Heat expansion of tubes/rings
Heat expansion of tubes/rings
(OP)
Can anyone tell what the equation/s would be to find out how much the outside and inside diameter of a tube or ring expands?? I just had a bearing fall out of my housing cause heat expanded the housing faster than the bearing.
Thanks...Ruso
Thanks...Ruso





RE: Heat expansion of tubes/rings
The formula for expansion is:-
x=dia * coeff of linear expansion * temperature change
coeff of linear expansion for the material of the bearing housing should be found in the relevant material spec.
Temp change is just the ambient taken off the temp the bearing housing reaches.
hope this helps
regards desertfox
RE: Heat expansion of tubes/rings
The volumetric expansion coefficient [dV/V)/dT] is generally taken as 3 times the linear coefficient [(dL/L)/dT]. So, if a 75L steel tank full of gasoline at the same temperature, are both heated by 20 K (36oF), gasoline would spill out.
The linear coefficient of thermal expansion for steel: 12x10-6/K
The volumetric expansion for gasoline: 95x10-5/K
Excess volume of gasoline after heating:
(75)(20)(95x10-5 - 3x12x10-6)= 1.37L = 0.36 gallons
Therefore, it is recommended never to fill a car gas tank to the very top.
RE: Heat expansion of tubes/rings
RE: Heat expansion of tubes/rings
Thanks for your comment, the question as written is purely
a linear dimension problem relating to the diameters of the
bearing and housing.
regards
desertfox
RE: Heat expansion of tubes/rings
RE: Heat expansion of tubes/rings
If the device involves a steel bearing in a steel housing, and the differential expansion is transient, i.e during warm up, then you will need to look at the source of heat and determine relative rate of heat transfer and consequent expansion rates.
Alternatively, if the two metals are dissimilar and the problem is constant, you can determine the relative expansion empirically by considering the housing hole area and the bearing overall area and multiplying each by twice the linear expnsion coeficient for the respective materials.