The subcooled flow boiling heat transfer coefficient is a function of $\rho ,v,dh,\mu ,k,\Delta Tfw,Cp,hfg,\sigma s\u2009and\u2009q\u2033$, i.e., *h* = *f*$(\mu ,\rho ,v,dh,k,\Delta Tfw,Cp,hfg,q\u2033,\sigma s)$. The properties and parameters chosen are combined as dimensionless numbers by Buckingham's $\pi $-theorem. These dimensionless numbers are

$\pi 1=k\Delta Tfw\rho vsdh,\u2003\pi 2=Cp\u2009\Delta Tfwv2,\u2003\pi 3=\sigma s\rho v2dh,\u2003\pi 4=hfgv2,\u2003\pi 5=q\u2033\rho vs,\u2003\pi 6=hT\Delta fw\rho vs,\u2003and\u2003\pi 7=\mu \rho vdh$