Influence of Rotation Speed and Air Pressure on the Down the Hole Drilling Velocity for Borehole Heat Exchanger Installation
Bibliographic record
Abstract
The relation between rotation speed, air pressure and the velocity of air-rotary drilling using the down the hole method is determined in an empirical manner. For the study, velocity measurements are obtained for combinations of the aforementioned parameters during fieldwork for the installation of borehole heat exchangers near Lublin, Poland. The tests consider three drill bit diameters—110, 127 and 140 mm; three rotational speeds—20, 40 and 60 1/min; and three air pressures—16, 20 and 24 bar. The borehole heat exchangers need 100 m deep wells. The lithology consists mainly of loess and clays to 24 m, sand and carbonate rocks to 36 m, and marls and limestone to 100 m. It is found that the highest drilling velocity is achieved when the greatest pressure is applied, while the lowest drilling velocity is connected to the lowest pressure. However, the relation between rotation speed and drilling velocity is more complex, as drilling velocity seems to be more affected by depth. Therefore, lithology can be a major factor. The results may find direct use in drilling, and provide a basis for further studies on the optimization of drilling technology.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".