Abstract:
An apparatus includes a toroidal fluid mover. A drive mechanism rotates the toroidal fluid mover, such that the toroidal fluid mover directs axially received fluid at a smaller radius in a radial direction towards a greater radius to produce an axial-to-radial fluid flow field. A heat sink is positioned within the axial-to-radial fluid flow field. The heat sink is thermally coupled with a heat generating source and is at least partially filled with a fluid.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to heat transfer and cooling of electronic components, such as semiconductor chips used in computers and telecommunication equipment. More particularly, the invention relates to a toroidal fluid mover and associated heat sink. 
       BACKGROUND OF THE INVENTION 
       [0002]    As the power of semiconductor chips increases, more efficient cooling devices are required. Current cooling solutions have drawbacks in providing adequate cooling to chips in small spaces. Drawbacks include fan size and heat transfer inefficiencies stemming from low velocity fluid adjacent to heat sink surfaces. Current cooling solutions also have acoustic noise disadvantages from the periodic fluid flow and pressure pulsations inherent to fans with propellers or blades. This acoustic noise is a small scale version of the acoustic thumping of helicopter blades. This propeller, or blade induced, periodic fluid flow and pressure pulsations result in heat transfer inefficiencies. 
         [0003]    Therefore, it would be desirable to provide a cooling apparatus that obviates the aforementioned deficiencies in the prior art. 
       SUMMARY OF THE INVENTION 
       [0004]    In one embodiment of the invention, an apparatus includes a toroidal fluid mover. A drive mechanism rotates the toroidal fluid mover, such that the toroidal fluid mover directs axially received fluid at a smaller radius in a radial direction towards a greater radius to produce an axial-to-radial fluid flow field. A heat sink is positioned within the axial-to-radial fluid flow field. The heat sink is thermally coupled with a heat generating source and is at least partially filled with a fluid. 
         [0005]    In another embodiment of the invention, an apparatus includes a toroidal fluid mover with an outer perimeter. A drive mechanism rotates the toroidal fluid mover, such that the toroidal fluid mover directs axially received fluid at a smaller radius in a radial direction towards a greater radius to produce an axial-to-radial fluid flow field. A heat sink substantially surrounds the outer perimeter of the toroidal fluid mover and is thereby positioned within a radial region of the axial-to-radial fluid flow field. The heat sink is thermally coupled with a heat generating source positioned within the radial region of the axial-to-radial fluid flow field. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0006]    The invention is more fully appreciated in connection with the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0007]      FIG. 1  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile, and a hollow heat sink element; 
           [0008]      FIG. 2  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, and a heat sink element with attached heat sources; 
           [0009]      FIG. 3  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, and a heat sink element with a heat source attached to a parallel appendage; 
           [0010]      FIG. 4  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, and a heat sink element with a perpendicular appendage and an offset region, each with a heat source; 
           [0011]      FIG. 5  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a heat sink element with multiple perpendicular appendages and corresponding heat sources; 
           [0012]      FIG. 6  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a heat sink element with recessed and protruding regions and corresponding heat sources; 
           [0013]      FIG. 7  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a heat sink element with separate fluid pump and fluid coupled heat sources; 
           [0014]      FIG. 8  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a heat sink element with heat sources attached to a parallel appendage, and an embedded fluid pump; 
           [0015]      FIG. 9  depicts a three-dimensional (3-D) dimetric view of two toroidal fluid movers, each having a rectangular profile, and two heat sink elements joined by a perpendicular appendage with attached heat sources; 
           [0016]      FIG. 10  depicts a three-dimensional (3-D) dimetric view of two toroidal fluid movers, each having a rectangular profile, and having different rotational axes, an L-shaped heat sink element with heat sources, and an embedded fluid pump; 
           [0017]      FIG. 11  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a non-circular heat sink element with heat sources, an embedded fluid pump, and a radial section of extended surfaces; 
           [0018]      FIG. 12  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a non-circular heat sink element with heat sources, an embedded fluid pump, and a radial array of extended surfaces; 
           [0019]      FIG. 13  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a non-circular heat sink element with heat sources, an embedded fluid pump, and an array of extended surfaces; 
           [0020]      FIG. 14  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a non-circular heat sink element with heat sources, an embedded fluid pump, an array of extended surfaces, and a fluid flow diverting element; 
           [0021]      FIG. 15  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a non-circular heat sink element with heat sources, an embedded fluid pump, an array of extended surfaces, and a fluid flow diverting element, on two sides of the heat sink element; 
           [0022]      FIG. 16  depicts a three-dimensional (3-D) dimetric view of a toroidal fluid mover, having a rectangular profile, a portion of non-circular heat sink element with heat sources, and an embedded fluid pump; 
           [0023]      FIG. 17  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile and extended surface features, and a heat sink element with extended surface features; 
           [0024]      FIG. 18  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile and apertures, and a heat sink element; 
           [0025]      FIG. 19  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile and recessed surface features, and a heat sink element; 
           [0026]      FIG. 20  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile and a combination surface features, and a heat sink element; 
           [0027]      FIG. 21  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile, axially offset from a heat sink element; 
           [0028]      FIG. 22  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile, axially offset from two heat sink elements; 
           [0029]      FIG. 23  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile, axially offset from two heat sink elements having extended surface features; 
           [0030]      FIG. 24  depicts a three-dimensional (3-D) dimetric section view of two toroidal fluid movers, having rectangular profiles, axially offset from a heat sink element; 
           [0031]      FIG. 25  depicts a three-dimensional (3-D) dimetric section view of two toroidal fluid movers, having rectangular profiles, axially offset from a heat sink element having extended surface features; 
           [0032]      FIG. 26  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a trapezoidal profile, and a heat sink element; 
           [0033]      FIG. 27  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a trapezoidal profile, and a heat sink element having a trapezoidal profile; 
           [0034]      FIG. 28  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a leading edge feature, and a heat sink element; 
           [0035]      FIG. 29  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a trailing edge feature, and a heat sink element; 
           [0036]      FIG. 30  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a leading edge feature and non-planar surfaces, and a heat sink element; 
           [0037]      FIG. 31  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a curved profile, and a heat sink element; 
           [0038]      FIG. 32  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a curved profile with swept apertures, and a heat sink element; 
           [0039]      FIG. 33  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a curved profile with swept surface features, and a heat sink element; 
           [0040]      FIG. 34  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a curved profile with swept surface features, and a curved heat sink element; 
           [0041]      FIG. 35  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a curved profile, axially offset and overlapping a curved heat sink element; 
           [0042]      FIG. 36  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a rectangular profile, axially offset and overlapping a heat sink element; 
           [0043]      FIG. 37  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, having a substantially trapezoidal profile, with circumferential features, and a heat sink element having a substantially trapezoidal profile, with circumferential features; 
           [0044]      FIG. 38  depicts a three-dimensional (3-D) dimetric view of a rotating toroidal fluid mover, having a revolved spiral cut, and a heat sink element; 
           [0045]      FIG. 39  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, and a heat sink element, both having a rectangular profile, and a cut plot of velocity contours, from a computational fluid dynamics (CFD) analysis; 
           [0046]      FIG. 40  depicts a three-dimensional (3-D) dimetric section view of a toroidal fluid mover, and a heat sink element, both having a curved profile, and a cut plot of velocity contours, from a computational fluid dynamics (CFD) analysis. 
       
    
    
       [0047]    Like reference numerals refer to corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0048]      FIG. 1  depicts the cooling device of the present invention. As shown in the sectioned view of  FIG. 1 , the cooling device includes a rotating toroidal fluid mover  20  and a heat sink element  21 . The toroidal fluid mover  20  is in the shape of a toroid. A toroid has an annular shape that is generated by revolving a geometrical figure around an axis external to that figure. When a rectangle is rotated around an axis parallel to one of its edges then a hollow cylinder is produced. If the revolved geometrical figure is a circle, then a torus is produced. As illustrated below, the invention may be implemented with various geometrical figures, such as trapezoids. 
         [0049]    A motor  22  or other rotational means is attached to the toroidal fluid mover  20  by spokes  26 . Motor rotation creates a centrifugal force resulting in a relatively high fluid flow and therefore relatively low pressure region near the outer periphery  23 . Conversely, there is a relatively low fluid flow and therefore relatively high pressure region near the inner periphery  24 . Fluid (e.g., air) from the environment moves axially toward the toroidal fluid mover. At each ingress point, the fluid is forced radially outward toward the low pressure region  23 . This general flow path is shown with arrow  19 . Although fluid flow pattern  19  is shown on one side, a mirror image of this fluid flow pattern is also on the opposite side of the radial plane. 
         [0050]    This axial to radial fluid flow field enjoys mechanical efficiency due to the uninterrupted non-periodic nature of the fluid mover&#39;s smooth toroidal geometry. This mechanically efficient fluid flow field is directed toward the heat sink element  21 , which is positioned within the flow field allowing heat from the heat sink element  21  to be efficiently transferred to this flow field. Furthermore, heat generating devices coupled to the heat sink&#39;s heat transfer surfaces experience high heat transfer efficiency to this flow field. Rotating toroidal fluid mover  20  may be fabricated from solid, hollow, or porous materials. Heat sink element  21  may also be fabricated from solid, hollow, or porous materials. The heat sink element may have at least one interior void  25  at least partially filled with fluid. This fluid may be free convecting, forced convecting, capillary driven, or moved by any other fluid moving means. 
         [0051]      FIG. 2  depicts a rotating toroidal fluid mover  20 , and a heat sink element  21  having attached heat sources  27 . Additionally, heat sink element  21  may be an electrical circuit board, have an electrical circuit means incorporated thereon, or separately attached. Heat sources may be attached directly or indirectly, through a circuit board attachment, or any other heat source packaging or attachment means. 
         [0052]      FIG. 3  depicts a rotating toroidal fluid mover  20 , and a heat sink element  21  having heat source  27  attached to coplanar appendage  28 . This appendage provides additional area for the attachment of heat sources. 
         [0053]      FIG. 4  depicts a rotating toroidal fluid mover  20 , and a heat sink element  21  having heat source  27  attached to non-coplanar appendage  29 . This appendage also provides additional area for the attachment of heat sources. Further, this non-coplanar appendage may be optimized to improve fluid flow field impingement. This figure also depicts an offset region  29 B with an associated heat source  27 . This offset region allows thermal communication with heat sources that are not coplanar with heat sink  21 . Although appendage  29  is shown as being perpendicular to heat sink  21 , and an offset region  29 B is shown as parallel to heat sink  21 , these features may have any spatial orientation. This spatial orientation may be optimized for fluid dynamic drag and fluid flow field impingement for improved heat transfer efficiency. 
         [0054]      FIG. 5  depicts a rotating toroidal fluid mover  20  and a heat sink element  21  having heat source  27  attached to multiple non-coplanar appendages  29 . These multiple appendages provide additional area for the attachment of heat sources. These appendages may also have independent spatial orientation. These orientations may be optimized for non-thermal goals, such as converging or diverging LED light source angles. 
         [0055]      FIG. 6  depicts a rotating toroidal fluid mover  20  and a heat sink element  21  having attached heat sources  27 , at least partially within recessed regions  30 . The recessed heat sources may be optimized for lower fluid dynamic drag and fluid flow field impingement.  FIG. 6  also depicts heat sink element  21  having protruded regions  30 B and corresponding heat sources  27 . Although recessed regions  30  and protruded regions  30 B are shown as parallel to heat sink  21 , these features may have any spatial orientation, and this spatial orientation may be optimized for fluid dynamic drag and fluid flow field impingement, resulting in improved heat transfer efficiency. 
         [0056]      FIG. 7  depicts a rotating toroidal fluid mover  20  and a heat sink element  21  having a separate heat distribution means  31 , a separate fluid pump  32 , and fluid interconnect  33 . Heat from attached heat source  27  migrates to heat distribution means  31  and is further distributed to heat sink element  21  through an internal fluid circuit within heat sink element  21 . Fluid circulation is provided by fluid pump  32  and fluid interconnect  33 . 
         [0057]      FIG. 8  depicts a rotating toroidal fluid mover  20  and a heat sink element  21  having multiple heat sources  27  attached to a bifurcated coplanar appendage  34 . This bifurcated appendage provides additional area for the attachment of heat sources. Heat from attached heat sources  27  is distributed to heat sink element  21  through an internal fluid circuit within heat sink element  21 . Fluid circulation is provided by fluid pump  35 . Additionally, appendage  34  may have an internal fluid circuit, which may be interconnected with the fluid circuit within heat sink element  21 . Fluid pump  35  may be at least partially embedded into heat sink element  21 , or may be at least partially embedded into appendage  34 . 
         [0058]      FIG. 9  depicts two rotating toroidal fluid movers  20  and two heat sink elements  21  interconnected by heat sink element interconnect appendage  36 . Heat sources  27  are attached to heat sink element interconnect appendage  36 . Having multiple rotating toroidal fluid movers  20  and two heat sink elements  21  allows for improved cooling. Although the two rotating toroidal fluid movers  20  are shown as being parallel and on the same rotational axis, they may be oblique and have independent axes. Further, the rotating toroidal fluid movers  20  and heat sink elements  21  may have independent design elements, such as materials, construction, size, shape, angular velocity, and angular direction. Still further, the number of fluid movers and heat sink elements may not be equal, and may be greater than two. 
         [0059]      FIG. 10  depicts two rotating toroidal fluid movers  20  and an L-shaped heat sink element  37  having multiple heat sources  27  attached. Heat from attached heat sources  27  is distributed to L-shaped heat sink element  37  through an internal fluid circuit within heat sink element  37  by fluid circulation means provided by fluid pump  35 . Heat is removed from heat sink element  37  and from heat sources  27  by fluid moving along their surfaces. Fluid pump  35  may be at least partially embedded into heat sink element  37 . Heat sink element  37  may have an electrical circuit means incorporated thereon, or may be separately attached. This electrical circuit means may provide at least communication and power to heat sources and other electrical components, including fluid pump  35 . Heat sources may be attached directly or indirectly, through a circuit board attachment, or any other heat source packaging or attachment means. The two rotating toroidal fluid movers  20  have different sizes and independent rotational axes. Further, the rotating toroidal fluid movers  20 , and heat sink elements  21  may have independent design elements, such as materials, construction, size, shape, angular velocity, and angular direction. Still further, the number of fluid movers and heat sink elements are not equal. 
         [0060]      FIG. 11  depicts a rotating toroidal fluid mover  20  and a non-circular heat sink element  37  having multiple heat sources  27  attached. Additionally, a radial section of extended surfaces  38  is attached to non-circular heat sink element  37 . Heat from attached heat sources  27  is distributed to extended surfaces  38  through heat sink element  37 . Heat is transferred from heat sink element  37  and extended surfaces  38  to moving fluid provided by toroidal fluid mover  20 . Extended surfaces  38  improve heat transfer efficiency by increasing surface area within the fluid flow field generated by toroidal fluid mover  20 . Heat sink element  37  may be solid, partially filled with a phase changing fluid, or any other heat transfer body. Heat sink element  37  may have an electrical circuit incorporated thereon, or may be separately attached. The electrical circuit may provide at least communication and power to heat sources and other electrical components. 
         [0061]      FIG. 12  depicts a rotating toroidal fluid mover  20  and a non-circular heat sink element  37  having multiple heat sources  27  attached. Additionally, a radial array of extended surfaces  39  is attached to non-circular heat sink element  37 . Heat from attached heat sources  27  is distributed to extended surfaces  39  through an internal fluid circuit within heat sink element  37  by fluid circulation means provided by fluid pump  35 . 
         [0062]      FIG. 13  depicts a rotating toroidal fluid mover  20  and a non-circular heat sink element  37  having multiple heat sources  27  attached. Additionally, an array of extended surfaces  40  is attached to non-circular heat sink element  37 . Heat from attached heat sources  27  is distributed to extended surfaces  40  through an internal fluid circuit within heat sink element  37 . Heat distribution may be enhanced by fluid circulation means provided by fluid pump  35 . 
         [0063]      FIG. 14  depicts a rotating toroidal fluid mover  20 , and a non-circular heat sink element  37  having multiple heat sources  27  attached. Similar to  FIG. 13 , an array of extended surfaces  40  is attached to non-circular heat sink element  37 . Additionally, a fluid flow diverting element  41  redirects the fluid flow from the rotating toroidal fluid mover  20 , toward the array of extended surfaces  40 . Heat from attached heat sources  27  is distributed to extended surfaces  40  through an internal fluid circuit within heat sink element  37 . Fluid circulation may be enhanced with fluid pump  35 . Heat is transferred from heat sink element  37  and extended surfaces  40  to moving fluid provided by toroidal fluid mover  20 . Further, redirected fluid flow from fluid flow diverting element  41  provides additional benefits, such as cooling additional components within its flow field or redirecting fluid flow to an enclosure fluid exit. 
         [0064]      FIG. 15  depicts a rotating toroidal fluid mover  20  and a non-circular heat sink element  37  having multiple heat sources  27  attached. Similar to  FIG. 14 , two arrays of extended surfaces  40  and fluid flow diverting elements  41  are attached to opposite sides of non-circular heat sink element  37 . Having multiple arrays of extended surfaces, as well as multiple fluid flow diverting elements redirecting fluid flow toward those extended surfaces improves heat transfer efficiency. 
         [0065]      FIG. 16  depicts a rotating toroidal fluid mover  20  and a non-circumferentially encompassing heat sink element  42  having multiple heat sources  27  attached. This non-circumferentially encompassing heat sink element  42  allows additional degrees of design freedom, such as a toroidal fluid mover that is larger than the heat sink element or a single toroidal fluid mover used between two or more heat sink elements. 
         [0066]      FIG. 17  depicts a rotating toroidal fluid mover  20  having extended surface features  43  and a heat sink element  21  having extended surface features  44 . These extended surface features may, or may not have the same design goal, and may be independently optimized. For instance, extended surface features  43  on fluid mover  20 , may be optimized to promote fluid flow by increasing surface area, while extended surface features  44  may be optimized to improve heat transfer efficiency by also increasing surface area. Although these extended surface features are shown as hemispherical they may have any shape, size, quantity, or pattern. Additionally, they may be on one or more surfaces and may have varying positional density. Further, these extended surface features may have multiple shapes and sizes on any given surface. 
         [0067]      FIG. 18  depicts a rotating toroidal fluid mover  20  having apertures  45 . These apertures may have multiple design goals, such as, improving fluid flow or reducing sound pressure. For instance, apertures closer to the rotational axis, or center, may be optimized for improving mass fluid flow rate, by having larger size and increasing surface area, while apertures near the outer periphery may be optimized for reducing sound pressure, by having smaller size and radially staggered. Although these apertures are shown as cylindrical, they may have any shape, size, quantity or pattern. Additionally, they may be on one or more surfaces and may have varying positional density. Further, these apertures may have multiple shapes and sizes on any given surface. 
         [0068]      FIG. 19  depicts a rotating toroidal fluid mover  20  having recessed surface features  46 . These recessed surface features, similar to those on a golf ball, may have multiple design goals, such as, improving fluid flow or reducing rotational torque, thus horsepower. For instance, recessed features closer to the rotational axis, or center, may be optimized for improving mass fluid flow rate, by having larger size and increasing surface area and edges, while recessed features near the outer periphery may be optimized for reducing rotational torque, by being smaller and radially staggered, like a golf ball. Although these recessed surface features are shown as hemispherical, they may have any shape, size, quantity, or pattern. Additionally, they may be on one or more surfaces, and may have varying positional density. Further, these recessed surface features may have multiple shapes and sizes on any given surface. 
         [0069]      FIG. 20  depicts a rotating toroidal fluid mover  20  having both extended surface features  43  and apertures  45 . This combination of extended surface features and apertures provides additional design degrees of freedom, such as increasing fluid flow while decreasing sound and rotational torque. For instance, extended surface features closer to the lower velocity centroid may be optimized for increasing mass fluid flow rate, while simultaneously optimizing apertures near the higher velocity outer periphery, toward a lower sound pressure goal. Although two types of features are shown, any combination of features may be used, including extended, recessed, or aperture type. Additionally, they may be on one or more surfaces, and may have varying positional density. Further, these surface features may be extended, recessed, or apertures, and may have multiple shapes and sizes on any given surface. 
         [0070]      FIG. 21  depicts a rotating toroidal fluid mover  20  and a heat sink element  21 , where the rotational plane of the toroidal fluid mover  20  is not coplanar with heat sink element  21 . Offsetting the fluid mover plane from the heat sink element plane offsets the fluid flow field from the heat sink element plane. This offset allows more fluid flow on the offset side of the heat sink element. This offset feature provides cooling improvement when axial fluid intake is at least partially restricted from either axial side. Although the fluid mover plane is shown parallel to the heat sink element plane, these planes may not be coplanar or parallel. 
         [0071]      FIG. 22  depicts a rotating toroidal fluid mover  20  and two heat sink elements  21 , where the rotational plane of the toroidal fluid mover  20  may not be coplanar with either heat sink element  21 . Offsetting the fluid mover plane from the heat sink element plane offsets the fluid flow field from the heat sink element plane. This offset allows more fluid flow on the offset side of the heat sink element. This offset embodiment provides cooling improvement when fluid flow on one or both exterior heat sink surfaces may be at least partially restricted, such as proximate surfaces or attached heat generating devices. 
         [0072]      FIG. 23  depicts a rotating toroidal fluid mover  20  and two heat sink elements  21 , having extended surface features  46  interposed. The rotational plane of toroidal fluid mover  20  may not be coplanar with either heat sink elements  21 . These interposed extended surface features  46  are within the highest velocity region of the fluid flow field generated by this offset rotating toroidal fluid mover  20 . Being within this high velocity region, these interposed extended surface features  46  have higher heat transfer efficiency. Although these interposed extended surface features  46  are show as cylindrical, they may have any shape, including multiple shapes, size, quantity, pattern, and may have varying positional density. In addition, interposed extended surface features may be optimized to provide a thermal path between the two heat sink elements, when the thermal load or cooling requirement of the heat sink elements is not equal. 
         [0073]      FIG. 24  depicts two rotating toroidal fluid movers  20 , where the rotational planes of the toroidal fluid movers  20  may or may not coplanar with heat sink element  21 . Offsetting the fluid mover planes from the heat sink element plane offsets the fluid flow fields from the heat sink element plane. These offset fluid flow fields allow more fluid flow on both sides of the heat sink element, for increased heat transfer efficiency. Although a single motor  22  may have multiple toroidal fluid movers, each rotating toroidal fluid mover  20  may have an independent motor. These independent motors may have different size, horsepower, angular velocity, and angular direction. 
         [0074]      FIG. 25  depicts two rotating toroidal fluid movers  20  and a heat sink element  21  with extended surface features  47  on opposing sides. The rotational planes of toroidal fluid movers  20  may not be coplanar with heat sink element  21 . The extended surface features  47  are within the highest velocity region of the fluid flow fields generated by these offset rotating toroidal fluid movers  20 . Being within this high velocity region, these extended surface features  47  have higher heat transfer efficiency. Although these extended surface features  47  are show as cylindrical, they may have any shape, including multiple shapes, size, quantity, pattern, and may have varying positional density. 
         [0075]      FIG. 26  depicts a rotating toroidal fluid mover  20 , having a trapezoidal cross-section  48 . The trapezoidal cross-sectional shape of fluid mover  48  corresponds to the shape of its resulting fluid flow field. Changing the cross-sectional shape of the fluid mover will change the shape of the fluid flow field. This trapezoidal shaped fluid flow field will direct fluid toward the heat sink element at a more acute angle. This more acute angle will result in fluid impinging on the heat sink element, increasing heat transfer efficiency. Although the toroidal fluid mover with a trapezoidal cross-section is shown, many shapes may result in fluid impinging on the heat sink element, including irregular shapes, shapes with protrusions, or bifurcated shapes. 
         [0076]      FIG. 27  depicts a rotating toroidal fluid mover  20  having a trapezoidal cross-section  48  and a heat sink element  21  having a trapezoidal cross-section  49 . Although the fluid mover and heat sink element cross-sections have similar shapes with different dimensions, the primary surfaces on each side are coplanar, unlike  FIG. 26 . Although the toroidal fluid mover and heat sink element have coplanar surfaces, the fluid flow pattern will result in fluid impinging on the heat sink element, since the trapezoidal heat sink element will cause further widening of the fluid flow field. This further widening or the flow field, changes the fluid flow field direction, which results in more friction on the heat sink element surfaces. This additional friction improves heat transfer efficiency of the heat sink element. 
         [0077]      FIG. 28  depicts a rotating toroidal fluid mover  20  having a trapezoidal cross-section  48  with a leading edge feature  50 . Heat sink element  21  also has a trapezoidal cross-section  49 . The shape of leading edge feature  50  may be optimized to improve the mass fluid flow rate, by increasing surface area. Although, the trapezoidal shaped heat sink element is narrowing at the outer periphery, and may not cause widening of the flow field, it will cause the fluid flow field to converge, resulting in less aerodynamic drag, thereby reducing the fluid mover&#39;s rotational torque and horsepower. 
         [0078]      FIG. 29  depicts a rotating toroidal fluid mover  20  with a trailing edge feature  51 . The shape of trailing edge feature  51  may be optimized to create turbulence on the heat sink element. This turbulent fluid flow field increases fluid impingement on the heat sink element, which increases the heat transfer efficiency of the heat sink element. 
         [0079]      FIG. 30  depicts a rotating toroidal fluid mover  20  with curved surface feature  52 . The curved surface feature  52  may be optimized to promote the fluid flow transition from axial to radial, thereby improving the fluid flow efficiency. Curved surface feature  52  is shown as symmetrical about the rotating fluid mover plane; however, these opposing surfaces need not be symmetrical. For example, the curved surface feature may be more pronounced on one side, if the axial fluid flow intake is at least partially restricted from the non-curved side. 
         [0080]      FIG. 31  depicts a rotating toroidal fluid mover  20  with coradially curved surfaces  53  and  54 . The coradially curved surfaces may be optimized to promote the fluid flow transition from axial to radial, thereby improving fluid flow efficiency. Additionally, this curved toroidal fluid mover may have axially asymmetrical fluid flow rates. This axially asymmetrical fluid flow may be optimized to increase the total mass flow rate, where the axial fluid entrance on the convex side of the toroidal fluid mover may be at least partially obstructed. 
         [0081]      FIG. 32  depicts a rotating toroidal fluid mover  20  with coradially curved surfaces  53  and  54  having leading edge swept aperture  55  and trailing edge swept aperture  56 . The shapes of these swept apertures may be optimized to improve the mass fluid flow rate and overall pressure. Although these swept apertures are shown as spiral shaped, they may have any shape, size, quantity, or pattern. Further, these swept features may be recessed from one or both sides, and may not be through features. 
         [0082]      FIG. 33  depicts a rotating toroidal fluid mover  20  with coradially curved surfaces  53  and  54  having swept protruding surface features  57 . These swept protruding surface features may be optimized to improve the mass fluid flow rate and overall pressure. Although these swept surface features are shown as spiral shaped, they may have any shape, size, quantity, or pattern. Furthermore, these swept protruding surface features may be on one side only, or may be more pronounced on either side. Although shown as symmetrical on both sides, these protruding swept surface features may be asymmetrical 
         [0083]      FIG. 34  depicts a rotating toroidal fluid mover  20  with coradially curved surfaces  53  and  54 . Heat sink element  21  also has coradially curved surfaces  58  and  59 . Combining coradially curved fluid mover and heat sink element surfaces may be optimized to further promote the fluid flow transition from axial to radial, thereby further improving the fluid flow efficiency. Additionally, this curved toroidal fluid mover may have axially asymmetrical fluid flow rates. This axially asymmetrical fluid flow may be optimized to increase the total mass flow rate, where the axial fluid entrance on the convex side may be at least partially obstructed. 
         [0084]      FIG. 35  depicts a rotating toroidal fluid mover  20 , with coradially curved surfaces  53  and  54  and a heat sink element  21  having coradially curved surfaces  58  and  59 . All four curved surfaces  53 ,  54 ,  58 , and  59 , may be coradial, resulting in a spherically shaped assembly. In addition, the toroidal fluid mover  20  is offset from the heat sink element  21 . Further, the toroidal fluid mover  20  is at least partially overlapping the heat sink element  21 . Since the fluid flow field is redirected by the curved surface of the heat sink element, the heat sink element enjoys the fluid flow impingement of such redirection, thereby improving the heat sink element heat transfer efficiency. 
         [0085]      FIG. 36  depicts a rotating toroidal fluid mover  20  and a heat sink element  21 . In addition, the toroidal fluid mover  20  is offset from the heat sink element  21 . Further, the toroidal fluid mover  20  is at least partially overlapping the heat sink element  21 . This overlapping region may be optimized to increase the heat transfer efficiency due to the close proximity of the overlapping surfaces. Although shown as partially overlapping, the toroidal fluid mover and heat sink element may be completely overlapping. Further, the toroidal fluid mover and heat sink element may be completely overlapping, where one or more radial boundaries exceed the other. 
         [0086]      FIG. 37  depicts a rotating toroidal fluid mover  20  having a substantially trapezoidal cross-section with circumferential features  60 . Heat sink element  21  has a substantially trapezoidal cross-section, with circumferential features  61 . Circumferential feature  60  may be optimized to improve the mass fluid flow rate and overall pressure by disrupting the laminar flow and creating turbulence, thereby reducing the laminar thickness. Circumferential feature  61  may be optimized to improve heat transfer efficiency by also disrupting the laminar flow and creating turbulence, thereby increasing fluid impingement and reducing the laminar thickness. Circumferential features may be any revolved boss or cut, such as steps (as shown), protuberances, recessions, or apertures. 
         [0087]      FIG. 38  depicts a rotating toroidal fluid mover  20  having a revolved spiral cut feature  62 . Similar to circumferential feature  61 , revolved spiral cut feature  62  may be optimized to improve the mass fluid flow rate and overall pressure, by disrupting the laminar flow from the toroidal fluid mover, and creating turbulence near the heat sink element, thereby reducing the laminar thickness on the heat sink element and thus improving heat transfer efficiency. The spiral shaped fluid mover has two ends  63  and  64 . Depending on the angular direction, spiral ends  63  and  64  may be leading or trailing edges. For instance, from the viewer&#39;s perspective, if fluid mover  20  is rotating counter-clockwise, spiral end  63  will be the leading edge, and spiral end  64  will be the trailing edge. If fluid mover  20  is rotating clockwise, spiral end  64  will be the leading edge, and spiral end  63  will be the trailing edge. The leading edge of revolved spiral cut feature  62  may provide a fluid skiving affect, which increases local fluid velocity, and reduces local pressure, thereby improving flow from the higher pressure environment toward the lower pressure leading edge. 
         [0088]    Therefore, from the viewer&#39;s perspective, if the spiral shaped fluid mover were rotating counter-clockwise, the fluid would flow axially from the higher pressure environment toward a smaller radius near leading edge  63 , then turn and flow radially outward toward a larger radius near trailing edge  64 , similar to  FIG. 1  fluid flow pattern  19 . Further, if the spiral shaped fluid mover were rotating clockwise, the fluid may flow radially inward from the higher pressure environment toward a larger radius near leading edge  64 , then flow further radially inward toward a smaller radius near trailing edge  63 , then turn and flow axially away from the spiral shaped fluid mover, which is the reverse direction of  FIG. 1  fluid flow pattern  19 . This reversed radial to axial fluid flow pattern allows greater overall design freedom. 
         [0089]      FIG. 39  depicts a section view of a rotating toroidal fluid mover  20 , having an inside and outside radius of 35 mm and 60 mm respectively, rotating at 3,000 RPM, and a stationary heat sink element  21 , having an inside and outside radius of 61 mm and 85 mm respectively, with a cut plot plane  65 , showing the velocity contours  66  and a velocity scale  67 . The fluid mover and heat sink shapes are similar to  FIG. 1 . The velocity contour  66  was derived using three dimensional (3D) computational fluid dynamics (CFD) analysis. This velocity contour clearly demonstrates the high velocity fluid flow field that is generated by the toroidal fluid mover. Further, it clearly depicts the high velocity fluid flow field engulfing the heat sink element. It even further depicts the high velocity fluid flow being fairly uniform on the primary planar surfaces of the heat sink element. Having heat sink element  21  surrounded by this high velocity fluid flow field and having high velocity fluid flow adjacent to the heat sink element primary planar surfaces, allows heat from the heat sink element to be efficiently transferred to this flow field. The average heat transfer coefficient on the surfaces of the heat sink element  21  is 59.9 W/m 2 /° K (watts per square meter per degree Kelvin), and the maximum heat transfer coefficient is 1,378 W/m 2 /° K. This translates to an average heat sink element surface temperature rise above ambient of 64.6° C. with a 100 watt heat load, or a thermal resistance of 0.646° C./W (degrees Centigrade per watt). Further, the volumetric efficiency of this embodiment is 0.136 W/° C./cc (watts per degree Centigrade per cubic centimeter); where current state of the art forced convection heat sinks have volumetric efficiencies around 0.003 W/° C./cc, which translates to a 4,400% (45 times greater) volumetric efficiency. 
         [0090]      FIG. 40  depicts a section view of a rotating toroidal fluid mover  20  having a curved profile with an inside and outside radius of 35 mm and 60 mm, respectively, rotating at 3,000 RPM. A stationary heat sink element  21  has a curved profile with an inside and outside radius of 61 mm and 85 mm, respectively. A cut plot plane  65  shows the velocity contours  68  and a velocity scale  67 . The fluid mover and heat sink shapes are similar to  FIG. 34 . The velocity contour  66  was derived using three dimensional (3D) computational fluid dynamics (CFD) analysis. This velocity contour clearly demonstrates the high velocity fluid flow field that is generated by the toroidal fluid mover. Further, it clearly depicts the high velocity fluid flow field engulfing the heat sink element. It also depicts the high velocity fluid flow being fairly uniform on the primary planar surfaces of the heat sink element. This velocity contour further depicts a more turbulent profile, than depicted in  FIG. 39 . Having heat sink element  21  surrounded by this high velocity fluid flow field and having high velocity fluid flow adjacent to the heat sink element primary planar surfaces allows heat from the heat sink element to be efficiently transferred to this flow field. The average heat transfer coefficient on the surfaces of the heat sink element  21  is 103.6 W/m 2 /K° (watts per square meter per degree Kelvin), and the maximum heat transfer coefficient is 1,870 W/m 2 /K°. This translates to an average heat sink element surface temperature rise above ambient of 38.1° C. with a 100 watt heat load, or a thermal resistance of 0.381 C/W. Further, the volumetric efficiency of this embodiment is 0.231 W/° C./cc (watts per degree Centigrade per cubic centimeter); where current state of the art forced convection heat sinks have volumetric efficiencies around 0.003 W/° C./cc, which translates to a 7,600% (77 times greater) volumetric efficiency. Notice the substantial heat transfer improvement over the embodiment described in  FIG. 39 . Given the size and rotational speed is the same as that in  FIG. 39 , the heat transfer improvement may be attributed to the fluid flow field shape. Since the primary surfaces of the heat transfer element are both curved, the fluid flow adjacent to these surfaces is more turbulent and less laminar. This turbulent flow is clearly seen in the velocity contour  68 , especially when compared to the velocity contour  66 . 
         [0091]    The 70% performance improvement of  FIG. 40  over  FIG. 39  by virtue of curved surfaces, demonstrates the performance improvement potential of the various surface features described herein, such as fluid flow directional impingement, protuberances, recessions and apertures. 
         [0092]    Thus, embodiments of the invention provide high velocity fluid movement. This is accomplished without measurable fluid flow pulsations. Thus, the invention provides for acoustic improvements over prior art fluid movers. 
         [0093]    The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, they thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.