Compresseur à spirale

Résumé

vignette|Illustration du fonctionnement d'un compresseur à spirale. Un compresseur à spirale, également appelé compresseur spiro-orbital, est un type de compresseur mécanique destiné à comprimer de l'air ou des fluides réfrigérants. Ces équipements se rencontrent notamment dans des climatisations, des réfrigérateurs, voire la construction automobile et les pompes à vide. Ce principe a été breveté par le français Léon Creux en 1905 comme moteur rotatif à vapeur avec deux spirales co-orbitales. Il repose sur deux pales imbriquées qui peuvent être des spirales d'Archimède, des développantes ou des courbes hybrides. L'une des spirales est souvent fixe tandis que l'autre orbite autour de l'axe central sans tourner afin de comprimer des poches de fluide entre les spirales. Le mouvement orbital peut être communiqué par un arbre décentré mais il est indispensable d'empêcher la spirale de tourner sur elle-même. Une autre réalisation du dispositif consiste à faire orbiter les deux spirales de m

Source officielle

https://fr.wikipedia.org/wiki/Compresseur_%C3%A0_spirale

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (9)

Publications associées

Chargement

Personnes associées (2)

Personnes associées

Chargement

Unités associées (1)

Unités associées

Chargement

Concepts associés (1)

Concepts associés

Chargement

Cours associés (3)

Cours associés

Chargement

Séances de cours associées (6)

Séances de cours associées

Chargement

, ,

Although robustness is an important consideration to guarantee the performance of designs under deviation, systems are often engineered by evaluating their performance exclusively at nominal conditions. Robustness is sometimes evaluated a posteriori through a sensitivity analysis, which does not guarantee optimality in terms of robustness. This article introduces an automated design framework based on multiobjective optimisation to evaluate robustness as an additional competing objective. Robustness is computed as a sampled hypervolume of imposed geometrical and operational deviations from the nominal point. In order to address the high number of additional evaluations needed to compute robustness, artificial neutral networks are used to generate fast and accurate surrogates of high-fidelity models. The identification of their hyperparameters is formulated as an optimisation problem. In the frame of a case study, the developed methodology was applied to the design of a small-scale turbocompressor. Robustness was included as an objective to be maximised alongside nominal efficiency and mass-flow range between surge and choke. An experimentally validated 1D radial turbocompressor meanline model was used to generate the training data. The optimisation results suggest a clear competition between efficiency, range and robustness, while the use of neural networks led to a speed-up by four orders of magnitude compared to the 1D code.

CAMBRIDGE UNIV PRESS2022

Chargement

Dimensionless correlations and performance maps of scroll expanders for micro-scale Organic Rankine Cycles

Luis Carlos Mendoza Toledo, Violette Mounier, Luis Eric Olmedo Ocampo, Jürg Alexander Schiffmann

In the endeavor towards distributed power systems, not seasonal-dependent micro-power generation technologies are expected to integrate the energy scenario in the years to come. In this context, the Organic Rankine Cycle (ORC) in the (1e10) KWe scale has chronically lacked a suitable expansion device, hindering its market attractiveness. As scroll expanders have been pointed out as strong potential candidates, performance correlations and pre-design maps based on a review and analysis of published experimental data are presented. A dimensionless approach based on the traditional Ns, Ds dimen-sionless numbers stemming from turbomachinery has been chosen for greater generality. In addition, the lubricating oil mass fraction effect on the scroll expander performance has been included. The generated maps contribute to accelerating the pre-design phases at the system and component level with beneficial effects for the overall development process. Basic geometry and size characteristics are considered as well, acknowledging their importance in micro-power embedded applications; these considerations are illustrated in a passenger car waste-heat recovery case study. Findings suggest that optimized scroll expanders may potentially reach very interesting nominal electric isentropic efficiencies (up to 80% for an oil lubricated scroll expander).

2018

Chargement

Analysis of a Combined Absorption Cycle for Power and Cooling Production Using a Novel Oil-Free Co-Rotating Scroll Expander

Luis Carlos Mendoza Toledo, Jürg Alexander Schiffmann

This paper presents the integration of a novel scroll expander into a combined power and cooling cyclethat can be driven by low grade heat sources such as solar and waste heat. The scroll device used here is based on a co-rotating technology which allows to work without internal lubrication. The mathematical model adopted for the cycle incorporates a simplified semi-empirical model that predicts the performance of the scroll expander. Ammonia-water has been selected as the working fluid because of its nature-friendliness. Some operating parameters such as the heat source (155-205°C), sink (16-34°C) and chilled water (8-18°C) temperatures have been varied to investigate the behaviour of the cycle. The results show that increasing the heat source temperature is beneficial to power generation but detrimental to cooling production. However, increasing the sink temperature is favourable for both power and cooling modes. Increasing the chilledwater temperature is detrimental to both outputs. It was found that at the nominal conditions of heat source, sink and chilled water temperatures of 180°C, 27°C and 7°C respectively and an expander rotational frequency of116.7 Hz; the cycle generated 87 kW of net mechanical power and 562 kW of cooling while the effective first law and exergetic efficiencies were 18.6 and 58.8% respectively.

2016

Chargement