Pressure loss tests with LN2 on pleated screen samples

Kurzfassung

The current focus on research of advanced cryogenic upper stage technologies is the development of Propellant Management Devices (PMD). Main elements of a PMD are metallic screens. These screens are used for multiple purposes, such as to filter the propellant and oxidizer for example. But there is another major task for such screens: they are able to detain gas bubbles in a liquid flow. This is important to provide a pure liquid flow of propellant and oxidizer to the spacecraft’s engine. Regarding to this the Bubble Point becomes important. It describes the maximum pressure difference across a screen, when gas bubbles can break through. It is of importance, that in a feed line system the pressure drop across a metallic screen device never becomes higher than the Bubble Point of the used screen. Otherwise a gas-free fluid flow cannot be provided. For that reason it is important to know the pressure loss behaviour of metallic screen elements. DLR Bremen provides in cooperation with EADS Astrium Bremen tests for screen samples of metallic screens. As test liquids liquid nitrogen and water are used. This document describes the experiment setup for LN2.