One of the major technical problems associated with cryogenic liquid propellant systems used to supply rocket engines and their subassemblies and components is the phenomenon of propellant tank pressurant and ullage gas collapse. This collapse is mainly caused by heat transfer from ullage gas to tank walls and interfacing propellant, which are both at temperatures well below those of this gas. Mass transfer between ullage gas and cryogenic propellant can also occur and have minor to significant secondary effects that can increase or decrease ullage gas collapse. Pressurant gas is supplied into cryogenic propellant tanks in order to initially pressurize these tanks and then maintain required pressures as propellant is expelled from these tanks. The net effect of pressurant and ullage gas collapse is increased total mass and mass flow rate requirements of pressurant gases. For flight vehicles this leads to significant and undesirable weight penalties. For rocket engine component and subassembly ground test facilities this results in significantly increased facility hardware, construction, and operational costs. "Collapse Factor" is a parameter used to quantify the pressurant and ullage gas collapse. Accurate prediction of collapse factors, through analytical methods and modeling tools, and collection and evaluation of collapse factor data has evolved over the years since the start of space exploration programs in the 1950's. Through the years, numerous documents have been published to preserve results of studies associated with the collapse factor phenomenon. This paper presents a summary and selected details of prior literature that document the aforementioned studies. Additionally other literature that present studies and results of heat and mass transfer processes, related to or providing important insights or analytical methods for the studies of collapse factor, are presented.
An independent analysis using theoretical calculations with nominal test chamber configuration geometries was performed to evaluate the effects of small and large variations in test apparatus chamber configurations, test chamber test pressures [446KPa to 69.07 MPa], and in preset initial striker pin positions [striker pin transmits mechanical impact energy from the test apparatus drop plummet to material test samples within the test chamber]. The effects evaluated were the total energy losses between the drop plummet energy impartation to striker pin and the striker pin energy impartation to the test sample of different given test apparatuses. These total energy loss effects directly determine whether or not a sufficient percentage of the drop plummet energy is in fact transmitted to the test sample during mechanical impact tests.
During the advanced and final development phases of rocket engine component and subsystem testing failures are very likely to occur from time to time. To minimize or prevent damage or destruction to the components and to the test facility itself, high pressure oxygen supplied must be cut off rapidly on the order of 100 to 400 milliseconds. However, rapid cutoff of liquid oxygen, as well as, other liquids and high pressure gases can impart large pressure surges and hammer forces. For liquid and gaseous oxygen this phenomenon can initiate ignition and subsequent destruction of test articles as well as facility piping systems. An additional concern is the use of liquid oxygen pressure and flow control valves required to operate these type of facilities. Pressure differentials across valves and induced turbulence and flow separation must be understood and analyzed during facility design.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.