Experimental scaling laws for the discharge oscillations and performance of Hall thrusters

2022 ◽  
Vol 131 (1) ◽  
pp. 013304
Author(s):  
V. Giannetti ◽  
A. Piragino ◽  
C. A. Paissoni ◽  
E. Ferrato ◽  
D. Estublier ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Hall Thrusters ◽  
And Performance

A Study of the Effects of Scaling on Structural Integrity Assessment and Feasibility of Physical Validation

2016 ◽  
Author(s):  
Paulo Orrock ◽  
Christopher E. Truman
Keyword(s):  
Scaling Laws ◽  
Structural Integrity ◽  
Driving Forces ◽  
Stress Fields ◽  
Complex Nature ◽  
Statistical Nature ◽  
Integrity Assessment ◽  
And Performance ◽  
Scaled Models ◽  
Random Nature

For nuclear welded components the complex nature of the stresses involved means it is often advantageous to produce mock-ups in order that the structural integrity and performance may be assessed. The weight and size of these components can make the production of mock-ups prohibitively expensive and impractical, and so the use of scaled models is considered here. The scaling laws encountered affecting the applied loads, residual stresses and crack driving forces that are of interest are investigated using numerical analyses and finite element simulations. Of particular interest is the physical validation of these laws and the statistical difficulties that may be encountered. The scaling of applied loads required to obtain the same residual stress fields and stress intensity factors are investigated using simulated four point bends. The statistical nature of fracture introduces uncertainty into fracture measurements which this paper takes into consideration in preparation for physical validation, ensuring that the random nature of fracture will not make the described laws impractical to validate.

Scaling laws and performance improvements of integrated biosensor microarrays with multi-pixel per spot

2012 ◽  
Vol 166-167 ◽  
pp. 184-192 ◽  
Author(s):  
N. Couniot ◽  
A. Afzalian ◽  
D. Flandre
Keyword(s):  
Scaling Laws ◽  
Performance Improvements ◽  
And Performance

scholarly journals Evaluation of a Mesoscale Thermal Actuator in Open and Closed Operating Cycles

2019 ◽  
Author(s):  
Sindhu Preetham Burugupally
Keyword(s):  
Heat Input ◽  
Scaling Laws ◽  
Lumped Parameter Model ◽  
Thermal Actuator ◽  
Closed Cycle ◽  
Two Phase ◽  
Practical Applications ◽  
Thermal Actuators ◽  
Large Force ◽  
And Performance

Thermal-based actuators are known for generating large force and displacement strokes at mesoscale (millimeter) regime. In particular, two-phase thermal actuators are found to benefit from the scaling laws of physics at mesoscale to offer large force and displacement strokes; but they have low thermal efficiencies. As an alternative, a combustion-based thermal actuator is proposed and its performance is studied in both open and closed cycle operations. Through a physics-based lumped-parameter model, we investigate the behavior and performance of the actuator using a spring-mass-damper analogy and taking an air standard cycle approach. Three observations are reported: (1) the mesoscale actuator can generate peak forces of up to 400 N and displacement strokes of about 16 cm suitable for practical applications; (2) an increase in heat input to the actuator results in increasing the thermal efficiency of the actuator for both open and closed cycles; and (3) for a specific heat input, both the open and closed cycle operations respond differently \textemdash different stroke lengths, peak pressures, and thermal efficiencies.

A Study of the Effects of Scaling on Structural Integrity Assessment

2015 ◽  
Author(s):  
Paulo Orrock ◽  
David J. Smith ◽  
Christopher E. Truman
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Scaling Laws ◽  
Structural Integrity ◽  
Driving Forces ◽  
Scaling Law ◽  
Stress Fields ◽  
Complex Nature ◽  
Integrity Assessment ◽  
And Performance

For nuclear welded components the complex nature of the residual stresses involved means it is often advantageous to produce mock-ups in order that the structural integrity and performance may be assessed. The weight and size of these components can make the production of mock-ups prohibitively expensive, and so the use of scaled models is considered here. Numerical analysis and finite element simulations have been carried out to investigate the scaling laws encountered affecting the applied loads, stress fields and crack driving forces that are of interest in the full sized component. To illustrate the effects of scaling we consider the introduction of a residual stress through prior plastic deformation in rectangular beams of different sizes. A simple scaling law provides the loads required to introduce the same magnitude and distribution of residual stresses in different sized specimens. This is pertinent to uncracked beams. In contrast, if a crack is introduced this scaling law is no longer applicable and the stress intensity factor associated with residual and applied stresses differ for different sized specimens. Alternatively, to create the same crack driving force in different sized specimens different initial residual stress fields are required. The implications of these findings are discussed in the context of future work.

Performance Prediction and Scaling Laws of Circular Dielectric Elastomer Membrane Actuators

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Steffen Hau ◽  
Alexander York ◽  
Gianluca Rizzello ◽  
Stefan Seelecke
Keyword(s):  
Scaling Laws ◽  
Large Strain ◽  
Low Cost ◽  
Computationally Efficient ◽  
Performance Scaling ◽  
Out Of Plane ◽  
And Performance ◽  
High Flexibility ◽  
Force Displacement ◽  
Dielectric Elastomer Membrane

For a number of emerging mechatronics applications, dielectric elastomers (DEs) appear as a more energy efficient, lightweight, and low-cost solution with respect to established actuation technologies based, e.g., on solenoids or pneumatic cylinders. In addition to large strain, low power consumption, and high flexibility, DE actuators (DEA) are also highly scalable. Since DE membranes can be easily manufactured in different sizes and shapes, an effective approach to scale their performance is based on properly designing the material geometry. Clearly, to perform an optimal scaling the relation between material geometry and performance has to be properly investigated. In this paper, performance scaling by means of geometry is studied for circular out-of-plane (COP) DEAs. Such actuators consist of a silicone elastomer membrane sandwiched between two electrodes (carbon black silicone mixture). DEAs with six different geometries are manufactured, and a model-based strategy is used to find an experimental relationship between geometry and electro-mechanical behavior. In addition, an effective and computationally efficient method for predicting force–displacement characteristics of different geometries is presented. The proposed method allows to easily adapt DEAs to different applications in terms of stroke and force requirement, while minimizing at the same time both characterization and prototyping effort.

Scaling laws and performance limitations of power turn-off devices

2003 ◽  
Author(s):  
A.A. Jaecklin ◽  
B. Adam
Keyword(s):  
Scaling Laws ◽  
Performance Limitations ◽  
And Performance

scholarly journals Small Hall Effect Thruster with 3D Printed Discharge Channel: Design and Thrust Measurements

Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 227
Author(s):  
Ethan P. Hopping ◽  
Wensheng Huang ◽  
Kunning G. Xu
Keyword(s):  
3D Printing ◽  
Hall Effect ◽  
Discharge Channel ◽  
Low Cost ◽  
Hall Thrusters ◽  
Hall Effect Thruster ◽  
Sustained Operation ◽  
3D Printed ◽  
Multiple Materials ◽  
And Performance

This paper presents the design and performance of the UAH-78AM, a low-power small Hall effect thruster. The goal of this work is to assess the feasibility of using low-cost 3D printing to create functioning Hall thrusters, and study how 3D printing can expand the design space. The thruster features a 3D printed discharge channel with embedded propellant distributor. Multiple materials were tested including ABS, ULTEM, and glazed ceramic. Thrust measurements were obtained at the NASA Glenn Research Center. Measured thrust ranged from 17.2–30.4 mN over a discharge power of 280 W to 520 W with an anode ISP range of 870–1450 s. The thruster has a similar performance range to conventional thrusters at the same power levels. However, the polymer ABS and ULTEM materials have low temperature limits which made sustained operation difficult.

scholarly journals Ionization, Plume Properties, and Performance of Cylindrical Hall Thrusters

2010 ◽  
Vol 38 (4) ◽  
pp. 1052-1057 ◽  
Author(s):  
Kevin D Diamant ◽  
James E Pollard ◽  
Yevgeny Raitses ◽  
Nathaniel J Fisch
Keyword(s):  
Hall Thrusters ◽  
And Performance
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