scholarly journals Validating a Reduced-Order Model for Synthetic Jet Actuators Using CFD and Experimental Data

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 67 ◽  
Author(s):  
Tim Persoons ◽  
Rick Cressall ◽  
Sajad Alimohammadi
Keyword(s):  
Synthetic Jet ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
Driving Voltage ◽  
Cavity Pressure ◽  
Order Model ◽  
Reduced Order ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Jet Velocity

Synthetic jet actuators (SJA) are emerging in various engineering applications, from flow separation and noise control in aviation to thermal management of electronics. A SJA oscillates a flexible membrane inside a cavity connected to a nozzle producing vortices. A complex interaction between the cavity pressure field and the driving electronics can make it difficult to predict performance. A reduced-order model (ROM) has been developed to predict the performance of SJAs. This paper applies this model to a canonical configuration with applications in flow control and electronics cooling, consisting of a single SJA with a rectangular orifice, emanating perpendicular to the surface. The practical implementation of the ROM to estimate the relationship between cavity pressure and jet velocity, jet velocity and diaphragm deflection and applied driving voltage is explained in detail. Unsteady Reynolds-averaged Navier Stokes computational fluid dynamics (CFD) simulations are used to assess the reliability of the reduced-order model. The CFD model itself has been validated with experimental measurements. The effect of orifice aspect ratio on the ROM parameters has been discussed. Findings indicate that the ROM is capable of predicting the SJA performance for a wide range of operating conditions (in terms of frequency and amplitude).

scholarly journals Correction: Persoons, T.; Cressall, R.; Alimohammadi, S. Validating a Reduced-Order Model for Synthetic Jet Actuators Using CFD and Experimental Data. Actuators 2018, 7, 67

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 16
Author(s):  
Tim Persoons ◽  
Rick Cressall ◽  
Sajad Alimohammadi
Keyword(s):  
Experimental Data ◽  
Synthetic Jet ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Synthetic Jet Actuators ◽  
Jet Actuators

The authors wish to make the following corrections to this paper [...]

scholarly journals Reduced-Order Model for Efficient Simulation of Synthetic Jet Actuators

AIAA Journal ◽  
2005 ◽  
Vol 43 (2) ◽  
pp. 357-369 ◽  
Author(s):  
N. K. Yamaleev ◽  
M. H. Carpenter ◽  
Frederick Ferguson
Keyword(s):  
Synthetic Jet ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Synthetic Jet Actuators ◽  
Efficient Simulation ◽  
Jet Actuators

scholarly journals LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review

2017 ◽  
Author(s):  
Matteo Chiatto ◽  
Francesco Capuano ◽  
Gennaro Coppola ◽  
Luigi de Luca
Keyword(s):  
Piezoelectric Element ◽  
Synthetic Jet ◽  
Orifice Diameter ◽  
Cavity Pressure ◽  
Synthetic Jet Actuators ◽  
Lumped Element ◽  
Air Jet ◽  
Jet Actuators ◽  
Jet Velocity ◽  
Design And Manufacture

In the last decades synthetic jet actuators have gained much interest among the flow control techniques due to their short response time, high jet velocity and absence of traditional piping, that matches the requirements of reduced size and low weight. A synthetic jet is generated by the diaphragm oscillation (generally driven by a piezoelectric element) in a relatively small cavity, producing periodic cavity pressure variations associated with cavity volume changes. The pressured air exhausts through an orifice, converting diaphragm electrodynamic energy into jet kinetic energy. This review paper faces the development of various lumped-element models (LEMs) as practical tools to design and manufacture the actuators. LEMs can quickly predict device performances such as the frequency response in terms of diaphragm displacement, cavity pressure and jet velocity, as well as the efficiency of energy conversion of input Joule power into useful kinetic power of air jet. The actuator performance is analyzed also by varying typical geometric parameters such as cavity height and orifice diameter and length, through a suited dimensionless form of the governing equations. A comprehensive and detailed physical modeling aimed to evaluate the device efficiency is introduced, shedding light on the different stages involved in the process. Overall, the influence of the coupling degree of the two oscillators, the diaphragm and the Helmholtz’s one, on the device performance is discussed throughout the paper.

The performance of round synthetic jets in quiescent flow

2006 ◽  
Vol 110 (1108) ◽  
pp. 385-393 ◽  
Author(s):  
M. Jabbal ◽  
J. Wu ◽  
S. Zhong
Keyword(s):  
Near Field ◽  
Jet Flow ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Operating Conditions ◽  
Stroke Length ◽  
Synthetic Jet Actuators ◽  
Macro Scale ◽  
Jet Actuators ◽  
The Impact

AbstractPIV measurements in the near-field region of a jet flow emanating from a round synthetic jet actuator into quiescent air were conducted over a range of operating conditions. The primary purpose of this work was to investigate the nature of synthetic jets at different operating conditions and to examine the jet flow parameters that dictate the behaviour of synthetic jet actuators. The effects of varying diaphragm displacement and oscillatory frequency for fixed actuator geometry were studied. It was observed that the characteristics of synthetic jets are largely determined by the Reynolds number and stroke length. An increase in the former is observed to increase the strength of consecutive vortex rings that compose a synthetic jet, whereas an increase in the latter results in an increase in relative vortex ring spacing and for further increases in stroke length, shedding of secondary vortices. Correlations were also made between the operating parameters and the performance parameters most effective for flow control and which therefore determine the impact of a synthetic jet on an external flow. Relations of time-averaged dimensionless mass flux, momentum flux and circulation with the jet flow conditions were established and found to widely support an analytical performance prediction model described in this paper. It is anticipated that the experimental data obtained in this study will also contribute towards providing a PIV database for macro-scale synthetic jet actuators.

New Swash Plate Damping Model for Hydraulic Axial-Piston Pump

1999 ◽  
Vol 123 (3) ◽  
pp. 463-470 ◽  
Author(s):  
X. Zhang ◽  
J. Cho ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Open Loop ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Order Model ◽  
Nonlinear Simulation ◽  
Reduced Order ◽  
Swash Plate ◽  
Axial Piston

A new, open-loop, reduced order model is proposed for the swash plate dynamics of an axial piston pump. The difference from previous reduced order models is the modeling of a damping mechanism not reported previously in the literature. An analytical expression for the damping mechanism is derived. The proposed reduced order model is validated by comparing with a complete nonlinear simulation of the pump dynamics over the entire range of operating conditions.

Bimorph-driven synthetic jet actuators optimized for various piezoelectric materials using a low-order model

2017 ◽  
Author(s):  
Tianliang Yu ◽  
George A. Lesieutre ◽  
Steven F. Griffin ◽  
Daniel P. Brzozowski ◽  
Aaron M. Sassoon
Keyword(s):  
Piezoelectric Materials ◽  
Synthetic Jet ◽  
Order Model ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Low Order

Solenoid Damping of the Pilot Poppet in a Forced-Feedback Metering Poppet Valve

2007 ◽  
Author(s):  
C. Harvey O. Cline ◽  
Roger Fales
Keyword(s):  
Dynamic Response ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
The Self ◽  
Hydraulic Fluid ◽  
Order Model ◽  
Reduced Order ◽  
Poppet Valve ◽  
Spool Valves ◽  
Poppet Valves

Forced-feedback metering poppet valves offer several advantages over spool valves as metering elements in hydraulic circuits. Despite these advantages, dynamic instabilities in their performance could limit their acceptance in this role. The pilot poppet damping is a source of uncertainty in dynamic response at certain operating conditions. Presently, in the forced-feedback metering poppet valve, the pilot poppet is damped by the flow of hydraulic fluid through a channel or orifice running through the poppet. Here, it is proposed that the solenoid be used to provide damping to the pilot poppet. The damping input to the solenoid is determined using the pilot poppet velocity. In practice, this is a readily unavailable variable and is estimated according to the self-sensing actuator concept. The proposed damping method is developed and analyzed in simulations. Simulations development and analysis occurred via a simplified, reduced order model of the pilot poppet stage.

scholarly journals An Object-Oriented R744 Two-Phase Ejector Reduced-Order Model for Dynamic Simulations

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1282
Author(s):  
Michal Haida ◽  
Rafal Fingas ◽  
Wojciech Szwajnoch ◽  
Jacek Smolka ◽  
Michal Palacz ◽  
...  
Keyword(s):  
Dynamic Simulation ◽  
Object Oriented ◽  
Operating Conditions ◽  
Reduced Order Model ◽  
Refrigeration System ◽  
Order Model ◽  
Two Phase ◽  
Dynamic Simulations ◽  
Climate Zones ◽  
Reduced Order

The object-oriented two-phase ejector hybrid reduced-order model (ROM) was developed for dynamic simulation of the R744 refrigeration system. OpenModelica software was used to evaluate the system’s performance. Moreover, the hybrid ROM results were compared to the results given by the non-dimensional and one-dimensional mathematical approaches of the R744 two-phase ejector. Accuracy of all three ejector models was defined through a validation procedure for the experimental results. Finally, the dynamic simulation of the hybrid ROM ejector model integrated with the R744 refrigeration system was presented based on the summer campaign at three different climate zones: Mediterranean, South American and South Asian. The hybrid ROM obtained the best prediction of ejector mass flow rates as compared with other ejector models under subcritical and transcritical operating conditions. The dynamic simulations of the R744 ejector-based system indicated the ejector efficiency variations and the best efficiency at the investigated climate zones. The coefficient of performance (COP) varied from 2.5 to 4.0 according to different ambient conditions. The pressure ratio of 1.15 allowed a more stabilised system during the test campaign with an ejector efficiency from 20% to over 30%.

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