Boiling of R404A Refrigeration Medium Under the Conditions of Periodically Generated Disturbances

An attempt was made to evaluate the impact of external, periodically generated disturbances on the boiling process of the refrigeration medium in a flow. The experimental investigations were conducted under the conditions of periodic changes (increase and fading) of the mass flux density of the refrigeration medium for constant refrigeration chamber heat loads. This led to a change of the pressure and temperature along the path of the flow of the medium in a coil tube of the evaporator. It was confirmed that the boiling process of the refrigeration medium in a flow exhibits wave properties, which are characterized by finite values of the displacements of the disturbances. By way of dimensional analysis, nondimensional dependences were determined that specify the velocity of the displacement of the pressure change signal and the temperature change signal. The investigations were conducted with the use of an environmentally friendly R404A refrigeration medium.