Screen channel liquid acquisition device bubble point tests in liquid nitrogen

Abstract

The primary parameter for gauging performance of a liquid acquisition device (LAD) is the bubble point pressure, or differential pressure across a screen pore that overcomes the surface tension of the liquid at that pore. Recently, cryogenic bubble point tests were conducted in liquid nitrogen across a parametric trade space to examine the influential factors that govern LAD performance, and 1873 data points were collected. Three fine mesh screen samples (325×2300, 450×2750, 510×3600) were tested over a wide range of liquid temperatures (67–114K) and pressures (0.032–1.83MPa), using both autogenous (gaseous nitrogen) and non-condensable (gaseous helium) pressurization schemes. Experimental results in liquid nitrogen are compared to recently reported results in liquid hydrogen, oxygen, and methane. Results indicate a significant gain in performance is achievable over the baseline 325×2300 reference bubble point by using a finer mesh, operating at a colder liquid temperature, and pressurizing and subcooling the liquid with the noncondensable pressurant. Results also show that the cryogenic bubble point is heavily affected by enhanced heating and cooling at the screen liquid/vapor interface by evaporation and condensation.