Do you like soup? I like soup. Especially on cold days in the winter. Living down south apparently ruined me for cold weather, because, even though I’ve been here in Ohio for 25 years, I still get a chronic chill in early November that won’t let go until about April. March, if I’m lucky. A nice, hot bowl of soup gives me a temporary respite from that dreaded chill, though, so yeah…I like soup.
Sometimes (OK; most of the time) I like it so much I don’t want to wait for it to cool (just slightly) to a temperature that won’t scald my tongue, so I resort to the age-old practice of blowing on those first few spoonfuls. Even though my breath is a fairly consistent 98.6F (give or take,) it’s still quite effective at transferring enough heat out for pain-free consumption. There are two reasons I’m thinking about this right now:
First reason: I’ve been working with an engineer at a large automotive plant…they were cooling a production run of metal cast parts with a series of fans. It ran pretty slowly, and they had a line of those pedestal mounted fans “waving at the parts as they went by.” The thought was, they could direct a stream of cooling air by using the focused flow of an Air Amplifier, and this might just allow them to speed up the line. And they were right. They tried a few Model 6041 1-1/4″ Aluminum Adjustable Air Amplifiers, with very favorable results. So favorable, in fact, that they ordered (40) more to outfit other casting lines in the plant, in arrangements similar to this:
Just like it might take more than one “blow” to cool off a spoonful of soup, they have installed multiple Air Amplifiers, in succession, on the lines, depending on the size, shape, and mass of the part. And the precise adjustability of the Adjustable Air Amplifiers allows them to dial in the optimum air flow, while minimizing their compressed air consumption. So the Production and Facilities folks are all very happy.
And (because I know you’re wondering) the second reason I’m thinking about conductive/convective heat transfer via air movement:
I came up with this title for this week’s blog the other day, and I can’t think of something to compare an analogy to, in the context I wish to discuss today. Isn’t that ironic?
I’ve always had good luck with analogies…if I need to explain something to someone, being able to draw a comparison to a well-known or easy to picture scenario just comes easy to me. Someone smarter than me once said “if you can’t explain it simply, then you don’t understand it well enough,” and analogies have always served me well in that regard.
They are, in fact, a popular tool of the trade in EXAIR’s Application Engineering department. The most common example is, in fact, the topic of my blog today.
If a caller wants to use a Vortex Tube to cool something that’s very hot, we may recommend a Super Air Nozzle, Air Amplifier, or Air Knife instead. The long answer is that there are two variables to consider in a conductive/convective heat transfer application using fluid flow: flow rate, and temperature differential between the object and the medium (air in this case.) If the item is indeed very hot, then you already have a very high differential between the item’s surface temperature and the temperature of the air (ambient) that you’ll be blowing on it…and our Intelligent Compressed Air Products serve to increase the air flow rate, by entraining “free” air from the surrounding environment. If there’s a moment of silence when we get to that part of the explanation, we’ll compare it to when you blow a quick breath on a spoonful of very hot soup, which, although your breath isn’t cold at all, it still cools that soup down in a hurry. In comparison to the temperature of the very hot soup your breath is cold. Then we take their order, ship their Super Air Nozzle (or Air Amplifier or Air Knife) and everyone’s happy.
If you’d like to discuss a compressed air product application – or if you can help me solve the problem of this blog’s title with a rapt analogy – please let me know. Either way, I’ll be as happy as a kid in a candy store to hear from you.