Injecteur

Résumé

Un injecteur est un dispositif permettant l'apport de matières gazeuses ou liquides dans une machine. Il existe plusieurs types d'injecteurs. Machine à vapeur L'injecteur Giffard est un appareil utilisant l'énergie de la vapeur pour alimenter la chaudière en eau dans les moteurs à vapeur, également utilisé dans le procédé Triger. Injecteur de moteur L'injecteur permet l'apport du carburant dans la chambre de combustion des moteurs Diesel et dans certains moteurs à essence. La pompe à carburant alimente le filtre à essence qui retient les impuretés. Le combustible est ensuite pulvérisé dans chaque cylindre, par l'injecteur sous forme de micro gouttelettes, permettant une combustion optimale. Ce phénomène peut être amplifié grâce à une turbine amplifiant la dispersion des gouttelettes. La vaste majorité des moteurs de voitures l'utilise en remplaçant le carburateur, ou encore dans les turboréacteurs d'avions. Injecteur de chaudière à fioul

Source officielle

https://fr.wikipedia.org/wiki/Injecteur

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 (21)

Publications associées

Chargement

Personnes associées (1)

Personnes associées

Chargement

Unités associées (2)

Unités associées

Chargement

Concepts associés (13)

Concepts associés

Chargement

Cours associés (15)

Cours associés

Chargement

Séances de cours associées (19)

Séances de cours associées

Chargement

Effect of periodic gas-puffs on drift-tearing modes in ADITYA/ADITYA-U tokamak discharges

Harshita Raj, Abhijit Sen

The effect of a periodic train of short gas-puff pulses on the rotation frequency and amplitude of drift-tearing modes has been studied in ADITYA/ADITYA-U tokamak. The short gas puffs, injecting approximately similar to 10(17)-10(18) molecules of fuel gas (hydrogen) at one toroidal location, are found to concomitantly decrease the drift-tearing mode rotation frequency and the mode amplitude during the period of injection and then recover back to its initial values when the gas pulse is over. This leads to a periodic modulation of the rotation frequency and amplitude of the drift-tearing modes that is correlated with the periodicity of the gas pulse injection. The underlying mechanism for this change in the mode characteristic appears to be related to gas puff induced change in the radial profile of the plasma pressure in the edge region that brings about a reduction in the diamagnetic drift frequency. Detailed experimental measurements and BOUT++ code simulations support such a reduction in diamagnetic drift frequency. Our results reveal a close interaction between the edge dynamics and core MHD phenomena in a tokamak that could help us better understand the rotation dynamics and amplitude pulsations of magnetic islands.

2020

Chargement

Gas-puff induced cold pulse propagation in ADITYA-U tokamak

Rohit Kumar, Ankit Kumar, Harshita Raj, Abhijit Sen

Short bursts (similar to 1 ms) of gas, injecting similar to 10(17)-10(18) molecules of hydrogen and/or deuterium, lead to the observation of cold pulse propagation phenomenon in hydrogen plasmas of the ADITYA-U tokamak. After every injection, a sharp increase in the chord-averaged density is observed followed by an increase in the core electron temperature. Simultaneously, the electron density and temperature decrease at the edge. All these observations are characteristics of cold pulse propagation due to the pulsed gas application. The increase in the core temperature is observed to depend on the values of both the chord-averaged plasma density at the instant of gas-injection and the amount of gas injected below a threshold value. Increasing the amount of gas-puff leads to higher increments in the core-density and the core-temperature. Interestingly, the rates of rise of density and temperature remain the same. The gas-puff also leads to a fast decrease in the radially outward electric field together with a rapid increase in the loop-voltage suggesting a reduction in the ion-orbit loss and an increase in Ware-pinch. This may explain the sharp density rise, which remains mostly independent of the toroidal magnetic field and plasma current in the experiment. Application of a subsequent gas-puff before the effect of the previous gas-pulse dies down, leads to an increase in the overall electron density and consequently the energy confinement time.

2021

Chargement

The technology gap between liquid and gaseous fuels presents an obstacle in realising the environmental and performance potential of CNG vehicles. Therefore a gaseous fuel injector has been developed to cope with the considerable larger volume flow rated required for a gaseous fuel without additional penalties in response time. This injector has demonstrated a significant potential to reduce emissions from natural gas powered engines during transient operation.

1995

Chargement