What is the coefficient of expansion of fuels and how do you calculate their volume with respect to different temperatures?

Answer

Dear Brigitte,

The coefficient of expansion of some liquids can be found on the link on the right, or you can search for the term ‘thermal expansion coefficient’. This coefficient gives the relative volume change at a certain temperature change. For gasoline, that coefficient is 0.00095 (1/°C). So if you heat gasoline from 20°C to 30°C, it will expand by 0.95%: 0.00095 x (30°C – 20°C) = 0.0095 = 0.95%. So 5 liters of petrol becomes 5.0475 liters of petrol: 0.0095 x 5 l = 0.0475 l.

This way you can calculate the volume for each temperature, relative to a chosen starting temperature. To represent this in a graph you only need two known points (because it is a straight line). An example can be found in the Excel file on the right.