US-12624901-B2 - Thin heat pipe with sintered powdered wick structure

US12624901B2US 12624901 B2US12624901 B2US 12624901B2US-12624901-B2

Abstract

A thin heat pipe including a thin heat pipe container, wick structure, working fluid, and vapor flow passage section is provided. The thin heat pipe container includes a lower inner wall and upper inner wall. The wick structure is disposed on the lower inner wall and includes a first wick structure portion connected to a second wick structure portion. The vapor flow passage section is configured for vapor to flow therethrough. A thickness of the second wick structure portion is lesser than a thickness of the first wick structure portion and the second wick structure portion does not contact, contact points between the upper inner wall and lower inner wall. The wick structure defines the vapor flow passage section. The first wick structure contacts the upper inner wall and second wick structure. Working fluid is pulled from vapor condenser sections to high temperature sections via the wick structure.

Inventors

Xue Mei WANG
Xiao Min ZHANG
Hua-Yuan LIN

Assignees

PURPLE CLOUD DEVELOPMENT PTE. LTD.

Dates

Publication Date: 20260512
Application Date: 20230926
Priority Date: 20220930

Claims (20)

1 . A heat pipe, comprising: a heat pipe container, being sealed, having a lower inner wall, an upper inner wall, a central axis, and a longitudinal center plane, the lower inner wall having a main area portion, a first contact area portion, and a second contact area portion, the lower inner wall extends longitudinal along a length of the heat pipe container, the main area portion extends longitudinal along the length of the heat pipe container between the first contact area portion on one side of the main area portion and the second contact area portion on an opposite side of the main area portion, the upper inner wall extends longitudinal along the length of the heat pipe container and opposite the lower inner wall, a center of the longitudinal center plane is defined by the central axis, the longitudinal center plane intersecting walls of the heat pipe container and defining contact points between the upper inner wall and the lower inner wall, the upper inner wall in contact with the lower inner wall at the first contact area portion and the second contact area portion, respectively, a wick structure formed on the main area portion, the wick structure having at least one first wick structure portion and at least one second wick structure portion the at least one first wick structure portion is in contact with the at least one second wick structure portion and are both disposed longitudinal along the length of the main area portion, the at least one first wick structure portion having a maximum thickness that is greater than a maximum thickness of the at least one second wick structure portion, and a working fluid sealed within the lower inner wall and upper inner wall, wherein the wick structure is not formed on the first contact area portion and the wick structure is not formed on the second contact area portion, wherein the at least a one first wick structure contacts the upper inner wall and the at least one second wick structure does not contact the upper inner wall, wherein a capillary force of the at least one first wick structure is greater than a capillary force of the at least one second wick structure, wherein a mesh count of both the at least one first wick structure portion and the at least one second wick structure portion is between 100 and 120, inclusive.
2 . The heat pipe of claim 1 , wherein a cross-sectional shape of the at least one first wick structure portion is a semielliptical shape.
3 . The heat pipe of claim 2 , wherein a cross-sectional shape of the at least one second wick structure portion is a semielliptical shape.
4 . The heat pipe of claim 3 , wherein an amount of the at least one second wick structure portion is two and one of the at least one second wick structure portion is disposed longitudinal along the length of one side of the at least one first wick structure portion and an other of the at least one second wick structure portion is disposed longitudinal along the length of an opposite side of the at least one first wick structure portion.
5 . The thin heat pipe of claim 2 , wherein a cross-sectional shape of the at least a second wick structure portion is a flat top shape.
6 . The thin heat pipe of claim 5 , wherein an amount of the at least a first wick structure portion is two and an amount of the at least a second wick structure portion is one, and one of the at least a first wick structure portion is disposed longitudinal along the length of one side of the at least a second wick structure portion and an other of the at least a first wick structure portion is disposed longitudinal along the length of an opposite side of the at least a second wick structure portion.
7 . The thin heat pipe of claim 2 , wherein a cross-sectional shape of the at least a second wick structure portion is a vert ramp shape.
8 . The thin heat pipe of claim 7 , wherein an amount of the at least a first wick structure portion is three and an amount of the at least a second wick structure portion is four, and the at least a first wick structure portion and the at least a second wick structure portion are alternatingly disposed longitudinal along the length of the lower inner wall, beginning with a partial end of one of the at least a second wick structure and ending with an opposite partial end of an other of the at least a second wick structure.
9 . The heat pipe of claim 1 , further comprising at least a vapor flow passage section configured for vapor to flow therethrough, wherein an edge of the at least one second wick structure does not contact the contact points between the upper inner wall and the lower inner wall.
10 . The heat pipe of claim 1 , wherein the wick structure is made of sintered metal powder.
11 . A heat pipe, comprising: a heat pipe container, being sealed, having a condenser section, an evaporator section, a central axis, and a longitudinal center plane, the evaporator section having an evaporator lower inner wall having an evaporator main area portion, an evaporator first contact area portion, an evaporator second contact area portion, and an evaporator upper inner wall, the evaporator upper inner wall connected to the evaporator lower inner wall and define a first length, and the condenser section having a condenser lower inner wall and a condenser upper inner wall, the condenser lower inner wall having a condenser main area portion, a condenser first contact area portion, a condenser second contact area portion, and a condenser upper inner wall, the condenser upper inner wall connected to the condenser lower inner wall and define a second length, one end of the evaporator section is in contact with one end of the condenser section and both are longitudinal along a length of the heat pipe container, the evaporator main area portion extends longitudinal along the first length between the evaporator first contact area portion on one side of the evaporator main area portion and the evaporator second contact area portion on an opposite side of the evaporator main area portion, the evaporator upper inner wall extends longitudinal along the first length and opposite the lower inner wall, the condenser main area portion extends longitudinal along the second length between the condenser first contact area portion on one side of the condenser main area portion and the condenser second contact area portion on an opposite side of the condenser main area portion, the condenser upper inner wall extends longitudinal along the second length and opposite the condenser lower inner wall, a center of the longitudinal center plane is defined by the central axis, the longitudinal center plane intersecting walls of the heat pipe container and defining contact points between the evaporator upper inner wall and the evaporator lower inner wall, and defining contact points between the condenser upper inner wall and the condenser lower inner wall, the evaporator upper inner wall is in contact with the evaporator lower inner wall at the evaporator first contact area portion and the evaporator second contact area portion, respectively, the condenser upper inner wall is in contact with the condenser lower inner wall at the condenser first contact area portion and the condenser second contact area portion, respectively, an evaporator wick structure formed on the evaporator main area portion, the evaporator wick structure having at least one first wick structure portion and at least one second wick structure portion, the at least one first wick structure portion is in contact with the at least a second wick structure portion and both are disposed longitudinal along the first length, the at least one first wick structure portion of the evaporator wick structure having a maximum thickness that is greater than a maximum thickness of the at least one second wick structure portion of the evaporator wick structure, a working fluid sealed within the lower inner wall and the upper inner wall and the condenser lower inner wall and the condenser upper inner wall, wherein the evaporator wick structure is not formed on the first contact area portion and the evaporator wick structure is not formed on the second contact area portion, wherein the at least one first wick structure portion of the evaporator wick structure contacts the upper inner wall and the at least one second wick structure portion of the evaporator wick structure does not contact the upper inner wall, wherein a capillary force of the at least one first wick structure portion of the evaporator wick structure is greater than a capillary force of the at least one second wick structure portion of the evaporator wick structur, wherein a mesh count of both the at least one first wick structure portion and the at least one second wick structure portion is between 100 and 120, inclusive.
12 . The heat pipe of claim 11 , further comprising a condenser wick structure, the condenser wick structure is formed on the condenser main area portion, the condenser wick structure having at least one first wick structure portion and at least one second wick structure portion, the at least one first wick structure is in contact with the at least one second wick structure and both disposed longitudinal along the second length, one end of the at least one first wick structure portion of the evaporator wick structure is in contact with one end of the at least one first wick structure portion of the condenser wick structure and one end of the at least one second wick structure portion of the evaporator wick structure is in contact with one end of the at least one second wick structure portion of the condenser wick structure, the at least one first wick structure portion of the condenser wick structure having a maximum thickness that is greater than a maximum thickness of the at least one second wick structure portion of the condenser wick structure, the condenser wick structure is not formed on the condenser first contact area portion and the condenser wick structure is not formed on the condenser second contact area portion, the at least one first wick structure portion of the condenser wick structure contacts the condenser upper inner wall and the at least one second wick structure portion of the condenser wick structure does not contact the condenser upper inner wall, a capillary force of the at least one first wick structure portion of the condenser wick structure is greater than a capillary force of the at least one second wick structure portion of the condenser wick structure, a capillary force of the at least one first wick structure portion of the evaporator wick structure is lesser than a capillary force of the at least one first wick structure portion of the condenser wick structure, and a capillary force of the at least one second wick structure portion of the evaporator wick structure is lesser than a capillary force of the at least one second wick structure portion of the condenser wick structure.
13 . The thin heat pipe of claim 12 , wherein a cross-sectional shape of the at least one first wick structure portion of the evaporator wick structure, a cross-sectional shape of the at least one second wick structure portion of the evaporator wick structure, a cross-sectional shape of the at least one first wick structure portion of the condenser wick structure, and a cross-sectional shape of the at least one second wick structure portion of the condenser wick structure are semielliptical shapes.
14 . The heat pipe of claim 12 , wherein an amount of the at least one second wick structure portion of the evaporator wick structure is two and an amount of the at least one second wick structure portion of the condenser wick structure is two, one of the at least one second wick structure portion of the evaporator wick structure is disposed longitudinal along the length of one side of the the at least one first wick structure portion of the evaporator wick structure and an other of the at least one second wick structure portion of the evaporator wick structure is disposed longitudinal along the length of an opposite side of the at least one first wick structure portion of the evaporator wick structure, and one of the at least one second wick structure portion of the condenser wick structure is disposed longitudinal along the length of one side of the at least one first wick structure portion of the condenser wick structure and an other of the at least one second wick structure portion of the condenser wick structure is disposed longitudinal along the length of an opposite side of the at least one first wick structure portion of the condenser wick structure.
15 . The thin heat pipe of claim 12 , further comprising at least a vapor flow passage section configured for vapor to flow therethrough, wherein an edge of the at least one second wick structure portion of the evaporator wick structure does not contact the contact points between the evaporator upper inner wall and the evaporator lower inner wall, and an edge of the at least one second wick structure portion of the condenser wick structure does not contact the contact points between the condenser upper inner wall and the condenser lower inner wall.
16 . The heat pipe of claim 12 , wherein the mesh count of the evaporator wick structure is greater than a mesh count of the condenser wick structure, and the capillary force of the at least one first wick structure portion of the evaporator wick structure is lesser than the capillary force of the at least one first wick structure portion of the condenser wick structure, and the capillary force of the at least one second wick structure portion of the evaporator wick structure is lesser than the capillary force of the at least one second wick structure portion of the condenser wick structure, so that the working fluid is pulled from the at least one first wick structure portion of the condenser wick structure to the at least one first wick structure portion of the evaporator wick structure, and the working fluid is pulled from the at least one second wick structure portion of the condenser wick structure to the at least one second wick structure portion of the evaporator wick structure.
17 . The thin heat pipe of claim 16 , wherein the mesh count of both the at least one first wick structure portion and the at least one second wick structure portion of the condenser wick structure is between 60 and 80, inclusive.
18 . The heat pipe of claim 11 , wherein the second length is equal to or greater than the first length.
19 . The heat pipe of claim 11 , wherein the first length is at least 10 centimeters or greater.
20 . The heat pipe of claim 11 , wherein the evaporator wick structure is made of sintered metal powder.

Description

RELATED APPLICATIONS This US application claims the benefit of priority to China application no. 202211215143.5, filed on Sep. 30, 2022, of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure is related to the field of heat transfer in general and more particularly but not limited to thin heat pipes with sintered powder wick structures. BACKGROUND OF THE INVENTION Thin heat pipes can be used for thermal control of compact electronic devices with high heat flux and limited space. Heat pipes are passive two-phase heat transfer devices using evaporation and condensation cycles of working fluid to move heat from a heat source on the electronics device to a location spaced away from the heat source, and to quickly cool the heat source, and in turn, the electronics device. Heat pipes can include wick structures disposed within the heat pipes to facilitate movement (e.g., capillary force) of working fluid within the heat pipes, particularly movement of the working fluid from condenser sections of the heat pipes to evaporator sections of the heat pipes. The thermal performance of heat pipes having a wick structure is influenced by induced pressure gradients working to force vapor flow toward the condenser section and capillary liquid flow back toward the evaporator sections. Sintered metal powder capillary structures adhere to inner walls of the heat pipes with high contact, reducing heat resistance between the wick structure and the inner walls of the heat pipes. Generally, a high capillary pressure differential may be achieved with smaller pore radius'. However, accommodation for drops in liquid pressure and higher heat flux transfer may be achieved with larger pore radius'. Determination of the optimal wick structure shape, pore radius', and size and amount of vapor flow passage sections, to facilitate working fluid in a saturated vapor phase to flow towards cooler vapor condenser sections and facilitate working fluid to be pulled from the vapor condenser sections to the evaporator sections, preventing drying out of the working fluid and resulting in high thermal performance of thin heat pipes continue to be a challenge. SUMMARY OF THE INVENTION The present disclosure provides a thin heat pipe including a thin heat pipe container, a wick structure, a working fluid, and at least a vapor flow passage section configured for vapor to flow therethrough. The wick structure is disposed only on a lower inner wall of the thin heat pipe container to minimize thickness of the thin heat pipe. A thickness of at least a second wick structure portion of the wick structure is lesser than a thickness of at least a first wick structure portion of the wick structure and the at least a second wick structure portion does not contact, contact points between an upper inner wall of the thin heat pipe container and the lower inner wall to increase an area of the at least a vapor flow passage section, facilitating the working fluid at high temperature sections (or evaporator sections) of the thin heat pipe in a saturated vapor phase to flow towards cooler vapor condensation sections (or condenser sections) of the thin heat pipe. The first wick structure is in contact with the upper inner wall and in contact with the lesser thickness second wick structure to facilitate working fluid to be pulled from the vapor condensation sections to the high temperature sections, preventing drying out of the working fluid when the working fluid is in a liquid phase at the high temperature sections. In at least one embodiment, the thin heat pipe includes a thin heat pipe container, a wick structure, and a working fluid. The thin heat pipe container is sealed and includes a lower inner wall, an upper inner wall, a central axis, and a longitudinal center plane. The lower inner wall has a main area portion, a first contact area portion, and a second contact area portion. The lower inner wall is longitudinal along a length of the thin heat pipe container. The main area portion is longitudinal along the length of the thin heat pipe container between the first contact area portion on one side of the main area portion and the second contact area portion on an opposite side of the main area portion. The upper inner wall is longitudinal along the length of the thin heat pipe container and opposite the lower inner wall. A center of the longitudinal center plane is defined by the central axis. The longitudinal center plane intersects walls of the thin heat pipe container and define contact points between the upper inner wall and the lower inner wall. The upper inner wall is in contact with the lower inner wall at the first contact area portion and the second contact area portion, respectively. The working fluid is sealed within the lower inner wall and upper inner wall. The wick structure is formed on the main area portion. The wick structure includes at least a first wick structure portion having a first maximum thickn