Phonons are lattice vibrations. The distance between two consecutive phonons is of the order of 1/N where N is the number of atoms in the lattice. At room temperature a phonon travels approx 10 to 100 lattice constants before scattering.

In this article https://www.nature.com/articles/srep17131 they say that a phonon travels $< 1 \mu m$ before scattering, that is approx 100 lattice constants (the lattice constant is approx 1 nm)

Phonons are lattice vibrations. The distance between two consecutive phonons is of the order of $1/N$ where $N$ is the number of atoms in the lattice. At room temperature a phonon travels approx 10 to 100 lattice constants before scattering.

In this article they say that a phonon travels $< 1 \mu m$ before scattering, that is approx 100 lattice constants (the lattice constant is approx 1 nm)