Termodinámica de cohetes de agua (inglés)

We study the thermodynamics of a water rocket in the thrust phase, taking into account the

expansion of the air with water vapor, vapor condensation, and the corresponding latent heat. We

set up a simple experimental device with a stationary bottle and verify that the gas expansion

in the bottle is well approximated by a polytropic process PVb¼constant, where the parameter

b depends on the initial conditions. We find an analytical expression for b that depends only

on the thermodynamic initial conditions and is in good agreement with the experimental results.