Experimental Study: Effects of the Annulus’ Center Body End Shape on the Performance of Low Mach Number Air-Air Ejector With Entraining Diffuser
Bibliographic record
Abstract
In the present paper, an experimental investigation of the performance of a low mach number round straight air-air ejector with a 4-ring entraining diffuser is reported. The ejector system was mounted on an annular flow wind tunnel. Based on the hydraulic diameter and average velocity and temperature at the nozzle exit, the tunnel provides cold flow at Mach 0.2 with a Reynolds number of 5.2×105 and hot flow at Mach 0.27 with a Reynolds number of 2.6×105. The end shape of the annulus’ center body has major effects on the core separation size and shape that strongly affects the ejector performance. The effects of the annulus’ center body with elliptical and square ends on the ejector pumping, wall static pressure distribution and back pressure were investigated under different flow temperatures and swirl angles: 0°, 10°, 20°, and 30°. These measurements were conducted at 129 mm standoff distance using two different nozzle exit diameters. It was found that for both nozzle exit diameters, using the annulus’ center body with a square end improved the total pumping ratio over its ratio with an elliptical end due to the flatness of the core separation at the nozzle exits. For all configurations tested, the maximum entrainment ratio was observed with 20° swirl angle and the back pressure coefficient decreased as swirl angle increased. Removing the elliptical end, creating the square shape, the flow has more space to spread after the annulus’ center body to give the higher centerline velocity which enhances the flow uniformity at the nozzle and diffuser exits.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".