Mikros Manufacturing, Inc.

Creare, Incorporated

Other

United States of America As Represented by the Secretary of the Air Force

Javier A Valenzuela

John A McCormick

Herbert Sixsmith

William E Nutt

Thomas J Jasinski

Stacy W Dodd

Timothy F Ryan

Adam E Sharp

Jesse D McGowan

Lucas H Rose

The present disclosure relates to a heat exchanger for thermal control of heat producing devices. In accordance with aspects and embodiments, this is achieved in the present design by placing a parallel flow path near the heat sink in the test head with a variable restriction in each flow path. The restrictions may be operated in a complementary manner to keep the fluid inertia in the main supply and return lines substantially constant. This arrangement results in a test head with higher cooling capacity and quicker response time than achievable with prior art semiconductor testing systems. The test head includes a pair of nested pneumatic actuators having non-circular pistons designed to provide Z axis motion and roll and tilt compliance. The pneumatic actuator assembly may be mounted on segmented flexures to provide X axis, Y axis and yaw compliance.

Heat exchanger for thermal control of heat producing devices

An active device with a heat sink and low mechanical stress comprises a heat-producing substrate having a first thermal expansion coefficient; a heat sink having a second thermal expansion coefficient, wherein the first and second thermal expansion coefficients are different; and an interface between the heat-producing substrate and the heat sink formed so that, when the heat-producing substrate is operating at a predetermined temperature, a mechanical stress between the heat-producing substrate and the heat sink is substantially minimized. The heat sink has a yield strength that is lower than a yield strength of the heat-producing substrate and has been plastically deformed during fabrication to minimize the stress between the heat-producing substrate and the heat sink. Methods for fabricating the device are also disclosed.

Active device with heat sink and low mechanical stress

A micro-channel heat exchanger suited for use in large-area cold plates includes a heat transfer member having winding micro-channels, a manifold, and a cover plate. The micro-channels' winding design is defined by a nonlinear flow axis that may include a plurality of short pitch and small amplitude undulations, which cause the flow to change directions, as well as two or more large amplitude bends that cause the flow to reverse direction. In low flow per unit area applications, the winding micro-channels allow a user to customize the pressure drop to promote good flow distribution, to achieve improved heat transfer uniformity, and to enable the pressure drop to remain above the bubble point of the heat transfer structure to prevent gas blockage. The winding micro-channels also improve the heat transfer coefficient.

Heat exchanger having winding micro-channels

A heat exchanger includes a heat transfer surface to transfer heat to or from a working fluid, a manifold region with a plurality of internal walls defining a plurality of inlet and outlet passages, and a heat transfer region disposed between the manifold region and the heat transfer surface. The internal walls are substantially normal to the heat transfer surface for directing working fluid in a normal direction, and include a plurality of alternating inflow and outflow portions in fluid communication with corresponding inlet passages and outlet passages. Adjacent inflow and outflow portions are in fluid communication with each other. A heat transfer structure is disposed in each of the plurality of inflow portions and extend between the internal walls of the inflow portion, the heat transfer structure being in thermal communication with the heat transfer surface to transfer heat between the working fluid and the heat transfer surface.

Normal-flow heat exchanger

A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

Capillary condenser/evaporator

A heat exchanger () includes a core () containing inlet manifold (), outlet manifold (), interconnecting channels () and a heat-transfer surface (). Each interconnecting channel fluidly communicates at one end with a corresponding inlet manifold and at the other end with the two outlet manifolds located adjacent that inlet manifold. The inlet manifolds are located distal from the heat-transfer surface. The interconnecting channels are configured such that substantially all of the heat collected by a working fluid is collected as the working fluid flows from the inlet manifolds away from the heat-transfer surface in a direction substantially normal to the heat-transfer surface.

A heat exchanger (HX) () utilizing a working fluid and having a high heat flux transfer capacity. The HX comprises a core () having a heat transfer surface (), a length and a width. Inlet manifolds () and outlet manifolds () located alternatingly across the width of the core extend the length of the core. Interconnecting channels () each fluidly communicate with a corresponding outlet manifold and the two inlet manifolds located immediately adjacent that outlet manifold. Heat exchanger fin () in thermal communication with the heat transfer surface () generally defines the surface of the interconnecting channels. A pathway directs the working fluid first towards and then away from heat transfer surface (128) in a direction substantially normal to the heat transfer surface. Heat is transferred to or from the working fluid from heat transfer fin () as the fluid flows toward and away from the heat transfer surface.

Heat exchanger

A heat exchanger () comprising a core () containing inlet manifolds (), outlet manifold () and interconnecting channels () and having a heat-transfer surface (). Each interconnecting channel fluidly communicates at one end with a corresponding inlet manifold and at the other end with the two outlet manifolds located immediately adjacent that inlet manifold. The inlet manifolds are located distal from the heat-transfer surface. The interconnecting channels are configured such that substantially all of the heat collected by a working fluid is collected as the working fluid flows from the inlet manifolds toward the heat-transfer surface in a direction substantially perpendicular to the heat-transfer surface.

A capillary evaporator () for removing heat from a heat source (), particularly under high heat-flux conditions. The capillary evaporator includes a housing () having a plurality of ribs () in thermal communication with the heat source when the heat source is present. The ribs define a plurality of vapor channels () for receiving vapor () caused by the vaporization of working fluid () within the evaporator. A capillary wick () is located within the housing in spaced relation to the ribs. A bridge () interposed between the capillary wick and ribs thermally communicates heat from the ribs to the wick and fluidly communicates the vapor from the wick to the vapor channels. The bridge includes a plurality of fractal layers (FL) each having openings () and webs () that are scaled in size and number with respect to the immediately adjacent fractal layer and are arranged so that the openings in adjacent layers overlap one another.

Capillary evaporator

A device ( ) and method for inducing a longitudinal force into a filament ( ) are disclosed. The device includes an enclosure ( ) that defines a chamber ( ) having a first orifice ( ) and a second orifice ( ) located in respective opposing end walls. The filament extends through the first orifice, chamber and second orifice. The area of the first orifice is slightly larger than the transverse cross-sectional area of the filament, and the area of the second orifice is larger than the area of the first orifice. The chamber is filled with a pressurized fluid ( ), which flows out of the enclosure through the first and second orifices, creating corresponding drag forces ( ) on the filament that are in opposite directions to one another. Due to the cross-sectional area of the second orifice being larger than the cross-sectional area of the first orifice, the drag force created by the fluid flowing out of the second orifice is larger than the drag force created by the fluid flowing out of the first orifice, thereby creating a net drag force ( ) in the direction of flow through the second orifice. The net drag force induces a longitudinal force into the filament.

Device and method for inducing a longitudinal force into a filament

A duct is provided having a flattened portion containing a liquid slug of gallium, and a magnetic field is passed through the gallium while an alternating current is also passed through the gallium to produce back and forth motion of the liquid gallium slug in step with the alternating current, enabling compression of working fluid within the duct.

Magnetohydrodynamically-driven compressor

A radial flow heat exchanger (,) having a plurality of first passages (,) for transporting a first fluid (,) and a plurality of second passages (,) for transporting a second fluid (,). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (,) and (,), and surround a central axis (,). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (,). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

Radial flow heat exchanger

A three-phase inverter for small, high speed motors such as a miniature centrifical compressor which has a low voltage, high current requirement. The inverter is supplied with DC power at 28 volts, and produces power of about 50 to 500 watts at about 15 volts, and at frequencies of about 5 to 9 kilohertz. Six D-type flip-flops with clock inputs produce twelve signals which are provided to six bridge drivers. Each bridge driver controls two MOSFET's in series. The MOSFET's are supplied with DC power. Outputs are fed to primaries of adjacent transformers in a circular array. The transformer secondaries are arranged in a star configuration to produce stepped voltage and saw-tooth current output wave forms approximating sinusoids in three phases.

Three-phase inverter for small high speed motors

An electric discharge machining power supply has a capacitor which is recharged using an inductor. After a spark, a transistor switch is closed, and energy from a source is stored in the inductor. The inductor charge period allows for deionization of the spark gap. After the desired amount of energy has been stored in the inductor, the transistor switch is opened, and the energy in the inductor is transferred to a capacitor. When the capacitor is charged, the gap voltage increases to its breakdown value for spark ignition. Because the energy transfer from the inductor to the capacitor is faster than the spark ignition delay, the capacitor is fully charged before the next spark occurs. After the spark ignition delay, a new spark is generated and the cycle is repeated. Other controls and elements are added. Gap voltage is sensed at a point intermediate two resistors between the source and the discharge electrode. A short across the gap is sensed. An inductor/transformer isolates the power source and spark.

Inductor-charged electric discharge machining power supply

The present invention is directed to a compact heat exchanger having a permeable heat transfer element and an impervious heat transfer element. Fluid passes through the permeable element through passages which are substantially normal to the interface between the permeable and impervious elements. The fluid passes into channels which are provided at or near the interface between the permeable heat transfer element and the impervious element. Heat is transferred between the fluid and the permeable heat transfer element by convection as the fluid flows through the permeable element. Heat is transferred between the impervious element and the permeable element by conduction. The permeable element can be formed from one or more plates which bound one or more passages through which the fluid flows or can be formed from various porous material such as sintered powders, rods and metal foams.

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Grantham, NH, United States of America

Javier A Valenzuela