Experimental setup and pre-experiment issues for multi-component hydrogen isotopes permeation through metals, in non-steady-state

Bidica, Nicolae; Popescu, Gheorghe H.; Monea, Bogdan Florian; Moraru, Carmen

doi:10.1016/j.fusengdes.2020.111677

Cited by 4 publications

(1 citation statement)

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“…Such particular case is when the injection of very low flows of hydrogen and/or deuterium directly into the permeation cell is the option for calibration of the measurements of hydrogen isotopes permeation fluxes, in permeation experiments performed in very different modes. (Bidica et al, 2020) An important aspect in this case is that, depending on how the experiment is conducted, very different conditions may occur in the permeation cell, as for example high vacuum -in the case of permeation to vacuum, or a wide range of pressures -in the case of permeation to another gas. Thus, the simplest way of using a single leak (of calibrated conductance) is not appropriate; besides the disadvantage due to change of the flow regimes as the inlet pressure is increased (which leads to pressure dependent conductance), also wide ranges of pressure (instead of high vacuum) at the outlet of the leak would make the task even more difficult.…”

Section: Introductionmentioning

confidence: 99%

A New Method to Generate Very Low Gas Flows for Calibration of Hydrogen Permeation Measurement. Part 1: Concept and Feasibility Testing

Bidica

Ghimis

2022

Smart Energ Sustain Env

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Generating of very low (and well-known) gas flows meets a wide variety of needs in industry and research (especially in vacuum science and technology), but also among consumers and society (e.g: calibrations of vacuum gauges and leak detectors, leak testing to verify the tightness of many industrial products, assurance of product reliability and performance, environmental and other safety issues, and so on). So far, many methods and devices have been developed for generating very- and ultra-low flows, generally with the goal of setting flow standards for metrology. However, most of them are very complex, so that in case of certain particular research applications, new or adapted methods and devices appear to be more suitable. Such particular case is the calibration of the measurements of hydrogen isotopes permeation fluxes, when very low flows of hydrogen and/or deuterium are injected directly into the permeation cell which is operated in very different modes. This paper presents the concept of a new method proposed to accomplish this purpose, its corresponding mathematical model of flow, as well as the experiments performed to test the feasibility of the method. Briefly, the concept is based on two leaks of constant conductance through which a so-called reference flow is generated, with two stages of pressure reduction, as well as on a variable leak valve through which well-controlled flows (and over a wide range) are generated to be injected into the permeation cell.

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Section: Introductionmentioning

confidence: 99%