulation helps to evaluate the temperatures.
But when a design engineer is working on the thermal simulation aspect, he/she needs to take care of a few design aspects. For example, the thermal management of the lighting needs proper attention. The design should be such that the lighting system can bear any type of environmental conditions like extreme cold and extreme hot climates. For example, extreme hot weather can burn holes into the lighting system. Sometimes, due to change of weather?from humid to cold?a condensation film can develop on the lens of the lighting system. Such issues need to be taken care of at the design stage. It is to be noted that a bad lighting system can not only damage the car but also lead to serious accidents like fire.
CFD can make task easy
A headlight consists of many small and complicated components like sheet of metal or plastic, reflector, ribs, pins, clips, etc. This makes the meshing process difficult, which is usually done manually. Today, design engineers are handling these complex issues with the help of computational fluid dynamics (CFD) tool, which makes meshing these geometries very easy and automatic, saving time and money.
Today?s CFD tools are sophisticated enough to help design engineers understand easily the thermal management and fluid flow in the lighting systems, and also enable them to meet the levels of reliability of the system under different weather or other environment conditions.
The advanced CFD tools incorporate native CAD geometry which creates highly accurate mesh automatically. In short, by creating automatic meshing, CFD can significantly reduce the manual work, keep the design engineers up-to-date with the simulation of the design challenges, and also reduce time and cost. CFD helps the design engineers to create an optimised computing mesh.
UL uses CFD tools to create new tests
UL is also using thermal modeling to understand the safety features of LED lighting systems, and accordingly validate test methods. It is using CFD software to create new tests and modify the existing ones. With the help of CFD tools, UL studies different LED testing configurations to understand the impact of various parameters on airflow and temperature patterns within an LED lighting system. Such tools help UL to determine the thermal performance of an LED. UL claims that its CFD models can successfully predict the temperature limits of an LED light engine.
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