Dr. Alfonso Ortega - Mechanical Engineer
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When youíre eating something thatís too hot, like soup, what do you do to cool it down? You blow on it! When you blow on the soup you are bringing cooler air into contact with the hot surface of the soup, and the cool air carries off some of the soupís heat. What blowing on the hot soup actually does is transfer the heat from the soup to the air. The same process is being used when you turn on a fan in a hot room. It is called convection. Convection (and, more generally, heat transfer) is of great interest to me, and I study it intensely in my laboratory to understand exactly how it works.

Convection is something that is very necessary in the world we live in today. One of the most important reasons I study convection is for computers. The processor in a computer has to work harder and harder as more tasks are put upon it; therefore it gets hotter and hotter as it has more things to accomplish. However, when a computer gets too hot it does not perform efficiently. So we need to find a way to keep the computerís processor cool as it does its many tasks. This is where the studies I perform in my laboratory come in. We have been trying to cool the processor down by means of convection, where we run cool liquid past the hot processor. The heat is transferred to the cool liquid, much like when you blow on your hot soup. It is then carried away, circulated to cool down the liquid, and the whole process starts up again. However, we didnít come up with this idea ourselves. Actually, we used the human brain as an example to follow. The human brain uses about 20% of the total energy the body produces, performing many tasks at once that keep the body running smoothly and correctly (much like a computerís processor). All of that activity produces a lot of heat. So what does the body do to keep the brain from overheating? There are many blood vessels that carry blood into the brain. From there the vessels branch off, getting smaller and smaller as they come into very close contact with the brain itself. The heat from the busy brain is then transferred to the blood in these tiny blood vessels, which is then channeled out of the brain. The blood from the tiny veins flow into larger veins as they are circulated through the body, cooling down in the process. We are trying to use similar methods to cool processors, by having liquid go into smaller and smaller channels as they get closer to the processor itself. The heat is then carried away by the liquid that came into close contact with the processor. The liquid then drains into larger and larger channels as it circulates through the system, cooling as it circulates. So, by studying the way convection works in the human body (especially the brain), we have been able to apply our knowledge to many other important things in life.

I love my job as a professor at The University of Arizona. I am able to work on interesting and important engineering problems, while at the same time I get to teach others about the things that I care about most. I also feel like the work that I do is useful, such as developing cooling methods for computer processors. All of this combined makes me feel privileged to have the job that I have.

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