Experimental and theoretical study of single bubble formation at the nozzle in a liquid oxygen crossflow

Abstract

In this paper, the condensation bubbles generated by the mixing and condensation of gaseous and liquid oxygen crossflow experimentally and theoretically. The mixing and condensation experiment of the bubbles was carried out, employing gaseous and liquid oxygen as working fluids in vertical tubes. Three successive flow patterns were observed: initial gas plume, condensation oscillation, and separation condensation. The corresponding characteristics include gas mass aggregation, bubble surface smoothness and wrinkling alternately, and bubble disappearance after separation and condensation. Then, a Nusselt number (Nu) heat transfer correlation formula is fitted with a corresponding fitting error in the range of −31% ∼ 35%. In addition, bubble force balance and conservation equations were employed to establish a mixing condensation bubble model suitable for gaseous and liquid oxygen in vertical tubes, and the error between theoretical and experimental results was in the range of −25% ∼ 20%. Furthermore, the effects of working conditions and forces on bubble condensation length has been analyzed. The results showed that increasing the liquid oxygen flow rate, reducing the gas oxygen volume flow rate, or appropriately reducing the gas inlet diameter led to reducing the bubble condensation length. It was shown that the bubble drag and shear lift forces affect the condensation length mostly.