Abstract
Experiments were carried out to observe boiling behaviors of water on a vertical surface at pressures from 0.35MPa to 5MPa. The growth curves of the primary bubbles are well described by the t^<1/2> variation over the whole range of pressures. The growth rates of primary bubbles are proportional to the square root of the Jakob number, and agree with the correlation by Labuntsov with the arbitrary constant β=3. The nucleation site densities measured up to 5MPa increased in proportion to about the 1.5th power of the pressure under equivalent heat flux conditions. The dependence of the nucleation site densities on the heat flux is very similar to the results obtained near atmospheric pressure where the nucleation site density is proportional to the 1.5th power of the heat flux
