The Effect of Obstacles on a Liquid Film Available to Purchase

It has been observed in simulated nuclear reactor critical heat flux (CHF) experiments that CHF tends to occur upstream of flow obstructions, such as grid type spacers. An experimental program was conducted to quantify the effect of various obstacles on a liquid film. Although this was an adiabatic (air-water) study, a phenomenological mechanism causing dryout was observed. A simplified analysis of the observed phenomena has indicated that, above a critical Weber number, the ratio of the momenta of the liquid and vapor streams is the important parameter in determining when an upstream dry patch will form.