Measurements of Decompression Wave Speed in Natural Gas Containing 2-8% (Mole) Hydrogen by a Specialized Shock Tube
Bibliographic record
Abstract
The Battelle two-curve method is widely used throughout the industry to determine the required material toughness to arrest ductile (or tearing) pipe fracture. The method relies on accurate determination of the propagation speed of the decompression wave into the pipeline once the pipe ruptures. GASDECOM is typically used for calculating this speed, and idealizes the decompression process as isentropic and one-dimensional. While GASDECOM was initially validated against quite a range of gas compositions and initial pressure and temperature, it was not developed for mixtures containing hydrogen. Two shock tube tests were conducted to experimentally determine the decompression wave speed in lean natural gas mixtures containing hydrogen. The first test had hydrogen concentration of 2.88% (mole) while the second had hydrogen concentration of 8.28% (mole). The experimentally determined decompression wave speeds from the two tests were found to be very close to each other despite the relatively vast difference in the hydrogen concentrations for the two tests. It was also shown that the predictions of the decompression wave speed using the GERG-2008 equation of state agreed very well with that obtained from the shock tube measurements. It was concluded that there is no effects of the hydrogen concentration (between 0–10% mole) on the decompression wave speed, particularly at the lower part (towards the choked pressure) of the decompression wave speed curve.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".