ELECTROHYDRODYNAMICS SYSTEM AND METHOD

Abstract

A method for altering one or more properties of a dielectric fluid for use in an electrohydrodynamic, EHD, thermal management system (100), as well as the system, are provided. The system comprises at least one EHD pump unit (110) comprising at least two electrodes for pumping the dielectric fluid and at least one enclosure (120) for accommodating the fluid within the system. The method comprises exposing the dielectric fluid to an ionizing process (122) configured to ionize the dielectric fluid, and operating the pump unit to circulate the exposed fluid in the enclosure.

Claims

1.-15. (canceled)

16. A method for use in an electrohydrodynamic (EHD) thermal management system, the method comprising: exposing a dielectric fluid to an ionizing irradiation from a radiating source, thereby ionizing the dielectric fluid; and operating at least one EHD pump unit comprising at least two electrodes for pumping the dielectric fluid to circulate the exposed fluid in an enclosure for accommodating the dielectric fluid within the system; wherein the dielectric fluid is exposed to the ionizing irradiation in at least one of: a part of said enclosure, wherein a wall portion of the enclosure is exposed to said ionizing irradiation; a location separated from said EHD thermal management system, from which location the dielectric fluid is added to said EHD thermal management system after exposure; or within said enclosure, wherein the dielectric fluid is exposed to the ionizing irradiation by a substance located within said enclosure.

17. The method of claim 16, wherein the ionizing irradiation is generated from at least one of a radioactive isotope or an electrically generated X-ray radiation.

18. The method of claim 16, wherein the dielectric fluid is a fluorinated fluid or a hydrocarbon fluid.

19. The method of claim 16, wherein the dielectric fluid further comprises at least one additive.

20. The method of claim 16, wherein the enclosure is formed as an enclosed passage adapted to convey a circulating flow of the dielectric fluid.

21. The method of claim 20, wherein the EHD pump unit is arranged to cover an entire cross section of the passage.

22. The method of claim 16, wherein the at least two electrodes are formed as grid structures.

23. An electrohydrodynamic (EHD) thermal management system comprising: a radiating source; at least one pump unit comprising at least two electrodes for pumping a dielectric fluid; and at least one enclosure for accommodating said dielectric fluid; wherein the system is configured to expose the dielectric fluid to an ionizing irradiation from the radiating source to ionize the dielectric fluid.

24. The EHD thermal management system of claim 23, wherein the dielectric fluid is exposed to the ionizing irradiation from the radiating source in at least one of: a part of said enclosure, wherein a wall portion of the enclosure is exposed to said ionizing irradiation; a location separated from said EHD thermal management system, from which location the dielectric fluid is added to said EHD thermal management system after exposure; or within said enclosure, wherein the dielectric fluid is exposed to the ionizing irradiation by a substance located within said enclosure.

25. The EHD thermal management system of claim 24, wherein the ionizing irradiation is generated from at least one of a radioactive isotope and an electrically generated X-ray radiation.

26. The EHD thermal management system of claim 23, wherein the dielectric fluid is selected from the group consisting of a fluorinated fluid and a hydrocarbon fluid.

27. The EHD thermal management system of claim 23, wherein the dielectric fluid further comprises at least one additive.

28. The EHD thermal management system of claim 23, wherein the enclosure is formed as an enclosed passage adapted to convey a circulating flow of the dielectric fluid.

29. The EHD thermal management system of claim 28, wherein the pump unit is arranged to cover an entire cross section of the passage.

30. The EHD thermal management system of claim 23, wherein the at least two electrodes are formed as grid structures.

31. An electrohydrodynamic (EHD) thermal management system comprising: dielectric fluid that has been exposed to a radiation source to afford irradiated dielectric fluid; at least one enclosure for accommodating the irradiated dielectric fluid; at least one EHD pump unit comprising at least two electrodes for pumping the irradiated dielectric fluid to circulate the irradiated dielectric fluid in the enclosure.

32. The EHD thermal management system of claim 31, wherein the at least two electrodes are formed as grid structures.

33. The EHD thermal management system of claim 32, wherein the at least two electrodes bridge an entire cross section of a passage disposed in the enclosure.

34. The EHD thermal management system of claim 31, wherein the radiation source is disposed within the enclosure.

35. The EHD thermal management system of claim 31, wherein the radiation source is disposed adjacent to a wall of the enclosure.

Description

DETAILED DESCRIPTION OF THE DRAWINGS

[0023] A few example embodiments of the invention will be described for illustrative purposes in the following.

[0024] FIG. 1 shows an EHD thermal management system 100 comprising a pump unit 110 and an enclosure 120 for dielectric fluid. Also displayed are a heat source H and a cooler area C, on opposite ends of the enclosure 120. A flow, F, is created by the pump unit 110, which in this embodiment may be located within the enclosure 120, where dielectric fluid is held. The flow F causes the dielectric fluid to circulate between the hot side H and the cooler area C so as to transport thermal energy from the heat source H towards the cooler area C.

[0025] FIG. 2 shows an EHD thermal management system 100 according to an embodiment. Here, the pump unit 110 and a device for exposing or subjecting the dielectric fluid to an ionizing process, exemplified as a radiation source 130, are located within the enclosure 120. The enclosure 120 is formed as a single chamber similar to the enclosure disclosed in FIG. 1. The pump unit 110 may be arranged to induce the flow F, preferably at a position relatively close or adjacent to a wall portion of the enclosure, to induce a motion or flow F of the fluid in a direction along the wall portion. The flowing dielectric fluid may be exposed to ionizing radiation 122 from the radiating source 130 located within the enclosure 120. The radiating source 130 may for example comprise a radioactive isotope such as Cobolt 60 or Americum. Other embodiments may utilize electrically generated X-ray radiation as an ionizing means. The setup with a radiating source 130 located within the enclosure may allow for the dielectric fluid to be continuously exposed to radiation 122 throughout the system's operation. This may result in increasing the lifespan of the irradiating effect on the dielectric fluid, and also providing EHD systems having a very long lifespan.

[0026] It should be noted that the dielectric fluid may be exposed to radiation at different points in time, locations, to a certain amount, or using different radiating source materials and dielectric fluids, and that the examples discussed with reference to the appended drawings merely are illustrative examples. According to some embodiments of the invention the fluid may be exposed to radiation separately from the EHD system and added to the system at a later stage. It will be appreciated that not the entire amount of said fluid has to be exposed to radiation. In some examples, exposed fluid could be added to the fluid in the EHD system, thus forming a radiated additive to the total amount of fluid in the system. It is also appreciated that the radiation may be provided from within the enclosure as well as from a source positioned outside the enclosure and/or the entire system. One example of such arrangement is disclosed in FIG. 3.

[0027] FIG. 3 depicts an embodiment in which the enclosure 120 is formed as a passage leading fluid through a closed loop. The enclosure 120 may e.g. be formed as a tube or channel wherein the end is connected to the beginning in order to allow for a continuous and repeated flow of a circulating fluid in a closed loop system.

[0028] The pump unit 110 may be arranged to cover an entire cross section of the enclosure 120, as indicated in FIG. 3. Alternatively, the pump unit 110 may cover only a part of the cross section in order to allow fluid to pass at the side of the pump unit 100. By arranging the pump unit 110 to cover the entire cross section of the passage 120, all fluid has to pass through the pump unit 110 in order to circulate. As a result, the pump unit 110 may not only be capable of inducing a flow F in the dielectric fluid, but also to impede or even prevent the flow F. In other words, the pump unit 110 may be configured to operate as a switch capable of opening and closing the passage 120, which allows for an improved control of the flow.

[0029] As already mentioned, the irradiation 122 of the fluid may in this example be provided from outside of the system. As depicted, part of the enclosure may be subject to ionizing radiation 122, which may penetrate the wall of the enclosure and reach the dielectric fluid. Other embodiments may have the enclosure 120 exposed to radiation 122 in its entity. The radiating source 130 may be placed directly on the system or distanced from it.

List of Embodiments

[0030] 1. A method for altering one or more properties of a dielectric fluid for use in an electrohydrodynamic, EHD, thermal management system (100), the system comprising at least one EHD pump unit (110) comprising at least two electrodes for pumping the dielectric fluid and at least one enclosure (120) for accommodating the fluid within the system, the method comprising: [0031] exposing the dielectric fluid to an ionizing process (122) configured to ionize the dielectric fluid; and [0032] operating the pump unit to circulate the exposed fluid in the enclosure; [0033] wherein the dielectric fluid is exposed to the ionizing process in at least one of: [0034] a part of said enclosure, wherein a wall portion of the enclosure is exposed to said ionizing process, [0035] a location separated from said EHD thermal management system, from which the fluid is added to said EHD thermal management system after exposure, and [0036] within said enclosure, wherein the dielectric fluid is exposed to the ionizing process by a substance (130) located within said enclosure. [0037] 2. The method according to embodiment 1, wherein the ionizing process comprises an ionizing irradiation of the dielectric fluid. [0038] 3. The method according to embodiment 2, wherein the ionizing irradiation is generated from at least one of a radioactive isotope and an electrically generated X-ray radiation. [0039] 4. The method according to any preceding embodiment, wherein the dielectric fluid is selected from the group consisting of a fluorinated fluid and a hydrocarbon fluid. [0040] 5. The method according to any preceding embodiment, wherein the dielectric fluid further comprises at least one additive. [0041] 6. The method according to any preceding embodiment, wherein the enclosure is formed as an enclosed passage adapted to convey a circulating flow of the fluid. [0042] 7. The method according to embodiment 6, wherein the pump unit is arranged to cover an entire cross section of the passage. [0043] 8. The method according to any preceding embodiment, wherein the at least two electrodes are formed as grid structures. [0044] 9. An electrohydrodynamic, EHD, thermal management system (100) comprising at least one pump unit (110) comprising at least two electrodes for pumping a dielectric fluid, and at least one enclosure (120) for accommodating said dielectric fluid, wherein the EHD thermal management system is configured to expose the dielectric fluid to an ionizing process (122) configured to ionize the dielectric fluid. [0045] 10. The EHD thermal management system according to embodiment 9, wherein the dielectric fluid is exposed to the ionizing process in at least one of: [0046] a part of said enclosure, wherein a wall portion of the enclosure is exposed to said ionizing process, [0047] a location separated from said EHD thermal management system, from which the fluid is added to said EHD thermal management system after exposure, and [0048] within said enclosure, wherein the dielectric fluid is exposed to the ionizing process by a substance (130) located within said enclosure. [0049] 11. The EHD thermal management system according to embodiment 9 or 10, wherein the ionizing process comprises an ionizing irradiation of the dielectric fluid. [0050] 12. The EHD thermal management system according to embodiment 11, wherein the ionizing irradiation is generated from at least one of a radioactive isotope and an electrically generated X-ray radiation. [0051] 13. The EHD thermal management system according to any of embodiments 9 -12, wherein the dielectric fluid is selected from the group consisting of a fluorinated fluid and a hydrocarbon fluid. [0052] 14. The EHD thermal management system according to any of embodiments 9 -13, wherein the dielectric fluid further comprises at least one additive. [0053] 15. The EHD thermal management system according to any of embodiments 9 -14, wherein the enclosure is formed as an enclosed passage adapted to convey a circulating flow of the fluid. [0054] 16. The EHD thermal management system according to embodiment 15, wherein the pump unit is arranged to cover an entire cross section of the passage. [0055] 17. The EHD thermal management system according to any of embodiments 8 -16, wherein the at least two electrodes are formed as grid structures.