Pressure surge attenuation using engineered flow elements during adiabatic compression testing of oxygen (SAFETY)

Oxygen gas is extensively used in a wide range of medical procedures. Usually stored up to 300 bar in cylinders, gas control equipment (valves and regulators) are used to handle the flow of oxygen. Such equipment has to qualify stringent testing conditions formulated by organizations such as ISO (ISO 10297) or ASTM (ASTM G175) to be approved for service. Despite passing such tests, ignition incidents involving such equipment have been reported during service highlighting the inherent risks involved in using pressurized medical oxygen (> 99.5 % purity). While adiabatic compression and particle impact are the predominant causes attributed to ignition, there exists a lack of empirical or numerical database describing the underlying flow phenomena (e.g., shock propagation and reflection, supersonic flow, rapid pressure-temperature surge) during testing which could aid engineers in improving product design and safety. Rotarex is a world leader in the design, manufacture, and supply of premium quality medical oxygen equipment (OE). The company, in collaboration with the University of Luxembourg (UL), has established a state-of-the-art oxygen pressure surge test (OPST) facility dedicated to researching the aforementioned gas flow dynamics in its products based on the ISO 10297 standard. As the medical industry migrates toward oxygen storage up to 450 bar the inherent risk of ignition rises drastically and Rotarex is committed to incorporate testing and simulation based knowledge to their existing know-how to design products ensuring the highest level of safety. The proposed project investigates the effect of engineered flow elements with predefined flow path in attenuating gas dynamic pressure and temperature surge near ignition prone OE parts (e.g. non-metallic seat of pressure regulator) during ISO 10297 testing. Up to 4 flow element designs are planned to be tested at the OPST facility to systematically study flow parameters (pressure drop, flow velocity, pressure and temperature field) in the vicinity of both the flow element and the OEtest piece. Concurrently, computational fluid dynamic (CFD) simulations to study ISO 10297 testing will be performed using FLUENT solver at UL’s supercomputing cluster to acquire local and global flow-field information and be compared with test data to validate the CFD model. Another part of the project deals with 2D-CFD modeling of ignition caused by particle contaminants. As contaminants are unavoidable during the operational life cycle of any gas equipment Rotarex is interested in understanding the flow dynamics of particle-laden gas flow with and without flow elements and its interaction with critical OE parts leading to ignition. This proposal thus aims to research a challenging problem through (i) application of novel flow element materials employing systematic testing-CFD approach and (ii) initiation of CFD-oriented efforts with the aim of building a reliable model capable of predicting particle impact ignition and its propagation to help engineers come up with viable solutions tackling these issues that benefit the entire medical gas control equipment industry. Being the first of its kind research in this field, a successful outcome contributes to Luxembourg’s industrial competitiveness while aiding Rotarex to sustain its position as a world leader in supplying premium quality gas control equipment.