A computational study of gas flow in a De‐Laval micronozzle at different throat diameters

Lin, Cheng-Xian; Gadepalli, V. V.

doi:10.1002/fld.1868

Cited by 10 publications

(6 citation statements)

References 19 publications

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“…Compared with thrusters of normal size, fluid flow in the micro-thruster chip shows different characteristics due to its large specific surface area and viscous effect at micro-scale. Although there have been many research papers available in the literature about micro-scale fluid flow in micro-channels [16,17] and micro-nozzles [18,19], few have related flow patterns with thrust performance. In this work, micro-thrust force and specific impulse of a VLM were measured, and the two-phase flow patterns were visualized by high speed camera bonded with a microscope.…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation and flow visualization of a MEMS based vaporizing liquid micro-thruster

Cen

2010

Acta Astronautica

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MEMS micro-thruster is promising for future applications in precision formation flying missions. This paper presents performance evaluation and two-phase flow pattern visualization of a vaporized liquid micro-thruster (VLM). Micro-thrust force of several milli-Newtons was measured by a test rig with a lever. Flow patterns in the micro-thruster chip were visualized by a high speed camera bonded with a microscope. We found that flow patterns influenced its specific impulse and there were several types of flow boiling patterns in the thruster chip. Thrust instability was discussed as well. The results are helpful to understand flow characteristics of a VLM and improve its performance.

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Section: Introductionmentioning

confidence: 99%

Performance evaluation and flow visualization of a MEMS based vaporizing liquid micro-thruster

Cen

2010

Acta Astronautica

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“…Moreover, an optimized propulsion nozzle for high injection and ejection efficiency would result in superior performance. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] The proposed micro-Ro-boat primarily requires wiring connections for power transmission. In this study, a thin gold wire (25 m diameter) is used for the power connection of the micro-Ro-boat, but it sometimes obstructed the movement because of the very light weight of the micro-Ro-boat and the large pulling force of the wire.…”

Section: Discussionmentioning

confidence: 99%

Micro-Electro-Mechanical-Systems-Based Micro-Ro-Boat Utilizing Steam as Propulsion Power

Choi

Lee

et al. 2012

Jpn. J. Appl. Phys.

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We report the design and fabrication of a micro-electro-mechanical-systems (MEMS)-based microactuator, that floats on the surface of water and is driven by steam. We named the actuator “micro-Ro-boat”, a compound word created from the words “robot” and “boat”. The MEMS-based micro-Ro-boat utilizes steam as the propulsion power, giving it a high speed and long lifetime. A hydrophobic surface has been utilized for the wing of the actuator to enhance the buoyancy. Instead of using gas or fuel, the proposed micro-Ro-boat utilizes steam form electrically heated water. The velocity of the micro-Ro-boat is in the range of 0.5–2 cm/s and the maximum loading capability for a device size of 10 ×10 mm2 is 0.4 g.

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“…For throat diameters varying from 1.2 to 1.8 mm, a better velocity performance is presented under a throat diameter of 1.2 mm, and it gradually deteriorates as the throat diameter increases. It reported that a decrease in throat diameter helps to improve the gas velocity inside the Laval structure [29,36]. Thus, due to the decrease in the atomizing core acceleration performance of the NTN resulting from the increase in throat diameter, the injection power and atomization energy weaken, which results in a decrease in the droplet velocity.…”

Section: Influence Of the Throat Diametermentioning

confidence: 99%

Influence of atomizing core on droplet dynamic behavior and machining characteristics under synergistically enhanced twin-fluid spray

Chen

Gao

et al. 2020

Int J Adv Manuf Technol

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The droplet dynamic behavior of spraying during the manufacturing process affects tool life, cooling, and lubrication. A detailed understanding of droplet dynamic behavior is required to improve the surface quality while reducing the cutting fluid consumption. In this study, quantitative measurements for droplet diameter, number concentration, and axial velocity were carried out through a phase Doppler particle analyzer technique. The droplet characteristic spatial distributions of a standard twin-fluid nozzle (STN) and a novel twin-fluid nozzle (NTN) under different gas-to-liquid mass ratio (GLR) values were analyzed in detail. The results showed that the high-speed internal gas flow of an atomizing core has a significant effect on improving the synergistically enhanced atomization behavior, and more smaller droplets and an increased droplet momentum are easily obtained. Furthermore, a better spatial distribution of atomization characteristics can be achieved under a higher GLR of 4.3%. Furthermore, the effects of the novel atomizing core structural parameters on the droplet mean velocity spatial distribution, droplet turbulence, and root mean square velocity fluctuation were investigated. The results also showed that the improved NTN can effectively improve the spray atomization performance and droplet dynamic characteristics. In addition, comparative studies of the effect of the atomizing core structure on the machining performance were performed. Compared with the STN, the improved NTN achieves a significant reduction in cutting temperature, tool wear, and surface roughness of 17.25%, 33.96%, and 37.83%, respectively, owing to the better droplet dynamic characteristics and spatial distribution of spray atomization characteristics.

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A computational study of gas flow in a De‐Laval micronozzle at different throat diameters

Cited by 10 publications

References 19 publications

Performance evaluation and flow visualization of a MEMS based vaporizing liquid micro-thruster

Performance evaluation and flow visualization of a MEMS based vaporizing liquid micro-thruster

Micro-Electro-Mechanical-Systems-Based Micro-Ro-Boat Utilizing Steam as Propulsion Power

Influence of atomizing core on droplet dynamic behavior and machining characteristics under synergistically enhanced twin-fluid spray

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