Effect of Surface Roughness Induced by Laser Powder Bed Fusion Additive Manufacturing in a Mini-Channel Heat Exchanger
Bibliographic record
Abstract
Abstract The Inside-Out Ceramic Turbine (ICT) is a promising microturbine for aeronautics applications. To increase the cycle efficiency and reduce fuel consumption, microturbines must operate under the recuperated Brayton cycle. The addition of a heat exchanger (HEx) increases the weight of the engine and cancels out any fuel savings as compared to a non-recuperated turbine. For this reason, the requirements applied to HEx for aeronautic gas turbines are: low weight and volume, high effectiveness with a low pressure drop, capabilities to endure high pressure and temperature, and low cost. The Laser powder bed fusion (LPBF) opens a new design space for geometries that cannot be realized by conventional methods, but induces high surface roughness. This paper presents experimental and analytical studies of the influence of surface roughness on the performances of a 3D-printed, counterflow, mini-channel HEx, with 1% of the total mass flow rate of the ICT. Results showed that the friction and heat transfer are both increased in the the regime typically defined as laminar compared to the analytical results. The experimental results are in agreement with a 1D heat transfer model when using correlations for high-roughness values from the literature. LPBF is a promising method to manufacture gas turbine parts, but it is crucial to model and incorporate its manufacturing capacities in terms of precision and surface finish to enhance HEx heat transfer and potentially reduce mass.
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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) | 0.001 | 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".