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Trailer Tires Overheating.
On Fri, 31 Oct 2003 13:55:55 GMT, "Mark Browne"
wrote: Rick and I just worked this out for water. In a race car tire that reaches 225 F to 250 F during normal operation, there *is* a phase change in water, from liquid to vapor. The newly introduced water vapor can add a significant component to the partial pressure composition of the tire. The only thing left here is to determine how much liquid water might be found inside a tire in different settings. If there's any liquid water in the race tire/wheel at all, the tire filler and wheel balancer should be fired. At the speed those tires rotate, even a small amount of liquid water (say a few grams) would be noticed as a vibration because the tire would be out of balance. It doesn't get spread evenly around the inside of the tire. Now in the temperature range of interest, operating tire temperatures, are any of the materials you mention (Nitrogen, Argon, Oxygen) undergoing any phase changes? If not, do they show any appreciable deviation from the ideal gas properties in the temperature range of interest? It's pressure as well as temperature that would cause them to deviate from ideal gas properties. And the pressures are not high enough. Typically, you have to go above around 150 psi to notice any deviation from the ideal gas laws. You have to go much higher than that for it to have any appreciable effect. As far as temperature is concerned, they deviate from ideal gas properties at very low temperatures, temps near the phase change to liquid. The higher the temp, the more ideal the gas behaves. If you're only a few degress away from the phase change, you won't notice any deviation from the ideal gas laws.. There is one other way a gas can deviate from the gas laws, and that's at very small volumes. But the container must be so small that the volume of the gas molecules themselves must be a significant portion of the container. That is not the case with a tire. If not, suck it up and move on. Mark Browne P. S. You would not be doing a Jax here, would you? That is, trying to define the problem in such a narrow way as to give yourself a little wiggle room. This is not necessarily a bad thing - some us miss toying with Jax! At first, I thought he was Jax. But Jax at least had the courtesy to confine the things he was wrong about to on-topic subjects. This idiot is all over the spectrum. Steve |
Trailer Tires Overheating.
basskisser wrote:
Yes, I agree, the level of scientific illiteracy is frightening. Here you go, and Shelikoff, can you read this and comment?? There are several properties of gasses that can easily be demonstrated using liquid nitrogen. These properties include phase changes (gas to liquid, liquid to gas, and visa versa) There isn't much new that can be added to your posts on this subject. I first thought you were just argumentative and not too bright but now I see that you are both argumentative and really stupid as well as curse with a very short attention span and an obvious learning disability. If you will reread or have someone read to you my post of October 28 at 8:56am message ID . net you may gain a glimpse of the fact that this has already been pointed out as a possibility for your inability to comprehend the subject. Here it is again just in case you can't find the original. ------------------------------ I think most of this nonsense about nitrogen in tires not expanding as much as air comes from the fact that few people really understand the properties of gases. There is a little phrase in the gas laws that refers to "phase change" ... that is where the followers of the myth may be running aground - (boating content). Liquid nitrogen will vaporize to produce a volume of gas that occupies about 700 times that of the liquid. Liquid oxygen will vaporize to produce a gas that occupies around 860 times the volume. Vaporization is the phase change. Once the liquid has evaporated the resultant gas, nitrogen, oxygen, or water vapor, will follow the gas laws and when the correct law is applied (there are several) the properties of those gases are very predictable and if you understood them you would see that the properties of those gases are identical in their behavior under the conditions which race car teams and trailer boaters operate. ------------------------------- I give up Basskisser, it has become obvious you are not really interested in learning anything but are simply looking for a fight, trolling, or just too thick to benefit from a discussion in which you are ill equipped to participate. Rick |
Trailer Tires Overheating.
"basskisser" wrote in message om... There are several properties of gasses that can easily be demonstrated using liquid nitrogen. As I clearly stated, the ideal gas laws apply as long as you are NOT operating in the temperature/pressure ranges that will result in a phase change for the elements involved. For the pressure and temperature that a tire will be exposed to the gas laws apply. Once you start talking about liquid nitrogen we are clearly in the phase change realm. You may also notice though that they will also expand a bit faster than the heavier gasses. No. They have a lower boiling point, and thus as you watch them react with the surroundings they will start boiling sooner. It takes a significant amount of engergy to make an element/compond change state. Start with a mixture of elements/componds (assuming that they don't react and form a new compond) that are all cooled below any of their boiling points (the insertion into the liquid nitrogen) and then start adding energy (remove it from the nitrogen, it absorbs energy from the surrounding air). Track the temperature of the mixture over time. You will see a fairly rapid and linear rise in temperature until it reaches a temperature where one of the elments/componds changes state. At this point the temperature will remain constant until all of the element has changed state. The temperature will increase linearly again until the next state change temperature is reached. If you are comparing the rate at which such an experiment will inflate a balloon, then a mixture that has an element/compond that changes state at a lower temperature will certainly start inflating sooner and do it more rapidly. This isn't a function of the gas, it is a function of the stage change. The differences in the expansion rate becomes even more obvious if argon is available. Argon has a very small difference between the freezing point and boiling point (4o C) thus an argon filled balloon will expand very rapidly. All elements/compounds expand as they transition into the gaseos state. This is not universally true for the transition from solid to liquid. Many elements/compounds, including water, have a "triple point", a temperature/pressure combination that will allow all three phases to exist at the same time. Predicting the exact expansion rates of a mixture where multiple state changes are involved is a bit more tedious, although the expansion between solid and liquid would be dramatically less than between liquid/solid and gas. Compare this to a breath filled balloon or a balloon filled with a gas such as ethane Stay above the boiling point of ethane and these two will behave the same. Heat both balloons the same amount and they will both expand the same amount. Now, there is one characteristic that might lead you to a false conclusion, and that is the rate at which the change occurs. If you took the two balloons from a cool room into a warm room you might see one of the balloons expand faster than the other. Leave them there until they reach equilibrium, however, and they will both expand the same. This is due to the thermal resistance. Just like aluminum heats up faster than iron. Back to what I have been saying all along: PV=nRT. It works for the temperatures and pressures that a tire will be operated at. It doesn't matter what the gas is. If the volume stays constant, and you change the T by x%, you change the pressure by x%. It is basic gas law, you should have learned this in high school chemistry class. |
Trailer Tires Overheating.
"Del Cecchi" wrote in message ...
Please explain how now nitrogen and oxygen differ? Mark Browne Nitrogen has an atomic weight of 14 and oxygen is 16? I can live on pure oxygen, but pure nitrogen will kill me? Not only that..... The nitrogen in normal "air" is responsible for a real strong "buzz" (nitrogen narcosis, rapture of the deep, ect) when scuba diving below depths of 130'. Too much oxygen at depth and you can die (Ox Tox). Got to add a little some helium (15-30%) while removing same amount of nitrogen to alleviate those little "problems" when deep diving. Has anyone pointed out to "basskisser" the "air" we breath is 79% nitrogen and 21% oxygen? -- SJM |
Trailer Tires Overheating.
Hydrogen is even better yet (better heat transfer coefficient). It is what is
used to cool the 1000 megawatt generators at power plants as air can't carry the heat from resistance in the windings away fast enough. Just watch out for flames or sparks. Also hydrogen tends to diffuse through the tire so you have to replenish it more often. JJ On Sun, 26 Oct 2003 00:00:08 GMT, "Lawrence James" wrote: They have it at race tracks. Otherwise you need a tank of it. Know anyone in the hvac business, they use it to purge refrigerant lines while they braze. Not really likely to help enouhg to be worth the trouble though. The other posters are right, bigger wheels are the right solution. "John Gaquin" wrote in message ... "Wwj2110" wrote in message nitrogen helps tires run cooler How does that work? JG James Johnson remove the "dot" from after sail in email address to reply |
Trailer Tires Overheating.
On Sun, 02 Nov 2003 00:31:47 +0000, James Johnson wrote:
Hydrogen is even better yet (better heat transfer coefficient). It is what is used to cool the 1000 megawatt generators at power plants as air can't carry the heat from resistance in the windings away fast enough. Just watch out for flames or sparks. Also hydrogen tends to diffuse through the tire so you have to replenish it more often. Having worked in a 1000 MW generating station, I can safely say this is doggie-donuts. I wouldn't have hydrogen (or any explosive gas) within 100ft of a high-power generator! Lloyd Sumpter |
Trailer Tires Overheating.
Lloyd Sumpter wrote:
Having worked in a 1000 MW generating station, I can safely say this is doggie-donuts. I wouldn't have hydrogen (or any explosive gas) within 100ft of a high-power generator! Hydrogen cooling is pretty common. He isn't, however, thinking about just where that heat in a tire is supposed to go. It's not like there is a heat exchanger to remove the heat from the gas that was heated by the rubber surrounding that gas to begin with. Rick |
Trailer Tires Overheating.
On Sun, 02 Nov 2003 19:48:12 GMT, Rick wrote:
Lloyd Sumpter wrote: Having worked in a 1000 MW generating station, I can safely say this is doggie-donuts. I wouldn't have hydrogen (or any explosive gas) within 100ft of a high-power generator! Hydrogen cooling is pretty common. He isn't, however, thinking about just where that heat in a tire is supposed to go. It's not like there is a heat exchanger to remove the heat from the gas that was heated by the rubber surrounding that gas to begin with. The wheel. I can see how the heat conductive properties of the gas can make a difference conducting heat from the tire to the wheel at different rates. Especially since the rubber itself isn't a good heat conductor. Steve |
Trailer Tires Overheating.
Steven Shelikoff wrote:
The wheel. The area of the wheel exposed to the gas is so small compared to the area of the tire producing the heat that I doubt it has much of any practical value in dissipation of heat above and beyond air flow over and radiation from the tire itself. Though it doesn't apply much to boat trailer tires, the heat conductivity of the gas would work against tire cooling in the case of race cars and aircraft since it would serve to increase the rate of tire heating in heavy brake application. Many aircraft tire failures are due to overheated brakes, heating the wheels to the point of causing the tires to blow out or burn, not from heat generated by the tires themselves. Rick |
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