Synthetic Jet Actuators used in Cleaning Automotive Sensor
Engineering and Construction
Synthetic Jet Actuators used in Cleaning Automotive Sensor
Synthetic Jet Actuator (SJA) has been researched under Active flow Control (AFC) which involves the modifications of a control field by the use of control devices known as the actuators. The efficient control system is aimed at improving energy efficiency, especially in the automotive industry. Several methods have been implemented as a result of the evolution of technology. The most common methods for SJA include electromagnetic actuation, plasma and piezoelectric. One such method is the use of plasma synthetic jet actuators (PSJAs). The PSJAs is the most preferred method because it produces high velocity as well as high frequency and it is commonly applied in the cases of high-Reynolds number (Pointer et al., 2018). SJA has also been utilized and applied in several devices such as the jet thrust vectoring and heat transfer argumentation among others. Therefore, the report presents the application of the SJA in automotive sensors cleanings for LIDAR and camera. The report also outlines both the advantages and disadvantages of using synthetic jet actuators. The SJA has been studied in experimentally and numerically. Some of the measurement techniques that have been carried out on the devices include the Particle Image Velocimetry (PIV) as well as the Laser Doppler Velocimetry (LDV). The other processes involve conducting the computational fluid dynamics (CFD) by the use of some parameters such as the Reynolds number and the use of other techniques such as the Large Eddy Simulations (LES), among others (Chiatto, Capuano, Coppola & De Luca, 2017). The cleaning process is an area of application of the devices especially by the use of sensors.
In the actuation method, the sufficient amount of volume of air should be sufficient enough to allow the maximization of the velocity in the synthetic jet. The volume of displacement can also be achieved by several means of which each has both the advantages and disadvantages by focusing on the suitability as well as the application of the actuator and in this case, the focus is on the application in the cleaning process. The methods which are commonly applied include the piezoelectric as well as the electromagnetic actuation.
For the case of piezoelectric transducers, it consists of a piezoelectric patch which is bonded to a metal structure and allows the oscillation of the voltage. The advantage of the method is the compact size which makes it robust and easily utilized for its purpose. The piezoelectric method has also a diaphragm thickness which is less than half a millimeter (Jeyalingam, 2018). It also consumes less amount of power because it has unique types of capacitive natures. On the other hand, the disadvantages of the method include the need to operate mechanical resonance frequency for one to obtain displacements which might reduce the lifespan of the diaphragm. The piezoelectric transducer has also a high acoustic output.
On the other hand, the electromagnetic actuation can also be applied in the cleaning process and consists of the vibration generators as well as the magnetic shakers 9 Jeyalingam, 2018). The method has advantages such as it has a low range of actuation frequencies including a large diaphragm which makes it effective for performing its functions. The displacement of the electromagnetic is dependent on the specifications of the manufacturer such as the voltage and actuation frequency. However, the method can be less attractive for various applications, especially for use in aerospace because of factors such as the large mass and sizes of the transducers as well as the high heat output due to the resistive coil.
The other benefits of the synthetic jet actuator include; they require no external source of flow and can be made available for different types of drivers and sizes. On the other hand, the velocities are also limited to low speeds, which makes them difficult for application in some cases.
The synthetic jet actuators have other additional benefits that prove them effective for several applications. The SJA are small devices which can be integrated easily in other devices such as camera and LIDAR for use in the application for several purposes. The devices are also small and flexible and hence can easily be moved to the sensor which is a contributing factor towards improving the accuracies of the utilization of the devices. The devices are also simple and can easily be manufactured using simplified procedures thereby saving on the cost and time (Jeyalingam, 2018). The SJA devices can also be used to serve several purposes such as the removal of the raindrops and there is no need for the use of fluid. Additionally, the SJA devices have high efficiency when compared to the sensor which enhances the performance of its functions. The jump has a better packing approach and can easily be moved to the sensor thereby reducing the possibility of pressure drop which is an important factor.
On the other hand, SJA methods have other several limitations which include that the membrane does not last for a long time which increases the issues of additional costs notably on the maintenance. In some instances, the highest pressure that can be achieved while cleaning is closely related to its size. Therefore, the small devices are likely to produce small pressures which might not be good for its purpose.
One of the specifications that control the process of cleaning or other application in the automotive industry is reliability. The reliability of the devices is important in establishing the working mechanism of the devices (ATS, 2011). However, in some cases, some manufacturers do not specify the reliability data especially at higher temperatures.
Figure 1: The reliability of the synthetic jet actuators in comparison with other devices (ATS, 2011)
The electric spark increases lead to the production of energy which eventually increases the temperature and pressure of the devices (MDPI, 2020). The distribution of pressure and the temperature becomes non-uniform because of the activity of the energy discharges. The high-pressure air that passes through the orifice is then used in the conversion of kinetic energy. The termination of the negative differential pressure takes place at the throat of the actuator.
Figure 2: Relationship between cavity pressure and jet pressure (MDPI, 2020)
Applications of Synthetic Jet Actuators
The SJA is commonly applied for brief current and the electronic cooling in the aerospace. It is also used in the control of the circulation of gases and air in the heating, ventilation and air conditioning systems (HVAC). The SJA has also a wide range of applications especially in the active flow control for areas such as the heat transfer, control flow at low match numbers and the reduction of the drag turbulent boundary layers (Dahalan, Mansor & Ali, 2012). The devices are also dominantly applied in the changing effect of the airfoil camber as well as the manipulation of the vortex flow.
Industry leader’s summary
Leaders recognize the importance and application of SJA in various functions. For instance, one of the leaders acknowledges the existence of SJA and its role played in the active flow control. The devices are powerful and have the ability to modify the natural behavior and manipulating the flow which results in the variation of dynamics forces. The applications can be in several areas such as flow control, the transfer of heat and mixing enhancement among others. The other different types of actuators have been tested and proven for application in various engineering fields. An example of such an application is in the cleaning process by the use of sensors. The devices which are commonly considered include the piezoelectric elements, plasma actuators and loudspeakers among other applications.
In conclusion, the research describes the applications of the Synthetic Jet Actuators especially in the cleaning process by the use of devices such as cameras and LIDAR. The process has been tested and proven to be more effective and for use in the cleaning of the automotive industry. The Synthetic Jet Actuators can substitute the traditional methods of cleaning since it involves the utilization of current technologies. The paper also discusses the advantages and disadvantages of SJA devices. The advantages of the method outweigh the disadvantages. Due to its major benefits, the SJA devices are most preferred and gained importance in various fields of engineering. Some of the areas of applications include the HVAC systems, the cleaning process especially by the use of sensors, transfer of heat among other applications. The applications of the devices have gained importance due to the evolution of technology.
Pointer, W. D., Delchini, M. O. G., Popov, E. L., Menicovich, D., & Amitay, M. (2018). High Performance Computational Models of Synthetic Jet Actuators for Step Change Improvements in Freight Efficiency (No. ORNL/TM-2018/951). Oak Ridge National Lab.(ORNL), Oak Ridge, TN (United States). Available at: https://info.ornl.gov/sites/publications/Files/Pub115004.pdf
Jeyalingam, J. (2018). Towards the noise reduction of synthetic jet actuators using lobed orifices (Doctoral dissertation, Brunel University London). Available at: https://bura.brunel.ac.uk/bitstream/2438/17118/1/FulltextThesis.pdf
MDPI. (2020). Actuators. Available at: https://www.mdpi.com/journal/actuators/special_issues/synthetic_jet
ATS (2011). How to use Synthetic Jets for Local Thermal Management. Available at: https://www.qats.com/cms/2011/06/22/how-to-use-synthetic-jets-for-local-thermal-management/
Dahalan, M. N., Mansor, S., & Ali, A. (2012). Cavity effect of synthetic jet actuators based on piezoelectric diaphragm. In Applied Mechanics and Materials (Vol. 225, pp. 85-90). Trans Tech Publications Ltd. Available at : https://core.ac.uk/download/pdf/42914098.pdf
Chiatto, M., Capuano, F., Coppola, G., & De Luca, L. (2017). LEM characterization of synthetic jet actuators driven by piezoelectric element: A review. Sensors, 17(6), 1216. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492309/