Heat Sink Fin Orientation

Thermal resistance will probably increase since it will difficult airflow i e.

Heat sink fin orientation. Wesley lee nov 1 16 at 12 54. And the radiation is omnidirectional. Orientation effects on natural convection heat dissipation of rectangular fin heat sinks mounted on leds 1. The first plot traveling from the lower left to the upper right is the natural convection curve of heat sink temperature rise tsa versus q.

The effect of orientation of this heat sink relative to gravity field will be offset by the fact that about 1 3 of heat flux will be emitted in the form of radiation if the sink is anodized or painted black which will make the surface emissivity to above 0 9. Typically the fins are oriented in a way to permit a natural convection air draft to flow upward through rectangular u channels or ducts formed by the fins. You haven t mentioned if you have forced air flow i e. Respectively bonded fin heat sinks and skived fin heat sinks suit these requirements nicely.

Experimental setup and analysis method. The heat sink should be oriented as in fig 1 or fig 2 under natural convection cooling. Unique fin requirements thermal engineers sometimes need heat sinks with either very tall fins or very thin fins that are tightly spaced. A trapezoidal fins heat sink with various orientations tested under a controlled environment.

Test results indicate that the sideward horizontal fin orientation yield the lowest heat transfer coefficient. In which case the orientation of the fins will probably make less of a difference. The experimental setup is. Heat sinks are devices that are used to enhance heat dissipation from hot surfaces to cooler ambient air.

An advantage of bonded fin designs is that the heat sink base and the fins can be of different metals. However the sideward vertical fin orientation gave the best performance on the natural cooling. It is recommended that the heat sink be installed to orient the fins in a direction that will not block air movement under natural convection. It is assumed that the device to be cooled is properly mounted and the heat sink is in its normally used mounting orientation with respect to the direction of air flow.