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Development of a Laval nozzle for a cold gas propulsion system

2018· article· en· W2891678813 on OpenAlexaboutno aff
Oana Dumitrescu, Bogdan Gherman, Traian Tipa

Bibliographic record

VenueIOP Conference Series Materials Science and Engineering · 2018
Typearticle
Languageen
FieldEngineering
TopicRocket and propulsion systems research
Canadian institutionsnot available
Fundersnot available
KeywordsNozzlePropulsionAerospace engineeringMach numberRocket engine nozzleSupersonic speedJet propulsionThermalJet (fluid)Mechanical engineeringSpacecraft propulsionMechanicsEngineeringPhysicsMeteorology

Abstract

fetched live from OpenAlex

This paper presents a study regarding the calculation and design of a Laval nozzle, and its influence on the performances obtained. For this research, numerical simulation were conducted using the commercial software ANSYS CFX to verify the geometry and to compare it with the analytical results. This study is part of a research project that develops an advanced solar thermal propulsion system; the main purpose is to increase the operation life of a satellite using focused solar light. Two geometries are analyzed in this paper: one with a cone shape and the other generated using the characteristics method. The working fluid is nitrogen gas, which was used due to its inert properties and high molar mass. For the numerical simulations an exterior domain has been taking into account, to capture the jet and to observe how is evolving into the atmosphere. Several cases were studied; temperature was the main parameter varied from one case to another. As a result of the numerical simulations, it was found that the nozzle shape and temperature at the inlet to the convergent section influences performance of the propulsion system in a significant manner. Mach diamonds form because of the supersonic exhaust of the nozzle, and can be seen how their intensity is decreasing in magnitude near the domain outlet.

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 machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.002
Threshold uncertainty score0.005

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.001
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0020.000

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.

Opus teacher head0.027
GPT teacher head0.248
Teacher spread0.221 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

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".

Quick stats

Citations5
Published2018
Admission routes1
Has abstractyes

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