Transport line with grooved microchannels for two-phase heat dissipation on devices

Abstract

Grooved microchannels are used to enhance the capillary action in the transport line of two-phase heat dissipation devices, such as loop heat pipes, capillary pump loops, or spray cooling devices, or others. Efficient heat dissipations achieved by enhancing the capillary pumping force for the liquid flow without significantly increasing the friction force. The effective cross-sectional area of the liquid line is made smaller than that of the condensation section, either by inserting a plug or shrinking the liquid line, to provide additional pumping force for the coolant recycling.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention related to two-phase heat dissipation devices, particularly to the transport line of loop heat pipes, capillary pump loops, spray cooling devices or others. The two-phase heat dissipation device is sued for heat removal of heat generating devices, such as the central processing unit (CPU) or other integrated circuit (IC) chips. [0003] 2. Brief Description of Related Art [0004] As electronic technology advances, more electronic function is performed in a smaller area on a semiconductor chip. More electronic function is invariably accompanied with temperature increase which may damage the chip. To maintain a safe temperature, it is necessary to remove the heat generated in the chip at the chip mount. [0005] A widely used method for cooling the chip mount is to utilize the two-phase heat transfer during phase transition between liquid phase and vapor phase of a coolant. In this method, a vaporization sect...

AI Technical Summary

Benefits of technology

[0008] The object of this invention is to provide efficient flow of a coolant in a transport line for loop heat pipes, capillary pump loops or spray cooling devices. Another object of this invention is to provide additional pumping force for the liquid flow without significantly increasing the friction force.

[0009] These objectives are achieved by using grooved microchannels in the liquid line. Grooved microchannels can be optionally made in the inner surface of the condensation section. Further, a plug can be inserted in the liquid line to reduce its effective cross-sectional area to enhance the pumping force. Another way is to shrink the liquid line section to reduce its effective cross-sectional area to enhance the pumping force. The grooved microchannels in the liquid line provide additional pumping force for coolant recycling with limited friction force.

Problems solved by technology

More electronic function is invariably accompanied with temperature increase which may damage the chip.

In this method, a vaporization section vaporizes the coolant and carries away a large amount of heat energy, and the vapor fills the originally evacuated space.

This impedes the recycling capillary pumping action and tends to limit the maximum heat dissipation capability of the heat pipe.

The drawback of this structure is that the wicks in the condenser 218 and the liquid line 214 increase the friction to the liquid flow and hence retard coolant recycling.

Therefore, the evaporator tends to dry out at high heat dissipation and limit the heat cooling capability.

When the liquid section and the vapor section use the same large tubing, the liquid line cannot provide additional capillary force.

If both sections use the same small tubing, the vapor speed and the friction in the vapor line becomes excessive.

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