Body temperature control system

Abstract

The system controls the temperature of the body (6), and includes a DBD actuator (9) that can be connected to a power source to generate an ionic wind in the body, and an input temperature (T i ) and the target temperature (T ta and a control unit (8) for controlling the power supply (5) in dependence on the temperature difference (ΔT) between the electrodes (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,

Description

[Technical Field]

[0001] The present disclosure teaches techniques related to heat exchange generally, and more particularly to temperature control techniques using ionic wind generated by plasma actuators based on the dielectric barrier discharge (DBD) effect. [Background technology]

[0002] There are many applications in the field where improved thermal management is required to increase or decrease the temperature of a body. For example, in the field of electronics, the miniaturization of integrated circuits requires adequate cooling to compensate for the increase in heat. However, existing proposals are generally bulky, noisy and complex (for example, more mechanical parts and gyroscopic effects). In the field of aeronautics, another example shows the opposite situation: low temperatures during flight cause icing, a harmful phenomenon that affects the aerodynamics and the performance of the aircraft.

[0003] Among other techniques, the dielectric barrier discharge (DBD) effect can be used for heating. DBDs have been known since the 19th century and involve the generation of a non-thermal discharge at a high alternating voltage between two electrodes separated by an insulating dielectric barrier. When these electrodes are arranged asymmetrically, an ionic wind is obtained.

[0004] Actuators capable of generating the DBD effect are called DBD actuators. These are typically devices with two or more superimposed electrodes (an exposed electrode and an insulated electrode) separated by a dielectric medium. The electrodes may be made of any conductive material. When high-voltage, high-frequency AC power is applied, a plasma discharge is generated. Momentum is transferred from the plasma discharge to the surroundings through collisions of ions with neutral molecules, which induces air and body forces.

[0005] Known DBD actuators are used in fluid-related applications, but DBD actuators for transferring heat are rare and limited to heating applications.

[0006] There are other plasma generation techniques, such as corona discharge, which is also a non-thermal discharge generated by applying a high DC voltage to a sharp electrode tip.

[0007] Therefore, there is a need in the state of the art to enable DBD actuators to better control the temperature of the body so as to be able to provide improved cooling, improved heating, or alternative cooling and heating. Summary of the Invention

[0008] The present invention has been made in view of the limitations of the current state of the art and the need for appropriate thermal management. According to the independent claims, a system capable of performing surface cooling and / or heating is proposed. This system may be used in particular for anti-icing (also called deicing) and defrosting (also called anti-icing) applications. This system is capable of generating an ionic wind as a result of ionizing the air, the temperature and some properties of which may be varied depending on the specific operating conditions. The ionic wind may be used to modify, e.g., remove, the boundary layer and achieve improved convective heat transfer. Advantageously, both cooling and heating of a surface can be achieved in a single embodiment of the system with alternative functions, or in separate embodiments, where one is particularly suited for cooling and the other is particularly suited for heating.

[0009] The system includes a DBD actuator, positioned near a body to be thermally conditioned, to generate an ionic wind. The DBD actuator includes electrodes and a non-gaseous dielectric material. When an electric field gradient is generated between the electrodes, a force is generated in the direction of the decreasing electric field gradient, exerting a force on the weakly ionized air on the surface of the dielectric material. As the ions are displaced, they collide with neutral air molecules, transferring momentum and generating an airflow from the collisions. This airflow is called an ionic wind. The velocity and volume of this ionic wind increase with voltage and frequency, among other parameters. The ionic wind can change boundary layer properties and flow structure.

[0010] The present invention provides a system for controlling the temperature of a body. The system includes a DBD actuator connectable to a power source and configured to generate an ionic wind at the body; and a DBD actuator for selecting an initial configuration and determining an input temperature (T) at the body. i ) and target temperature (T ta and a control unit configured to control the power supply depending on a temperature difference (ΔT) between the electrodes (i.e., the number of electrodes, the shape and geometry of the electrodes, the relative position between the electrodes (d), the dielectric material, the dielectric thickness (e), and the following setting parameters to be set: a frequency value (f), an amplitude value (V), a waveform signal, and a duty cycle. The control unit is further configured to adjust the initial configuration by changing any of the setting parameters to control the heat transferred to the generated ionic wind.

[0011] Some embodiments of the system may be defined according to the dependent claims. Among others, different DBD actuators may be used, for example, having various characteristics, such as the number of electrodes, the shape of the electrodes (i.e., flat, wavy, circular, or cylindrical), the position (i.e., edge distance, parallel, flush, etc.), the geometry (toothed, linear, pointed, etc.), the seal (absent, uniform, variable), the structure of its components (rigid, flexible), etc. These are constructional characteristics related to the manufacturing configuration of the DBD actuator.

[0012] Similarly, the characteristics of the voltage signal applied to the electrodes of the DBD actuators of the system can change the overall behavior, thereby altering the ionic wind. These characteristics include, for example, frequency, amplitude, waveform, and duty cycle. These are considered configuration parameters that can be easily changed as needed. For this purpose, a control unit is proposed that is configured to allow the power supply configuration to be changed depending on the application. The configuration parameters of the power supply DBD actuators can be taken into account when controlling the power supply.

[0013] For example, to generate a certain amount of cooling or heating to the body, the control unit may set a particular waveform, voltage, and / or frequency on the power supply and monitor whether the result has been achieved or if adjustment of the settings is otherwise necessary. The selection of parameters affects the temperature, velocity, and / or volume of the ionic wind generated by the DBD actuator by increasing or decreasing it. It also affects the boundary layer.

[0014] The performance of the system is determined by the input temperature (T i ) and the target temperature (T ta ) Even though they are fixable, both may be changed. In fact, T ta is a value set by design and may be changed by the user. i may be modified, for example, by forcing flow from different areas of the DBD system that are hotter or colder, or by a heating / cooling system installed at the DBD inlet. It may also be estimated and manually introduced. ta It should be noted that may be chosen to be unreachable, in which case the system is forced to function in only one direction (heating only, or cooling only).

[0015] In some applications, the system may take advantage of the presence of a sensor in the system that measures any parameter of interest in real time (e.g., a sensor that identifies the presence of ice). This parameter may be used to further adapt the control of the system. In a preferred embodiment, this sensor is a temperature sensor that measures the temperature of the body.

[0016] As important to achieving cooling or heating, the present invention addresses complex tradeoffs and balances of features. There are features that have opposing effects, such as configuration or setting parameters. Additionally, there are features that can alter behavior in opposite directions when changed.

[0017] For example, the greater the separation between the electrodes, the larger the discharge area, but the smaller the plasma area and the weaker the formation of the ion wind. On the other hand, if the electrodes are spaced apart, the discharge becomes non-uniform, resulting in less repeatable behavior. To compensate for the non-uniformity of the discharge, the shape of the electrode edge (which is usually straight) can be changed. For example, it is proposed that the edge be serrated or pointed. In other words, by selecting an appropriate edge shape, the discharge can be caused to start from a specific area of ​​the electrode. As a result, the discharge becomes more uniform, and as a result, the strength of the electric field increases. In this case, the edge shape compensates for the effect of the separation of the two electrodes.

[0018] Similarly, the control unit can dynamically change the power supply settings via certain configuration parameters to quickly affect the operation of the DBD.

[0019] The control unit influences how the ionic wind is generated to achieve the intended application. For example, the parameters of the voltage signal supplied to the DBD actuator are key, namely waveform, duty cycle, amplitude, and frequency. As a result, thermal conditioning of the body can be achieved. The generation of ionic wind impinging on the body surface can be varied to obtain different thermal conditioning (cooling and / or heating).

[0020] The robustness of the system may be enhanced, for example, by preventing dielectric breakdown due to excessive heating of the DBD actuator. If the temperature sensor indicates a value greater than a safety threshold (e.g., a temperature limit), the control unit reduces the excitation frequency while maintaining the voltage amplitude, thereby reducing the temperature.

[0021] This system saves energy consumption of the power supply, for example it can operate to cool the body at a lower frequency (for example below 1 kHz).

[0022] This system offers several additional advantages, namely low weight, reduced volume occupation (no heat sink or fan required for cooling applications), flexibility to adapt to specific shapes, low maintenance, and combined functionality (cooling and heating).

[0023] Furthermore, the teachings of the present invention allow for reduced complexity and improved integration of thermal protection systems applicable to disparate technologies. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic block diagram of elements of an embodiment of a system. [Figure 2] FIG. 2 is a schematic block diagram of a control unit of an embodiment of the system. [Figure 3] 10 is an exemplary flow diagram of a control unit for cooling or heating a body of an embodiment of the system. [Figure 4] FIG. 1 is a schematic diagram illustrating an embodiment of a system including a DBD actuator. [Figure 5A] Three different shapes of exposed electrodes of the DBD actuator are shown. [Figure 5B] Three different shapes of exposed electrodes of the DBD actuator are shown. [Figure 5C] Three different shapes of exposed electrodes of the DBD actuator are shown. [Figure 6A] 1 shows a DBD actuator with an unencapsulated bottom electrode. [Figure 6B] 1 shows a DBD actuator with a bottom sealing electrode. [Figure 7] Experimental results of ionic wind velocity variation with height across the DBD actuator in Figure 6B are shown for three voltage frequencies. [Figure 8A] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8B] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8C]10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8D] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8E] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8F] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 8G] 10A-10C illustrate different structural embodiments of DBD actuators for the system. [Figure 9] Different waveforms are shown. [Figure 10] Stationary and non-stationary waveforms are shown. [Figure 11] A single pulse waveform generated in the power supply is shown. [Figure 12A] 8B shows a temperature / time curve for heating an embodiment of the system of FIG. 8A. [Figure 12B] 8B shows a temperature / distance curve for heating of an embodiment of the system of FIG. 8A. [Figure 13A] 1 shows the cooling effect as a function of time and excitation frequency voltage. [Figure 13B] 1 shows the cooling effect as a function of time and voltage amplitude. DETAILED DESCRIPTION OF THE INVENTION

[0025] For a better understanding of certain aspects and embodiments of the present invention, reference will now be made to the drawings.

[0026] FIG. 1 illustrates a simplified block diagram of an embodiment of the present invention. A temperature sensor 7 measures the temperature of the body 6 and provides the measured value to a control unit 8. A power supply 5 supplies an AC voltage to a DBD actuator 9. The control unit 8 controls the power supply 5 depending on the temperature of the body 6 and a target temperature. The control unit 8 may select a specific setting for the power supply 5 as an initial configuration. Cooling or heating may be applied depending on the current temperature of the body 6 provided by the temperature sensor 7 and the target temperature. The initial configuration may also take into account the configuration characteristics of the DBD actuator. The electrodes of the DBD actuator form a plasma region that induces an ion wind toward the body 6. The control unit 8 thus cools or heats the body 6 by changing configuration parameters such as the voltage frequency, voltage amplitude, waveform, and / or duty cycle. The control unit 8 checks after a time interval Δt whether the body temperature has changed as desired using the temperature sensor 7. If the check reveals that the body temperature has not changed sufficiently, the initial configuration may be adjusted to facilitate reaching the target temperature.

[0027] The control unit may be activated to operate in a heating mode or a cooling mode based on the temperature sensor and a target temperature. Additionally, the control unit may include other input signals to change its method of operation. Additionally, the control unit may allow operation in a manual mode to select between two settings (cooling or heating).

[0028] In heating mode, the default waveform is nanopulse (ns-DBD). If the target temperature cannot be reached with the preset configuration, the excitation voltage is increased, followed by an increase in frequency. These may be alternated or simultaneous, for example. If the target temperature is reached, a less power-consuming waveform may be introduced, either in a duty cycled, non-stationary wave, or in bursts.

[0029] In cooling mode, the preset waveform is preferably a sinusoidal AC signal. If the target temperature is not reached under the preset conditions, the excitation voltage is increased. It should be noted that while increasing the excitation voltage to achieve surface cooling, undesirable effects may occur, such as an increase in temperature. In such a situation, the excitation frequency is reduced or excitation is performed with a non-stationary wave via the duty cycle. The control unit may use similar operations to reduce power consumption when the target temperature is reached.

[0030] It should be noted that the system shown in Figure 1 is valid even without the temperature sensor 7. In this case, the control may be pre-fixed or may be managed manually.

[0031] 2 is another block diagram of the control unit 8. The control unit 8 can appropriately adjust the initial configuration, e.g., the setting parameters of the power supply 5, taking into account the initial configuration having the setting parameters of the power supply 5 and the configuration parameters of the DBD actuator 9. The configuration parameters of the DBD actuator 9 may be part of the input of the control unit 8 (e.g., limit amplitude of the voltage in a certain frequency range (amplitude limit), limit frequency of the voltage signal in a certain amplitude range (frequency limit), and also safe operating values ​​such as limit temperature of the DBD actuator).

[0032] The control unit 8 is configured to monitor the safe operation of the DBD actuator 9 by checking whether a change in the configuration parameters of the power supply 5 has caused a limit operating value of the DBD actuator 9 to be reached, where the limit operating value has been selected according to the remaining configuration parameters in the power supply 5.

[0033] FIG. 3 is a flow diagram showing the implementation of the control unit 8 for temperature control. b ) but T ta below (heating) or T taIf the temperature of the body is above 100°C (cooled), the initial configuration is used to activate the power supplies and generate a plasma using the DBD actuators. After a time Δt, the temperature of the body reaches the desired target temperature T ta Compared to T b and T ta If there is a temperature difference between the power supply and the cooling system, the control unit can adjust the initial configuration by changing the setting parameters of the power unit. In this way, the setting parameters may be selectively changed for cooling or heating.

[0034] FIG. 4 is a schematic diagram of an embodiment of a system 10 for altering the temperature of a body 6 based on the dielectric barrier discharge (DBD) effect. The system 10 includes a DBD actuator with two electrodes. The first electrode 1 has a side exposed to the outside (generally, the surrounding air, but also other fluids). The second electrode 2 has a sealing structure 4 to avoid undesired effects and reduce power consumption. Both electrodes are connected to a power supply 5 that supplies a high AC voltage. As described below, other DBD actuators may be suitable. Preferably, the voltage waveform and related parameters may be defined depending on the intended use. Some of the parameters to be set, such as frequency, amplitude, waveform, and duty cycle, are described below. As can be seen, electrodes 1 and 2 are arranged in parallel planes, defining a space between them for a dielectric layer 3 of a specific thickness "e." Electrodes 1 and 2 are not vertically aligned, and there is an offset "d" between their edges 1b and 2b. When a high voltage is applied, this causes ionization of the air, generating an ionic wind, indicated by the arrow, that can be utilized for several purposes. In particular, for the purpose of cooling or heating the surface of body 6. It should be noted that d>0 means a gap or separation between the electrodes, i.e., a gap from edge 2b to edge 1b, while d<0 means at least a partial overlap between both electrodes, i.e., edge 2b is below electrode 1. As a general rule, configurations with d<0 will be preferred for heating applications, while configurations with d>0 will be preferred for cooling applications.

[0035] Figures 5A-5C show three different shapes of exposed electrodes. The geometric characteristics may vary. Figure 5A shows an electrode with a straight edge. Figure 5B shows an electrode with triangular teeth. Figure 5C shows an electrode with a sinusoidal edge. The shape of the edge is important for generating a proper discharge, as will be explained below.

[0036] The thickness of the electrode has not been found to be a key factor, but the smaller the thickness the better. Generally, the electrode thickness should be less than 200 μm, and preferably about 50 μm.

[0037] FIG. 6A shows a simplified DBD actuator, defined by two asymmetrically positioned electrodes 1 and 2 located on opposite sides of a dielectric material 3 (dielectric medium 3). In this embodiment, there are no encapsulated electrodes. An AC high voltage source 5 applies a voltage to electrodes 1 and 2. In the context of this specification, high voltage is understood to be 5 kVpp to 50 kVpp. When a voltage threshold is exceeded, a discharge occurs, ionizing the air on both sides of the dielectric, in the region where the electric field is strongest. Plasmas are formed on both sides of the dielectric material 3. This results in opposing ion winds on both sides.

[0038] FIG. 6B shows another simplified DBD actuator. In this case, plasma generation occurs only on one side of the dielectric 3. To prevent plasma generation on the other side of the dielectric, one of the electrodes is isolated, for example, by making it a sealed electrode. A region of plasma forms on the exposed electrode. Typically, the electrode connected to ground is usually the sealed electrode.

[0039] The plasma region is formed by a strong electric field generated by applying a high voltage signal to the electrodes. Ionized air contained in the plasma region propagates from the edge 1b of the exposed electrode 1 to the sealed electrode 2, generating an ionic wind.

[0040] The dielectric material prevents the formation of an electric arc between the two electrodes. Furthermore, if a charge builds up in the dielectric material 3, the discharge will decrease and eventually disappear. For this reason, an AC voltage signal is usually used.

[0041] Figure 7 shows experimental measurements of the velocity of the induced ionic wind as a function of height h from the DBD actuator surface depicted in Figure 6B. Kapton® was used as the dielectric element. A power supply voltage of 14 kVpp (7 kV amplitude) was used, with three different frequency values ​​(1 kHz, 2 kHz, and 3 kHz) at a position L = 16 mm from the trailing edge 1b of the exposed electrode. It can be seen that the higher the frequency, the faster the ionic wind velocity. This fact is exploited by the control unit to modify the function of the DBD actuator. The velocity reaches a maximum near the actuator surface, between heights of 0.5 and 1 mm.

[0042] 8A-8G show schematic diagrams of different formations of electric wind (ionic wind) according to various system embodiments of DBD9, where the DBD actuators of electrodes have various configuration parameters (placement, size, number, etc.). The direction of the arrow indicates the direction of the ionic wind. The size of the arrow is independent of the magnitude of the velocity.

[0043] Figure 8A shows the case where an exposed electrode 1 is placed on top of a dielectric layer 3. A sealed electrode 2 is placed on the opposite side of the dielectric layer. Both electrodes 1 and 2 are layered (e.g., foil tape), arranged in parallel planes, and have displacements at their edges. A plasma is generated at the edge of exposed electrode 1 closest to sealed electrode 2. Such DBD actuators may be suitable for cooling and heating applications.

[0044] Figure 8B shows the case where exposed electrode 1 is placed on top of dielectric layer 3. Enclosed electrode 2 is placed on the opposite side of the dielectric. Both electrodes 1 and 2 are layered and arranged in parallel planes. Exposed electrode 1 is smaller than and completely overlaps enclosed electrode 2. Plasma is generated at both edges of exposed electrode 1. Such DBD actuators may be better suited for heating applications.

[0045] 8C shows another embodiment where one electrode protrudes relative to the other, thereby defining an additional separation or gap (d>0). This gap between the exposed electrode 1 and the sealed electrode 2 may be modified to suit the needs. Such DBD actuators may be better suited for cooling applications.

[0046] FIG. 8D shows another embodiment with the addition of a third electrode. In this configuration, the electric wind is generated perpendicular to the surface of the body 6. For three electrodes, two electrodes are exposed and connected to the same power source. The electric wind is generated so that the wind direction can be changed by 180 degrees. To achieve this result, the voltage and / or frequency applied to electrodes 1 and 13 must be different. Two power sources may be used. Such DBD actuators may be better suited for heating applications.

[0047] Figure 8E shows another embodiment similar to the configuration described in Figure 8A, where the dielectric thickness is not constant. Portions of the sealed electrode are not parallel to the plane of the exposed electrode. By reducing the dielectric thickness in areas where the electric field strength is reduced, a larger plasma region is generated. Such DBD actuators may be better suited for cooling applications.

[0048] 8F shows another embodiment with three electrodes. In this configuration, the third electrode 13 is electrically connected to the grounded sealing electrode. When electrode 1 is connected to an AC high voltage signal and electrodes 2 and 13 are connected to ground, the discharge has the advantage that electrode 13 allows for greater charge neutralization, reducing charge buildup in the dielectric material 3. Such DBD actuators may be better suited for heating applications.

[0049] Figure 8G shows an embodiment with three electrodes, called a "sliding discharge," which combines corona and DBD discharges. There are two exposed electrodes and one sealed electrode, separated by a dielectric element 3. In this arrangement, an additional electrode 13 is connected to a negative DC power supply. Between electrodes 1 and 2 is a basic DBD. A corona discharge channel is formed from electrode 1 to electrode 13. This configuration achieves a larger plasma area at a reduced voltage. Such a DBD actuator may be better suited for heating applications.

[0050] The above configurations are merely examples. Other types may be defined. Combinations of different configurations are also possible, some of which share electrodes.

[0051] Although the figure shows a single DBD actuator 9, the system may include multiple actuators acting on the same or different bodies. It should be noted that the electrode geometry is not limited to being flat, layered, or parallel between the electrodes. Indeed, adapting the DBD and its components to the body and its specific geometry can foresee performance benefits for the system.

[0052] Other configuration parameters that affect the performance of this embodiment are discussed below.

[0053] The thickness of the exposed electrode relatively affects the strength of the electric field. The width and material of which the electrode is made are not so important. The thinner the exposed electrode, the better the results in terms of generating ionic wind.

[0054] The width of the sealing electrode increases the length of the plasma region and improves performance, but beyond a certain value no further improvement is obtained.

[0055] The arrangement of the opposing electrodes may be such that there is an offset "d" between the edges that are arranged in front of each other. The offset "d" may therefore be positive or negative. The best results for ionic wind generation are obtained with an offset of -1 mm to 1 mm. An overlapping electrode configuration is associated with a more uniform discharge. This embodiment also allows for a small increase in performance.

[0056] The material of the dielectric layer is very important and affects the performance of the DBD system and its maximum operating conditions. Typical materials used as dielectrics include Teflon, quartz, Kapton, Macor, Bakelite, quartz, Delrin, methacrylate, polycarbonate, etc. In reality, no dielectric is perfect. Which dielectric is most appropriate depends on the specific application.

[0057] Apart from the previous considerations, electrical excitation is also very important in the behavior of the system.

[0058] Figure 9 shows several types of electrical signals that can be used to supply the system: sine wave, square wave, triangular wave, sawtooth wave, and pulse wave. Generally, sine waves are preferred for cooling applications, and very short duration pulse waves are preferred for heating applications.

[0059] Transient excitation can be achieved by modulating the voltage signal using pulses, e.g., by turning an AC signal on and off at a constant frequency. The duty cycle is determined by the relationship between the operating time and the excitation period. Steady-state operation has a 100% duty cycle. Transient operation excites instabilities in the separated boundary layer and can produce better results than steady-state operation.

[0060] Figure 10 shows steady and unsteady waveforms. This type of excitation is effective for both cooling and heating. In terms of frequency, nanosecond pulsed discharges are more efficient than microsecond discharges. The power supply must be capable of delivering such short duration signals.

[0061] Nanosecond pulsed discharges, also referred to as ns-DBDs, have been shown to be effective for flow control applications over a wide Mach range. They also have a significant effect on heat transfer, allowing for rapid heating. Configurations based on nanosecond pulsed discharges are essentially the same as conventional DBDs, which have already been described and are also referred to as AC-DBDs in this context. All described configurations are valid and applicable to both.

[0062] The Joule effect is key in the configuration of ns-DBDs. The air surrounding the system heats up so quickly that it generates a compression wave that propagates at the speed of sound. In ns-DBD systems, excitation is generated by high-voltage pulses (5 to 50 kV) with rise times on the order of tens of nanoseconds and durations of 5 ns to 200 ns, as can be seen in Figure 11.

[0063] Figure 11 shows a typical form of a single pulse repeated at a certain frequency. These pulses are used in the so-called ns-DBD configuration. The application of the ns-DBD configuration is as an anti-icing element due to its high ability to emit heat to avoid ice formation on airplanes.

[0064] Figures 12A and 12B show experimental results for heating. Figure 12A shows the temperature change over time for an embodiment of the system configured as in Figure 8A. Similarly, Figure 12B shows the temperature change along a line parallel to edge 1b and located 5 mm from this edge. A rise of approximately 100°C can be achieved in about 20 seconds. The specific settings used were a frequency of 1500 Hz, an amplitude of 16 kV, and a nanosecond pulse waveform. Higher frequencies may yield better results.

[0065] Increased voltage and frequency means increased heating capacity in the antifreeze or defrost system. Alternatively or additionally, increased heating area may be achieved by the "sliding discharge" configuration of Figure 8G.

[0066] When increasing the voltage or frequency in order to generate more ionic wind in terms of cooling capacity, care must be taken to ensure the desired results are achieved. The temperature of the wind itself also increases. This increase in temperature may negate the desired improvement. Furthermore, as will be seen in the figures below, it may have the opposite effect. This effect is taken into account by the control unit, which will then appropriately control the power supply to avoid any adverse effects on the intended purpose.

[0067] FIG. 13A shows the temperature change over time of a plate (which may be a body) heated to 70°C under the action of the embodiment of the system of FIG. 4. The power supply voltage is set at a fixed amplitude of 20 kVpp, while the frequency is increased. As can be seen, an increase in frequency means a greater temperature drop in the plate, and therefore an increase in cooling capacity. However, this cooling capacity decreases with increasing frequency, and the trend may even be reversed. Increasing the speed of the ionic wind can increase the temperature of the wind itself, which can cause the plate to reheat after a certain time. The control unit monitors this behavior and applies countermeasure configurations if necessary.

[0068] Figure 13B shows a similar behavior in a graph with several curves representing temperature change over time for a fixed frequency of 1 kHz. Each curve corresponds to a voltage amplitude. It can be seen that with each increase in voltage, the cooling improves slightly, but then cancels out and reverses once the voltage exceeds 22 kVpp.

[0069] The curves in Figures 13A and 13B suggest that DBD cooling is possible at the expense of limited performance and high power consumption. This problem is addressed by performing a rather opposite series of actions.

[0070] [Example] The present invention will be specifically described below with reference to several examples, but these are not intended to limit the present invention.

[0071] A control unit provides dynamic control of the power supply settings.

[0072] [Cooling setting parameters] The lowest possible frequency shall be set. DBD actuators operate in the range of 1 kHz to 50 kHz under normal conditions. Advantageously, the system allows the operating frequency to be reduced by at least one or two orders of magnitude, with the optimum range being below 100 Hz. At such low frequencies, the ionic wind has little cooling capacity. For this reason, the excitation voltage is increased by the control unit to a value of the order of 25 kVpp.

[0073] There are also some recommendations regarding the configuration parameters. Firstly, the exposed electrode and the sealed electrode should be separated, which leads to a smaller plasma region and a weaker ion wind. However, the distance between the electrodes leads to a non-uniform discharge, i.e. the discharge does not exhibit repeatable behavior.

[0074] Second, to compensate for the non-uniformity of the discharge, the exposed electrode, which is usually straight as shown in Figure 5A, is replaced with a sawtooth electrode as shown in Figure 5B, so that the discharge always starts from the tooth of the electrode. The discharge becomes more uniform and the electric field becomes stronger, which compensates for the disadvantage of separating the two electrodes and increases the parameter d.

[0075] With this construction and operation, ionic wind is achieved with minimal temperature rise, thus providing excellent cooling with minimal power consumption.

[0076] In summary, to achieve good cooling capacity, certain approaches are taken that deviate from the normal operation of DBD actuators: different frequency ranges are used, separation distances between the electrodes are required, and specific geometries are required to control the discharge.

[0077] [Example of cooling operation] As input, let's say the body temperature is 70°C and the target temperature is 40°C. When the ambient temperature is around 25°C, some conditions and constraints come into play: the higher the ambient temperature, the less heat flow will be dissipated from the body surface. On the other hand, a lower ambient temperature will result in a lower body temperature being reached.

[0078] Configuration parameters: Thickness is on the order of 0.5mm (Kapton material). The separation d between the electrodes is greater than 0 mm, preferably 3 mm (and may be between 0 and 8 mm).

[0079] Configuration parameters: i.Vpp<40kVpp ii.f>50Hz iii. Waveform: AC (sine wave, square wave, etc.) iv. Possibility of duty cycle operation to reduce power consumption

[0080] If the dielectric thickness is large, the separation distance d can be reduced to 0 mm. i.Vpp>12kVpp ii.f>500Hz iii. Waveform: AC (sine wave, square wave, etc.) iv. Possibility of operating in cycles to reduce power consumption

[0081] (Preferably, the maximum cooling frequency limit may be in the range of 10 Hz to 5 kHz, and the minimum cooling amplitude limit may be in the range of 5 kVpp to 40 kVpp, and more preferably, the maximum cooling frequency limit may be in the range of 10 Hz to 100 Hz.)

[0082] [Heating setting parameters] The voltage frequency and amplitude shall be set as high as possible. The control unit shall operate with a safety margin to avoid exceeding the temperature of the dielectric used and dielectric breakdown. DBD actuators shall operate in the range of a few kHz and tens of kV in normal operation.

[0083] [Example of heating operation] As input, suppose the body temperature is -10°C and the target temperature is 10°C. If the ambient temperature is the same as or lower than the body temperature, a higher energy input is required.

[0084] Configuration parameters: The type and thickness of dielectric used will depend on the space available in the application: Kapton® with a thickness of 0.5 mm allows the electrodes to overlap from negative d to 0 mm.

[0085] Configuration parameters: iV>10kV ii.f>2kHz iii. Waveform: preferably nanopulse

[0086] These and other features, functions, and advantages described above may be achieved independently in various embodiments or may be combined in yet other embodiments.

Claims

1. A system for controlling the temperature of a body, comprising: a DBD actuator connectable to a power source and configured to generate an ionic wind at the body; a control unit configured to control the power supply in dependence on a temperature difference between an input temperature and a target temperature at the body and in dependence on an initial configuration; The initial configuration includes the following configuration parameters of the DBD actuator: number of electrodes, shape and geometry of electrodes, relative positions between electrodes, dielectric material, and dielectric thickness; The initial configuration further includes the following setting parameters for the power supply: frequency value, amplitude value, waveform signal, and duty cycle; the control unit is further configured to adjust the initial configuration by changing any of the setting parameters to control heat transferred to the generated ionic wind; the control unit is configured to apply a cooling configuration when the target temperature is lower than the temperature of the body, the cooling configuration including a frequency value less than a maximum cooling frequency limit and an amplitude value greater than a minimum cooling amplitude limit; The system, wherein when the target temperature is greater than the temperature of the body, the control unit is configured to apply a heating configuration, the heating configuration including a frequency value greater than a minimum heating frequency limit and an amplitude value less than a maximum heating amplitude limit.

2. The system of claim 1 , wherein the maximum cooling frequency limit is in the range of 10 Hz to 5 kHz and the minimum cooling amplitude limit is in the range of 5 kVpp to 40 kVpp when the target temperature is lower than the temperature of the body.

3. The system of claim 2 , wherein the maximum cooling frequency limit is in the range of 10 Hz to 100 Hz.

4. 4. The system of claim 2 or 3, wherein the separation between the edges of the electrodes is between 0 and 8 mm.

5. 5. The system of claim 2, wherein the exposed electrodes of the DBD actuator have non-straight edges, preferably a saw-tooth shape.

6. when the target temperature is higher than the temperature of the body, the DBD actuator includes a third electrode, the third electrode and the first electrode being located on the same side of the dielectric material; The system of claim 1 , wherein the third electrode is electrically connected to the first electrode, or the second electrode, or an external power source (AC or DC), or remains as a floating electrode.

7. The system of claim 6 , wherein the separation between the edges of the electrodes is negative and both electrodes partially or completely overlap.

8. 8. The system of claim 1, further comprising a sensor configured to measure a parameter of interest within the system, the control unit being provided with the measured parameter of interest as an input.

9. The system of claim 8 , wherein the sensor is a temperature sensor configured to measure a temperature of a surface of the body, and the control unit is provided with the measured temperature as an input temperature.

10. The system of claim 1 , wherein the DBD actuator includes a flexible component or is adapted to a particular shape.

11. The system of claim 1 , wherein the dielectric material in the DBD actuator has a non-constant thickness.

12. 12. The system of claim 1, comprising a plurality of DBD actuators.

13. 13. A system according to any one of claims 1 to 12, wherein the control of the system is pre-fixed or manually managed.

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