If you have a small fan that blows hot air, and a larger fan that blows cold air against it, what happens to the hot air?

Question

For context, I have a laptop that has a fan that sucks in cold air from the top on the left side (for cooling the cpu), and a fan that blows hot air out the bottom on the right side (for cooling the gpu). It has problems with heat, so I put a large cooling fan underneath it that sucks in hot air from the bottom and pushes it onto the bottom of the laptop. I'm curious to know if this actually does anything at all.

I apologize if this is a dumb question, as I have a computer programming background and not a physics/engineering background. I simply couldn't find an acceptable answer on google.

Answer 1

What would happen (if anything) is making it harder for the hot air to get out of the bottom. What you need to do is increase the air flow through the machine.

The first thing to do (assuming the machine is designed correctly; I have had one that wasn't) is to make sure that inside dust isn't restricting airflow. Take it apart and blow it out. Note - do not just blow air into the fan ports without holding the blades still, you can over-speed the fan and break it.

If that doesn't work, consider reversing your fan on the bottom and pulling the hot air out. If that isn't enough, them apply foam to the add-on fan to make a good seal - that will pull more air through the machine.