EP2297540B1 - Capacitive device and method for the electrostatic transport of dielectric and ferroelectric fluids - Google Patents

Description

The invention relates to a device and a method for conveying fluid media.

State of the art

For cooling electrical, electronic or micromechanical assemblies and integrated circuits driven by turbo or positive displacement pumps convection of liquid or gaseous fluids is widespread. The recirculated fluid absorbs the heat at the hot, small surface of the component to be cooled by means of thermal diffusion and transfers it to a heat exchanger with a large surface in the form of thin fins or ribs on the system surface, usually the well-conductive housing of the assembly. Conveniently affects media flow on the outer surface, it counteracts boundary layer effects that adversely affect the heat transfer.

The driven by pumps or blowers (forced) coolant circulation requires compared to the passive heat transfer by thermal diffusion increased design effort. In addition, electrical or mechanical drive power is absorbed and thus increases the total power loss.

Cooling of power electronic components such as output stage transistors and voltage transformers and highly integrated microcomputers and other digital circuits (ASICs) is widely used in operation at high clock rates by circulation of air or water by means of positive displacement or turbopumps (blowers), especially in the case of high local power dissipation densities and thermally unfavorable operating environments , Be beside water or air For cooling electronic control units in machinery or engine and transmission control devices of motor vehicles also fuels or oils used as heat exchange media.

The cooling of electronic engine control units in the automotive industry, for instance by means of fuel circulation, places high, costly demands on the durability and permanent tightness of the pipelines, pumps, valves and heat exchangers. Even the escape of small amounts of fuel from the cooling circuit usually leads to the failure of the electronics.

Also known is the passive fluid circulation according to the principle of self-sustaining convection, especially the widespread in the field of computer electronics "heat pipe". It is a hermetic system for heat transfer by means of evaporative cooling and self-sustaining coolant convection. The boiling temperature of the fluid used is in the thermal operating range of the heat source to be cooled. The liquid phase wets the inner wall of a thin tube, the gas phase can flow driven by the vapor pressure inside the tube to the heat sink and transfer the heat of vaporization there by condensation on a heat exchanger. The thickness of the liquid layer wetting the inner tube wall is limited by the capillary effect, which allows only relatively small tube diameter and thus limits the heat flow cross section of the heat pipe.

Furthermore, the electric cooling by means of Peltier elements based on the thermoelectric Peltier effect is known. Such elements consist of two interconnected semiconductors whose conduction band lower edges are at different energy levels. If an electrical voltage is present across the boundary layer between the semiconductors, so that an electric current flows from the semiconductor with the energetically higher conduction band edge (heat source) to the semiconductor with the energetically lower conduction band edge (heat sink), a heat flow from the heat source also comes with the electrical conduction current sinking. The electrons that pass from the heat source into the heat sink transmit a part of their in the. By relaxation to the lower conduction band lower edge Heat source absorbed thermal excitation energy on the crystal lattice of the heat sink.

This thermoelectrically induced heat flow counteracts the heat diffusion, in addition, unavoidable ohmic losses heat the semiconducting materials. The thermal efficiency of Peltier elements is therefore low in relation to other known cooling mechanisms. In addition, they may take up more space than the electronic components to be cooled themselves. Peltier elements are also relatively expensive and are therefore generally not suitable for widespread use.

The publication US 4,396,055 A relates to an apparatus according to the preamble of claim 10 for conveying a dielectric fluid in a heat pipe along a flow path.

Disclosure of the invention

According to the invention, an apparatus according to claim 10 and a method according to claim 1 are provided for conveying at least one heat exchange medium having at least a first fluid having a first permittivity and at least a second fluid having a second permittivity different from the permittivity of the first fluid wherein the first fluid in the liquid phase does not mix with the second fluid in the liquid phase, whereby at least one dielectric interface is established between the first and second fluids. The at least two fluids of different permittivity thus form a layered dielectric and may consist of homogeneous substances or substance mixtures or be composed of inhomogeneous mixtures such as emulsions or suspensions.

The device according to the invention comprises a capacitive arrangement which has at least two adjacent electrodes, in whose interspaces at least one flow channel extends, in which the at least one heat exchange medium flows. According to the invention, each electrode is provided with exactly one electrical voltage source of a voltage control device or with exactly one electric charge source of a charge control device each electrode can be charged and discharged independently of the other electrodes.

Furthermore, the excitation of at least one electric field is provided by means of the electrode arrangement according to the invention in at least one flow channel, wherein the field is excited in the heat exchange medium in particular in the environments of dielectric interfaces of at least two fluids of different permittivity.

The electric field induces feed forces in the environments of the dielectric interfaces which act in the direction of increasing the capacitance of the field-exciting electrodes. The fluid portions of higher permittivity seek into the field-filled interstices of the electrodes and displace the fluid portions of lower permittivity whereby the heat exchange medium advances in the direction of advancing forces due to cohesive forces in the fluids as a whole. This effect is achieved both with the voltage and charge of the field-conducting electrodes being fixed and is independent of the local orientation of the electric field vector, since the molecular dipole moments of dielectric fluids and ferroelectric colloids are preferably parallel to the local electric field apart from thermal fluctuations (orientation polarization) ).

Furthermore, according to a development of the invention, a method for determining the capacitance of field-exciting electrodes (capacitance matrix) and furthermore for determining the position of dielectric interfaces between fluids of different permittivity is provided. At the terminals of the electrode assembly, a capacitive measuring device is connected, such as a capacitive measuring bridge. The movement of a dielectric interface due to the electric feed field changes the capacitance of those field-exciting electrodes, in the influence of which the dielectric interface lies. With the voltage control device, the voltages applied to the field-exciting electrodes are varied. If this changes the capacitance of the electrodes, then there is a dielectric interface in the electrode gap. On the other hand, if the capacitance of the electrodes does not change, then the flow channel section in the electrode interstice is homogeneously filled with a single fluid. In this way, the position of all dielectric interfaces is detected. The capacity (capacitance matrix) of the field-exciting electrodes with a homogeneous and layered dielectric can be found empirically or by numerical methods, in the case of a simple or symmetrical electrode geometry as in the case of a plate capacitor or circular cylindrical capacitor also be known analytically.

According to the invention, it is further provided that the method by means of progressive, voltage or charge controlled charging and discharging of the electrode assembly according to the invention causes a propagating in the advancing direction excitation of an electric field in at least one flow channel of the at least one heat exchange medium, in particular in areas of dielectric interfaces between the at least two Fluids of different permittivity contained in the heat exchange medium. In each of the advancing steps, the electrode assembly maintains an electrical field excitation leading the dielectric interfaces in the advancing direction until the advancing forces have decayed and the capacitance of the field-exciting electrodes no longer increases. According to the invention, the charges are now transferred with the voltage or charge control device to the adjacent electrodes in the feed direction, which may be connected in parallel to increase their capacity, and carried out the next feed step.

According to the invention, the feed method by means of a voltage or charge control device progressively charges only those electrodes in whose interstices dielectric interfaces are found with the above-described method for determining the capacitance. Thus, the electrical field excitation is energetically favorable limited to the environments of the interfaces, since only there act feed forces on the heat exchange medium. The electric feed field is locally energized and maintained until the capacitance of the field-exciting electrodes no longer increases and the affected dielectric interface no longer progresses, thus ending the feed step.

According to a development of the method according to the invention, the feed steps with temporarily held voltages to the Electrode terminals or temporarily held charges carried on the electrodes.

According to a development of the invention, the voltage or charge control device superimposed on the progressively excited electric feed field a static electric field, which counteracts the escape of the dielectric fluids contained in the heat exchange medium from the device according to the invention, if the permittivity of the medium surrounding the device according to the invention is less than the permittivity the fluids in the heat exchange medium.

According to a development of the invention, at least one of the fluids of the heat exchange medium consists of a homogeneous ferroelectric substance, in particular a ferroelectric liquid crystal, or of a suspension or emulsion containing ferroelectric colloids.

According to a development of the invention, the heat exchange medium has at least one first fluid section, which consists of the liquid phase of a dielectric fluid, and at least one further fluid section, which consists of the vapor phase of this first fluid.

According to a development of the invention, the boiling temperature of at least one of the fluids contained in the heat exchange medium is in the thermal operating range of the at least one heat source to be cooled or the at least one heat sink to be heated.

According to a development of the invention, a method is provided for determining the flow velocity of at least one dielectric interface between fluid sections of different permittivity, wherein the temporal change of the capacitance of field-exciting electrodes, in the interspace of which is a flowing with the heat exchange medium dielectric interface is determined.

According to a development of the invention, starting from the method for determining the flow velocity, a method is provided which by means of temporal correlation of the capacitance variation of different electrodes, in whose interspaces dielectric interfaces between fluid sections of different permittivity have penetrated, the length of homogeneous fluid sections is determined.

According to a development of the invention, starting from the method for determining the electrode capacitance and determining the position of dielectric interfaces between fluid sections of different permittivity, a method for determining the fluid density and fluid temperature is provided. Herein, according to the method described above, those field-exciting electrodes are found whose interspace fills a homogeneous fluid section of the heat exchange medium. With homogeneous dielectric filling, the measured capacitance depends only on the temperature-dependent dielectric orientation polarization of the fluid. The relationship between temperature and polarization in fluids with permanent molecular dipole moment, such as water, is known by the Debye equation, for those with induced dipole moment by the Clausius-Mossotti equation. According to the invention, the functional relationship between the measured capacitance of the electrodes and the dielectric polarization and temperature of the dielectric fluid is shown as a numerical algorithm in the program of a microcomputer.

According to the invention, the numerical algorithm in the program sequence of this computer determines the heat flow through the field-generating electrode arrangement from the measured capacitance and the temperature of the homogeneous fluid section enclosed by the electrodes together with the flow velocity determined according to the invention and the known specific heat capacity of the fluid.

The embodiments of the device according to the invention are particularly suitable for electrostatic convection drive dielectric and ferroelectric fluids and are advantageous for use in convection circuits for cooling or heating of electrical, electronic or micromechanical assemblies in engine and transmission control units of Motor vehicles and machinery that must meet high standards of robustness, maintenance and durability.

Furthermore, the embodiments of the device according to the invention are suitable for use in mobile, electronic terminals such as laptops, PDAs, etc., whose batteries have low charge capacity and do not allow a power-consuming, electrically driven Kühlungskonvektion using pumps or blowers. Furthermore, the invention is suitable as an additional drive for circulating the liquid phase of the heat exchange medium in a heat pipe (heat pipe) with self-sustaining convection.

The electrodes and flow channels of the device according to the invention are suitable in miniaturized form for embedding in multilayer electronic printed circuit boards or ceramic substrates; the electrodes may be interconnected with the electronic assemblies and used as capacitors of variable capacitance in the microelectronic or mechanical assemblies to be cooled or heated.

Embodiments of the invention with a one-piece outer electrode, which is designed as a closed outer wall of the flow channel, are completely shielded electromagnetically. The signal integrity of electronic components and interconnects is not affected, there is no electromagnetic interference at the electrodes during the transient excitation of the electric feed field.

Brief description of the pictures

Abbildung 1

Schnittansicht einer ersten Ausführungsform der erfindungsgemäßen Vorrichtung,

Abbildung 2

erste Ausführungsform, der eine elektrische Spannungs- oder Ladungssteuerungsvorrichtung zugeordnet ist,

Abbildung 3

erste Ausführungsform in einem ersten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenspannung,

Abbildung 4

erste Ausführungsform in einem zweiten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenspannung,

Abbildung 5

erste Ausführungsform in einem dritten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenspannung,

Abbildung 6

erste Ausführungsform in einem ersten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenladung,

Abbildung 7

erste Ausführungsform in einem zweiten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenladung,

Abbildung 8

erste Ausführungsform in einem dritten Vorschubschritt einer ersten Durchführungsart des Verfahrens bei festgehaltener Elektrodenladung,

Abbildung 9

zweite Ausführungsform der erfindungsgemäßen Vorrichtung mit einteiliger Innenelektrode,

Abbildung 10

dritte Ausführungsform mit einer eingebetteten ersten Ausführungsform und zwei getrennten Strömungskanälen,

Abbildung 11

vierte Ausführungsform in Verbindung mit einem Wärmeleitrohr (heat pipe),

Abbildung 12

fünfte Ausführungsform in Verbindung mit elektrischen Spannungs- oder Ladungsquellen,

Abbildung 13

sechste Ausführungsform in Verbindung mit elektrischen Spannungs- oder Ladungsquellen,

Abbildung 14

siebte Ausführungsform ohne Innenelektroden in Verbindung mit elektrischen Spannungs- oder Ladungsquellen,

Abbildung 15

achte Ausführungsform ohne Innenelektroden mit versetzten Außenelektroden in Verbindung mit elektrischen Spannungs- oder Ladungsquellen,

Abbildung 16

achte Ausführungsform in einem ersten Vorschubschritt und Zustand der elektrischen Felderregung einer zweiten Durchführungsart des Verfahrens,

Abbildung 17

achte Ausführungsform in einem zweiten Vorschubschritt und Zustand der elektrischen Felderregung einer zweiten Durchführungsart des Verfahrens,

Abbildung 18

achte Ausführungsform in einem dritten Vorschubschritt und Zustand der elektrischen Felderregung einer zweiten Durchführungsart des Verfahrens,

Abbildung 19

achte Ausführungsform in einem vierten Vorschubschritt und Zustand der elektrischen Felderregung einer zweiten Durchführungsart des Verfahrens,

Abbildung 20

achte Ausführungsform in einem ersten Vorschubschritt und Zustand der elektrischen Felderregung einer dritten Durchführungsart des Verfahrens,

Abbildung 21

achte Ausführungsform in einem zweiten Vorschubschritt und Zustand der elektrischen Felderregung einer dritten Durchführungsart des Verfahrens,

Abbildung 22

achte Ausführungsform in einem dritten Vorschubschritt und Zustand der elektrischen Felderregung einer dritten Durchführungsart des Verfahrens,

Abbildung 23

achte Ausführungsform in einem vierten Vorschubschritt und Zustand der elektrischen Felderregung einer dritten Durchführungsart des Verfahrens,

Abbildung 24

Querschnitt einer neunten Ausführungsform mit ineinandergreifenden, geschichteten Plattenelektroden und zugeordneter elektrischer Spannungsquelle und

Abbildung 25

Querschnitt einer zehnten Ausführungsform mit radial geschichteten oder gewickelten kreiszylindrischen Elektroden und zugeordneter elektrischer Spannungsquelle.

Figures 1 to 23 illustrate advantageous embodiments of the device according to the invention in a longitudinal section along the feed direction, Figures 24 and 25 in cross-section, namely:

illustration 1

Sectional view of a first embodiment of the device according to the invention,

Figure 2

first embodiment, which is associated with an electrical voltage or charge control device,

Figure 3

first embodiment in a first feed step of a first embodiment of the method with the electrode voltage held closed,

Figure 4

first embodiment in a second feed step of a first embodiment of the method with the electrode voltage held closed,

Figure 5

first embodiment in a third feed step of a first embodiment of the method with the electrode voltage held closed,

Figure 6

first embodiment in a first feed step of a first embodiment of the method with the electrode charge held,

Figure 7

first embodiment in a second feed step of a first embodiment of the method when the electrode charge is held,

Figure 8

first embodiment in a third feed step of a first embodiment of the method when the electrode charge is held,

Figure 9

second embodiment of the device according to the invention with one-piece inner electrode,

Figure 10

third embodiment with an embedded first embodiment and two separate flow channels,

Figure 11

fourth embodiment in connection with a heat pipe,

Figure 12

fifth embodiment in connection with electrical voltage or charge sources,

Figure 13

sixth embodiment in connection with electrical voltage or charge sources,

Figure 14

Seventh embodiment without internal electrodes in connection with electrical voltage or charge sources,

Figure 15

eighth embodiment without internal electrodes with staggered external electrodes in connection with electrical voltage or charge sources,

Figure 16

eighth embodiment in a first advancing step and state of electric field excitation of a second embodiment of the method,

Figure 17

eighth embodiment in a second feed step and state of the electric field excitation of a second embodiment of the method,

Figure 18

eighth embodiment in a third feed step and state of the electric field excitation of a second embodiment of the method,

Figure 19

eighth embodiment in a fourth feed step and state of the electric field excitation of a second embodiment of the method,

Figure 20

eighth embodiment in a first advancing step and state of the electric field excitation of a third embodiment of the method,

Figure 21

eighth embodiment in a second feed step and state of the electric field excitation of a third embodiment of the method,

Figure 22

eighth embodiment in a third feed step and state of the electric field excitation of a third embodiment of the method,

Figure 23

eighth embodiment in a fourth feed step and state of the electric field excitation of a third embodiment of the method,

Figure 24

Cross section of a ninth embodiment with interlocking, layered plate electrodes and associated electrical voltage source and

Figure 25

Cross-section of a tenth embodiment with radially layered or wound circular cylindrical electrodes and associated electrical voltage source.

Embodiments of the invention

Figures 1 to 23 each show sections of embodiments of the device according to the invention in longitudinal section along the feed direction of the heat exchange medium again.

illustration 1 shows a first embodiment 1 of the device according to the invention for conveying a heat exchange medium 2, the first dielectric fluid portion 3 'with a first permittivity ε ₁ , a second dielectric fluid portion 4' with a second permittivity ε ₂ and a third dielectric fluid portion 5 'with a third Permittivity ε ₃ , wherein the second permittivity ε ₂ of the third and first permittivity ε ₃ , ε _{1 is} different. The non-mixing fluids 3, 4 and 5 form dielectric interfaces 16 and thus in the flow direction of the heat exchange medium second layered dielectric. Furthermore, a one-piece, closed outer electrode 12 is provided, which is formed as an outer wall 12 'of a flow channel 6 and individual, separate inner electrodes 7, 8, 9 and 10 encloses, which are arranged along the feed direction and form a multi-part designed inner electrode 11. The outer electrode 12 and the inner electrode 11 are galvanically separated from each other. The outer electrode 12 and the inner electrodes 7, 8, 9, 10 of an electrode assembly 14 have gaps forming the flow channel 6 in which the heat exchange medium 2 flows.

According to a development of the first embodiment 1, a first plate-shaped outer electrode 12 and a second plate-shaped, separated from the outer electrode 12 outer electrode 13 are provided. Furthermore, the internal electrodes 7, 8, 9, 10 are plate-shaped and separated from the external electrodes 12 and 13. The outer electrodes 12 and 13 are designed as outer walls 12 ', 13' of the flow channel 6, which receives the heat exchange medium 2. The other outer walls of the flow channel 6 parallel to the paper plane are in the sectional view illustration 1 not shown.

Figure 2 shows the first embodiment 1, wherein it is associated with an electronic voltage control device 17, which has independently controlled electrical voltage sources U ₀ , U ₁ , U ₂ , U ₃ and U ₄ . Each of these voltage sources U ₀ , U ₁ , U ₂ , U ₃ and U ₄ is electrically connected via a single line 21 with exactly one of the internal electrodes 7, 8, 9, 10. The electrodes 7, 8, 9, 10 can be charged and discharged independently of each other. The outer electrodes 12 and 13 are electrically connected to a ground potential 18.

According to a development of the first embodiment 1, each of the internal electrodes 7, 8, 9, 10 is connected via separate individual lines 21 to exactly one of the charge sources of an electronic charge control device 20.

The electrode assembly 14 may be interconnected by means of the voltage control device 17 or the charge control device 20 to a capacitive capacitive network (capacitance matrix).

Figures 3 to 8 show successive advancing steps 24, 25, 26 of a first embodiment of the method according to the invention in the first embodiment 1 of the device with the local excitation of an electric feed field 19 by means of voltage or charge controlled charging and discharging of the field exciting electrode assembly 14. In each of Feed steps 24, 25 and 26, the local electrical field excitation 19 "remains at a fixed electrode voltages or electrode charges until a feed force 27 'has subsided on the interface 16. In the region of the dielectric interface 16 between fluid 4 with the permittivity ε ₂ and 3 fluid with the permittivity ε ₁ excites the electrode assembly 14, a local electric field 19 ', which is ahead of the interface 16 in the feed direction 27 and the force acting on the interface 16 feed force 27' causes. the fluid portion 4 'with the higher permittivity t ε _2> ε ₁ aims in the field-filled space of the electrode assembly 14 and displaces fluid 3 with the lower permittivity ε _1, whereby the heat exchange medium 2 'continues to flow due to the cohesive forces in the fluids 3, 4 in total through the flow channel 6 in the direction of the feed force 27 , Once the feed force 27 'comes to a halt, the feed step 24, 25, 26 is completed; the next step is initiated by the field excitation by means of the voltage control device 17 or the charge control device 20 on in the feed direction 27 adjacent electrodes of the assembly 14 passes.

Figures 3 to 5 show the advance of the heat exchange medium 2 in the first embodiment 1 at temporarily held, connected to the voltage control device 17 electrode voltages.

In the conveying step 24 after Figure 3 For example, the inner electrode 8 and the outer electrode 12 excite a local electric field 19 'in their space by the voltage control device 17 applying a voltage U _c between the inner electrode 8 and the outer electrode 12. The feed field 19 draws the dielectric interface 16 into the interspace of the inner electrode 8 and the outer electrode 12.

As soon as the fluid section 4 'with the higher permittivity ε ₂ fills the intermediate space of the inner electrode 8 and outer electrode 12 and the electrode capacity determined according to the invention no longer increases, the voltage control device 17 buckles in the conveying step 25 Figure 4 in addition to the voltage U _A = U _C between the electrodes 8 and 12, a voltage U _B = - U _C between the inner electrode 9 and outer electrode 12. Thus, between the inner electrodes 8 and 9, the potential difference 2 · U _C , the electric field 19 ' pulls the dielectric interface 16 into the gap of the internal electrodes 8 and 9.

As soon as the feed force 27 'fades to the area of the dielectric interface 16 and the capacity of the electrode pair 8 and 9 determined according to the invention no longer increases, the voltage control device 17 lowers in the conveying step 26 Figure 5 the voltage applied between the electrodes 8 and 12 to zero, the electric feed field 19 'is limited to the gap of the inner electrode 9 and outer electrode 12, where it exerts a feed force 27' on the heat exchange medium 2 in the vicinity of the advanced dielectric interface 16.

Depending on the applied voltage U and the capacitance C, the electrostatic energy in the field-exciting electrode arrangement 14 is. $${\mathrm{W}}_{\mathrm{e}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\mathrm{<figure-callout\; id="2"\; label="CU"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">CU</figure-callout>}}^2$$

ist größer null. Mit der Kapazitätsvariation δC = k δs entlang der infinitesimalen Wegstrecke δs ändert sich W_e gemäß $$\delta {\mathrm{W}}_{\mathrm{e}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^2\mathrm{}\delta \mathrm{C}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\delta \mathrm{s}$$

If a fluid section of higher permittivity ε ₂ > ε ₁ penetrates the distance s into the interspace of the field-exciting electrodes, then the capacitance C (s) increases, the capacitance surface area $$\mathrm{k}\left(\mathrm{s}\right):=\mathrm{dC}/\mathrm{ds}$$

is greater than zero. With the capacitance variation δC = k δs along the infinitesimal path δs, W _e changes according to $$\delta {\mathrm{W}}_{\mathrm{e}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">U</figure-callout>}}^2\mathrm{}\delta \mathrm{C}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\delta \mathrm{s}$$

entnommen. Ist F_D die auf die dielektrische Grenzfläche 16 wirkende Kraft 27 und δW_m = F_D δs die verrichtete mechanische Arbeit, so lautet die Energiebilanz W_q = W_e + W_m und daraus folgt: $$\delta {\mathrm{W}}_{\mathrm{q}}=\delta {\mathrm{W}}_e+\delta {\mathrm{W}}_{\mathrm{m}}$$

$$\begin{array}{l}\delta {\mathrm{W}}_{\mathrm{m}}=\delta {\mathrm{W}}_e=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\delta \mathrm{s}\Rightarrow \\ {\mathrm{F}}_{\mathrm{D}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\end{array}$$

Under constant voltage U, the charge quantity δQ = U δC or -δQ flows to the electrodes, the voltage source becomes the energy $$\delta {\mathrm{W}}_{\mathrm{q}}=U\delta \mathrm{Q}={\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">U</figure-callout>}}^2\mathrm{}\delta \mathrm{C}=2\mathrm{}\delta {\mathrm{W}}_{\mathrm{e}}$$

taken. If F _{D is} the force 27 acting on the dielectric interface 16 and δW _m = F _D δs is the mechanical work done, the energy balance W _q = W _e + W _m and from this follows: $$\delta {\mathrm{W}}_{\mathrm{q}}=\delta {\mathrm{W}}_e+\delta {\mathrm{W}}_{\mathrm{m}}$$

$$\begin{array}{l}\delta {\mathrm{W}}_{\mathrm{m}}=\delta {\mathrm{W}}_e=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\delta \mathrm{s}\Rightarrow \\ {\mathrm{F}}_{\mathrm{D}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.U^{2}k\end{array}$$

If the electrode arrangement is cylindrical in sections, that is to say that the cross section and capacitance in this section remain constant along the direction of flow, the capacitance coating k and therefore the force F _{D are} independent of the position of the dielectric interface 16.

Figures 6 to 8 show advancing steps of the heat exchange medium 2 under progress of the electric field excitation 19 "in the first embodiment 1 with temporarily held electrode charges applied and removed with the charge control device 20.

In the conveying step 24 after Figure 6 For example, the charge control device 20 applies the charge Qc from a charge source to the inner electrode 8, the outer electrode 12 is at ground potential 18. The electrodes 8 and 12 excite a local electric field 19 'in their space into which the interface 16 pushes. As soon as the fluid section 4 'with the higher permittivity ε ₂ fills the interspace of the inner electrode 8 and outer electrode 12 and the electrode capacity determined according to the invention no longer increases, the charge control device 20 follows in the conveying step 25 Figure 7 on the inner electrode 9, the charge -Qc on. This results in the charge difference 2 * Qc on the internal electrodes 8 and 9 and the electric field 19 'draws the dielectric interface 16 into the interspace of the electrodes 8 and 9.

As soon as the feed force 27 'decays to the surroundings of the dielectric interface 16 and the capacity of the electrode pair 8 and 9 determined according to the invention no longer increases, the charge control device 20 follows in the conveying step 26 Figure 8 the charge Qc from the inner electrode 8 from. The electric feed field 19 is thus limited to the interspace of the inner electrode 9 and outer electrode 12, where it exerts a feed force 27 'on the heat exchange medium 2 in the region of the advanced dielectric interface 16.

Depending on the charge Q, the electrostatic energy of the field exciting electrode assembly 14 $${\mathrm{W}}_{\mathrm{e}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2/\mathrm{C}$$

The capacitance variation δC = k δs with the electrode charge Q held fixed changes W _{e in} accordance with $$\delta {\mathrm{W}}_{\mathrm{e}}=-\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\left({\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2/{\mathrm{C}}^2\right)k\delta \mathrm{s}$$

No power is drawn from the voltage source when the electrode terminals are open: $$\delta {\mathrm{W}}_{\mathrm{q}}=U\delta \mathrm{Q}=0$$

Thus, the energy W _e + W _{m of} the electrode assembly 14, including the dielectric, is maintained: $$\delta {\mathrm{W}}_{\mathrm{e}}+\delta {\mathrm{W}}_{\mathrm{m}}=0\iff \delta {\mathrm{W}}_{\mathrm{m}}=-\delta {\mathrm{W}}_{\mathrm{e}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\left({\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2/{\mathrm{C}}^2\right)k\delta \mathrm{s}$$

On the dielectric interface 16, the force acts $${\mathrm{F}}_{\mathrm{D}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\left({\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2/{\mathrm{C}}^2\right)\mathrm{k}$$

worin k₀ der konstante Kapazitätsbelag des Kondensators ohne Dielektrikum ist. Der Kapazitätsbelag des axial geschichteten Zylinderkondensators ist somit unter Vernachlässigung von Rand- und Streufeldern $$\mathrm{k}=\mathrm{dC}/\mathrm{dh}={\mathrm{k}}_0\left({\epsilon }_2-{\epsilon }_1\right)$$

If the electrode assembly 14 is cylindrical along a portion of length H and h <H is the penetration depth of the dielectric interface 16, a cylindrical capacitor with a longitudinally layered dielectric and capacitance results $$\mathrm{C}\left(\mathrm{H}\right)={\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="imgf0002.png"\; state="\{\{state\}\}">k</figure-callout>}}_0\left[{\epsilon }_2\mathrm{H}+\left(\mathrm{H}-\mathrm{<figure-callout\; id="1"\; label="H\; \epsilon "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">H\; </figure-callout>},\right){\epsilon }_{}{}_1\right]={\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="imgf0002.png"\; state="\{\{state\}\}">k</figure-callout>}}_0\left[\left({\epsilon }_2-{\epsilon }_1\right)\mathrm{H}+\mathrm{<figure-callout\; id="1"\; label="H\; \epsilon "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">H\; </figure-callout>}{\epsilon }_{}{}_1\right]$$

where k _{0 is} the constant capacitance of the capacitor without dielectric. The capacity of the axially stacked cylinder capacitor is thus neglecting marginal and stray fields $$\mathrm{k}=\mathrm{dC}/\mathrm{ie}={\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="imgf0002.png"\; state="\{\{state\}\}">k</figure-callout>}}_0\left({\epsilon }_2-{\mathrm{<figure-callout\; id="1"\; label="\epsilon "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}_1\right)$$

und für die kreiszylindrische Innen- und Außenelektrode mit Radien r_A (Innenradius der Außenelektrode) und r_B (Außenradius Innenelektrode) $${\mathrm{k}}_0=2\pi {\epsilon }_0/\ln \left({\mathrm{r}}_{\mathrm{A}}/{\mathrm{r}}_{\mathrm{B}}\right).$$

The force F _D = ½ U ² k ₀ (ε ₂ -ε ₁ ) or F _D = ½ (Q / C) ² k ₀ (ε ₂ -ε ₁ ) on the dielectric interface 16 is independent when the voltage is kept in the homogeneous field from the penetration depth h <H. When charge Q is held, the force F _D decreases with increasing penetration depth h and capacity C (h). For plate electrodes of width b at a distance d $${\mathrm{k}}_{}$$$${\mathrm{}}_0={\epsilon }_0\mathrm{b}/\mathrm{<figure-callout\; id="0"\; label="d\; permittivity\; \epsilon "\; filenames="imgf0002.png"\; state="\{\{state\}\}">d\; </figure-callout>}\left(\mathrm{permittivity}{\epsilon }_{}\right)\left({}_0=8.85\cdot 10-12F/\mathrm{m}\right)$$

and for the circular cylindrical inner and outer electrodes with radii r _A (inner radius of the outer electrode) and r _B (outer radius inner electrode) $${\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="imgf0002.png"\; state="\{\{state\}\}">k</figure-callout>}}_0=2\mathrm{<figure-callout\; id="0"\; label="\pi \; \epsilon "\; filenames="imgf0002.png"\; state="\{\{state\}\}">\pi \; </figure-callout>}{\epsilon }_{}{}_0/\ln \left({\mathrm{r}}_{\mathrm{A}}/{\mathrm{r}}_{\mathrm{B}}\right),$$

Figure 9 shows a second embodiment 31 of the device according to the invention, which comprises a one-piece, in the flow direction 30 of the heat exchange medium 2 continuous inner electrode 11 and a one-piece, closed outer wall 40, which consists of an electrically insulating material. Arranged along the flow direction 30 are isolated outer electrodes 32 which are electrically separated from one another and which are embedded in or attached to the outer wall 40. The outer electrodes 32 and the inner electrode 11 are electrically separated from each other. The space between the inner electrode 11 and the flow wall 40 'formed by the outer wall 40 and the outer electrodes 32 forms the flow channel 6 of the heat exchange medium 2.

According to a development of the second embodiment 31, the outer walls 40 and an outer wall 41 are plate-shaped made of electrically insulating material, the inner electrode 11 and outer electrodes 32 are also of plate-like shape. The other lateral outer walls of the flow channel 6 are in Figure 9 not played. Technically advantageous, the outer walls 40 and 41, the inner electrode 11 and the outer electrodes 32 may be of circular or rectangular cross-section.

Figure 10 3 shows a third embodiment 33 of the device according to the invention, which is evident from the second embodiment 31 in that the first embodiment 1 replaces the inner electrode 11 of the second embodiment 31. The continuous, closed outer electrodes 12 and 13 of the embedded In Embodiment 1, in the embodiment 33, inner electrodes are opposed to the separated, separated outer electrodes 32. In addition to the inner flow channel 6 of the embedded first embodiment 1, in which the fluid sections 4 'and 5' flow, there is space between the closed outer electrodes 12 and 13 on the one hand and the outer walls 40 and 41 on the other hand, an outer flow channel 60 in which another, the fluid sections 37 'and 38' having heat exchange medium 66 is driven independently and separately from the first heat exchange medium 2. According to the invention, a first electric feed field 19 is excited in the inner flow channel 6 and a second electric feed field 19, which is independent of the first field 19, is excited in the outer flow channel 60.

Figure 11 shows a fourth embodiment 35 of the device according to the invention, which is apparent from the third embodiment 33 in that the internal electrodes 7, 8, 9 and 10 of the embedded first embodiment 1 omitted. In the interior of the one-piece, closed electrode 12 or in the space of the separate, plate-shaped electrodes 12 and 13 flows a gas phase 36 (vapor phase) of the heat exchange medium 66 of a heat pipe 34 (heat pipe). Non-mixing liquid phases 37 and 38 of the heat exchange medium 66 flow as in the third embodiment 33 through the outer flow channel 60 opposite to the flow direction 30 of the gas phase 36.

Figure 12 shows a fifth embodiment 39 of the device according to the invention, wherein the inner electrode 11 as in the first embodiment 1 and the outer electrodes 32 and the outer walls 40 and 41 as in the second embodiment 31 are made in several parts and separated. The electrodes 11 and 32 are aligned flush at their ends in the flow direction 30 and may be designed in sections as a closed tube or plate-shaped. Furthermore, each of the electrodes 11 and 32 is electrically connected to exactly one independently controllable voltage source U _A1 -U _A4 , U _{B1 -U B4} , U _{E1 -U E4 of} the voltage control device 17 or exactly one independently controllable charge source of the charge control device 20.

Figure 13 shows a sixth embodiment 43 of the device according to the invention, which is apparent from the fifth embodiment 39 in that the ends of the outer electrodes 32 and inner electrodes 11 are arranged offset in the flow direction 30.

Figure 14 shows a seventh embodiment 44 of the device according to the invention, which is apparent from the sixth embodiment 43 in that the internal electrodes 11 omitted together with the connected voltage control device 17 or charge control device 20.

Figure 15 shows an eighth embodiment 47 of the device according to the invention, which emerges from the seventh embodiment 44 in that the ends of the outer wall 40 embedded in the outer electrodes 32 opposite to the ends of the embedded outer wall in the outer wall 41 outer electrodes 32 are arranged offset in the flow direction 30 against each other.

Figures 16 to 19 show a second implementation of the method according to the invention in the eighth embodiment 44 of the device with an electrode-spanning and advancing in the direction 27 advancing field excitation 19 "by three electrodes 32. The electric field lines deform the dielectric boundary layer 16 obliquely to the feed direction 27. Die Representation gives the field lines only qualitatively correct, surface tensions and capillary forces are disregarded.

Figures 20 to 23 show a third implementation of the method according to the invention in the eighth embodiment 44 of the device with progressive field excitation 19 "by means of a pair transverse to the feed direction 27 of oppositely disposed electrodes 32. The electric field lines distort the dielectric interface 16 qualitatively similar shown in Figures 16 to 19.

FIGS. 24 and 25 show a ninth embodiment 47 and a tenth embodiment 48 of the device according to the invention, each in cross section, the paper plane of the illustration being orthogonal to the flow direction 30 or feed direction 27. As in the case of conventional layered or wound capacitors, a high capacitance covering and thus a high feed force 27 'are achieved in that the thin internal electrodes 49 are arranged in a layered or wound manner. Instead of an electrolytic carrier film, as used in electrolytic capacitors or a plastic dielectric, which occurs in film capacitors, a permeable in the feed direction 27 support film 50 is provided.

Figure 24 shows a layer arrangement of plate-shaped, individual electrodes 49, which are enclosed by a closed, electrically conductive flow wall 12 of rectangular cross section, which is at ground potential 18. The electrodes 49 and the flow wall 12 are arranged separately from each other. Furthermore, the electrical connection of the internal electrodes 49 with an electric voltage source of the voltage control device 17 or a charge source of the charge control device 20 is provided.

Figure 25 shows a radial layer arrangement of circular, individual electrodes 49, which are enclosed by a closed, electrically conductive flow wall 12 of rectangular cross-section, which is at ground potential 18. The electrodes 49 and the flow wall 12 are arranged separately from each other. Furthermore, the electrical connection of the internal electrodes 49 with an electric voltage source of the voltage control device 17 or a charge source of the charge control device 20 is provided.

Claims (16)

1. Method for conveying at least one heat exchange medium (2, 66) which has at least one first fluid (3, 4, 5) which has a first permittivity and at least one second fluid (3, 4, 5) which does not mix with the first fluid (3, 4, 5) and has a second permittivity which is different from the first permittivity, at least one dielectric interface (16) being configured between the first and second fluid (3, 4, 5), which dielectric interface (16) is subjected to a progressively excited, electric advancing field (19) which exerts an advancing force (27') on the at least one dielectric interface (16), and the electric advancing field (19) being excited progressively by an electrode arrangement (14) which consists of at least two electrodes (7, 8, 9, 10, 11, 12, 13, 32, 49) which are adjacent, in particular in the advancing direction (27), each electrode (7, 8, 9, 10, 11, 12, 13, 32, 49) of the electrode arrangement (14) being assigned a voltage control apparatus (17) with independently controlled voltage sources or a charge control apparatus (20) with independently controlled charge sources.
2. Method according to Claim 1, characterized in that a first liquid is used as first fluid (3, 4, 5), and a second liquid, the permittivity of which differs from the permittivity of the first liquid, is used as second fluid (3, 4, 5).
3. Method according to either of the preceding claims, characterized in that a liquid is used as first fluid (3, 4, 5), and a gas is used as second fluid (3, 4, 5), in particular in that the gas is the gas phase (36) of the first fluid (3, 4, 5).
4. Method according to one of the preceding claims, characterized in that the advancing forces (27') on the heat exchange medium (2, 66) to be conveyed are generated by way of an electric field (19') which is excited by way of an electrode arrangement (14), in particular, in regions of dielectric interfaces (16) between fluids (3, 4, 5) of different permittivity.
5. Method according to one of the preceding claims, characterized in that the heat exchange medium (2, 66) is held together or forced together by means of a static electric field which is superimposed on the progressively excited electric advancing field (19).
6. Method according to one of the preceding claims, characterized in that the electric advancing field (19) is excited progressively by way of movement of the electric charge to further electrodes (7, 8, 9, 10, 11, 12, 13, 32, 49) of the electrode arrangement (14) in the advancing direction (27).
7. Method according to one of the preceding claims, characterized in that the position of at least one dielectric interface (16) in the heat exchange medium (2, 66) is determined by means of measurement of the capacitance of the field-exciting electrode arrangement (14), and the flow velocity of at least one fluid section (3', 4', 5') is determined from the temporal change of the position of at least one dielectric interface (16).
8. Method according to one of the preceding claims, characterized in that the temperature of at least one of the fluid sections (3', 4', 5') which are contained in the heat exchange medium (2, 66) is determined using the measured capacitance and at least one further parameter, in particular the temperature dependence of the permittivity of the fluid (3, 4, 5).
9. Method according to one of the preceding claims, characterized in that a heat flow is determined using the temperature, the flow velocity and the specific heat capacity of at least one fluid section (3', 4', 5') which is contained in the heat exchange medium (2, 66) .
10. Apparatus for conveying at least one heat exchange medium (2, 66) which has at least one first fluid (3, 4, 5) which has a first permittivity and at least one second fluid (3, 4, 5) which does not mix with the first fluid (3, 4, 5) and has a second permittivity which differs from the first permittivity, at least one dielectric interface (16) being configured between the first and the second fluid (3, 4, 5), characterized by a capacitive electrode arrangement (14) which consists of at least two electrodes (7, 8, 9, 10, 11, 12, 13, 32, 49) which are adjacent, in particular in the advancing direction (27), each electrode (7, 8, 9, 10, 11, 12, 13, 32, 49) of the electrode arrangement (14) being assigned a voltage control apparatus (17) with independently controlled voltage sources or a charge control apparatus (20) with independently controlled charge sources, the voltage control apparatus (17) being configured to vary the electric voltages which prevail at the electrodes (7, 8, 9, 10, 11, 12, 13, 32, 49) of the electrode arrangement (14), in such a way that an electric advancing field (19) is excited progressively by the electrode arrangement (14) in such a way that the at least one dielectric interface (16) is subjected to the progressively excited, electric advancing field (19) in such a way that the advancing field (19) exerts an advancing force (27') on the at least one dielectric interface (16), the advancing force (27') acting in the direction of increasing capacitance of the electrode arrangement (14) which excites the advancing field (19).
11. Apparatus according to Claim 10, characterized in that the conveying of the heat exchange medium (2, 66) takes place in a flow duct (6, 60) which extends into the intermediate spaces of the associated electrode arrangement (14).
12. Apparatus according to either of the preceding Claims 10 and 11, characterized in that the outer electrode (12, 13, 32) is configured as a closed outer wall (12', 13', 40, 41) of the flow duct (6, 60).
13. Apparatus according to Claim 12, characterized in that the further electrodes (7, 8, 9, 10, 11, 49) are enclosed completely by the outer electrode (12, 13, 32), the outer electrode (12, 13, 32) and the further electrodes (7, 8, 9, 10, 11, 49) being separated from one another.
14. Apparatus according to either of the preceding Claims 10 and 11, characterized in that at least two of the electrodes (7, 8, 9, 10) are configured as outer electrodes (12, 13, 32) which are separated from one another, the outer electrodes (12, 13, 32) being separated electrically from one another and being embedded into an electrically insulating outer wall (40, 41) or being fastened on the inner side of the outer wall (40, 41).
15. Apparatus according to Claim 14, characterized in that a further inner electrode (7, 8, 9, 10, 11, 49) is arranged in the interior of the flow duct (6, 60).
16. Apparatus according to one of the preceding Claims 10 to 15, characterized in that the electrode arrangement (14) has an apparatus for measuring at least one capacitance.

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