How to calculate the deformation amount of the inner diameter of a coiled tube due to thermal expansion
Thread Content
The stainless steel coil has a length of 800, an outer diameter of 500, and a wall thickness of 10. When it is heated from 20°C at room temperature to 250°C, by how much does the inner diameter increase? This post was last edited by wdwfwdwf on 2008-2-25 13:45]
Hot-state diameter = Thermal expansion coefficient of the material at 250°C × Temperature difference × Cold-state diameter
The formula upstairs is incorrect, right? The diameter difference should be equal to the coefficient of expansion * temperature difference * original diameter. This calculation method is based on the linear expansion formula, and it seems to result in significant errors; I’m not aware of any other methods. I hope experts can provide some guidance.
:Lol, where did my friend find something from 14 years ago? The original author has lost their mental capacity; I’ll reply using the original username here: 1. The formula mentioned above is based on the assumption that metals are isotropic, meaning their expansion coefficients are roughly the same in all directions. 2. If a coiled tube is unrolled to form a flat sheet and calculations are done using the aforementioned formula, and then the sheet is rolled back into a tube, then multiplication and division by 3.14 must be performed during the calculations. 3. The resulting difference is due to the wall thickness of the coil; since this thickness is very small compared to the diameter of 500, it was ignored in the calculations. 4. If one needs accurate data, it is best to find out the expansion coefficients of the metal in various directions, and it is recommended to conduct measurements under constant temperature conditions in order to reduce errors.