Flow Instabilities in Boiling Channels : Part 1 Pressure Drop Oscillation

The pressure drop oscillation in a boiling channel system was analyzed by using a lumped parameter model in which the pressure drop characteristics was described by a third order equation of the flow rate. The momentum equation in the boiling channel system was thus reduced to a Van der Pol equation. The limit cycle and the period of the pressure drop oscillation obtained from the Van der Pol equation agreed qualitatively with experimental results

Flow Instabilities in Boiling Channels : Part 2 Geysering

An experimental study on geysering was carried out in an R-113 forced flow boiling system. The effects of flow rate, heat flux density, system pressure and heating condition on the threshold of geysering and on the period and amplitude of the differential pressure at the test section were studied. The mechanism of geysering was analyzed by using a simple model. The analytically predicted period and amplitude of oscillation agreed qualitatively with the experimental results and thus supported the validity of the model