"220V Cooling Fan" forced convection heat sink thermal resistance calculation Forced air cooling capacity than the natural air cooling can increase a lot. Because the air in the radiator cover is not uniform convection, so the forced air cooling thermal design is not easy to calculate. Here's the cover model by measuring the wind speed to estimate the thermal method. First make a housing model, which includes housing shape, "220V Cooling Fan" the number and position of the wind direction over the radiator, the radiator layout surrounding components and the like. When the fan is working, with the anemometer to measure air flow into and out of speed. It should be noted, "220V Cooling Fan" should be at the center of the radiator speed measurements, and then find the average velocity of air inflow outflow.