JPS6277594A - Two-phase fluid loop - Google Patents

Abstract

PURPOSE:To make it possible to carry out a remote control transport of a large heat amount and a stable control thereof by fitting a bypass for transporting vapor between an evaporating part provided at the high-pressure side of a main loop for circulating a liquid-phase working fluid by a pump and a condensing part provided at the lower pressure side. CONSTITUTION:A working fluid of a liquid phase within a main loop 5 is circulated by means of a pump 7. A working fluid within a high pressure side 5a is introduced into the main loop 5 by a capillary force of a capillary 3a of the evaporating part 3, and absorbs heat from electronic apparatus in the evaporating part 3 and evaporates. The working fluid of a vapor phase evaporated in the evaporating part 3 reaches a condensing part 1 of a low temperature via a bypass 9. The vapor phase working fluid enters a capillary 3 a on the side of the condensing part 1 because of a difference in pressure between the bypass 9 and the low pressure side 5a, radiated and condensed and again turned into a liquid-phase working fluid, and circulated in the main loop 5 from the low pressure side 1a. Since a drive force is applied to the working fluid by means of the pump 7, it is possible to transport a large amount of heat to a remote distance. Further, since there is no part where the vapor phase working fluid is mixed with the liquid phase working fluid and both fluids flow together, such a phonomenon as fluidication, unstability and the like is prevented from occurring, even at a nongravitational place such as in space.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to a two-phase fluid loop that transports heat through a thermodynamic cycle involving phase changes of evaporation and condensation.

[Technical background of the invention and its problems]

Liquid loops are promising as a heat transport method for space stations and other systems due to their high heat input transport capabilities.

However, single-phase fluid loops use sensible heat to transport heat, so in order to maintain the temperature of the heating part within a narrow temperature range, a large amount of working fluid must be circulated, and pumps, piping, etc. etc., which makes it impractical in terms of weight and pump power.

Therefore, when it is necessary to transport a large amount of heat with a small amount of power and maintain the temperature of the heating part within a narrow temperature range, such as on a space station, it is necessary to transport the heat by using the latent heat caused by the phase change of the working fluid. A two-phase fluid loop is considered advantageous.

In other words, since the two-phase fluid loop utilizes latent heat, the amount of working fluid to be circulated is small, which has the advantage of making piping and pumps smaller and lighter, and requires less circulation driving force, making it fully practical. It is a method. In this two-phase liquid loop, the circulating fluid is sent in a liquid phase to a heat generating part such as an electronic glazer, where it absorbs heat and changes into a vapor phase. This vapor phase is sent to the heat radiating section, where it radiates heat and returns to the liquid phase. Methods for pumping such a two-phase working fluid include, for example, a method using a mechanical pump or a method using a capillary pump.

As a conventional two-phase fluid loop using a mechanical pump, there is one shown in FIG. 5, for example. In other words, this two-phase fluid loop includes a condensing section 1 as a heat dissipation section.
01, an evaporator 1039 as a heat absorbing section, a mechanical pump 105 for driving a working fluid, a regulating valve 107, and the like. Therefore, the evaporator 1 as a heat absorption part
The steam that has absorbed heat from electronic devices and evaporated in step 03 is transported through a pipe to a condenser 101 serving as a heat radiating section, where it radiates heat and is condensed. The condensed liquid is driven by a mechanical pump 105 and is refluxed.

A two-phase fluid loop configured in this way has the ability to transport large amounts of heat over long distances with a small pump, and can be actively controlled by controlling the pump rotation speed and regulating valve operation.・It has the characteristic of being able to respond to large fluctuations in heat quantity. However, in a flow where gas-liquid two phases coexist,
Various flow instability or vibration phenomena are likely to occur. For example, in an evaporator tube, various flow instability phenomena are expected in addition to escape-type instability, in which the flow rate becomes unstable in a region where the pressure loss relative to the increase in flow rate is negative. Also, in the condensing section, for example,
At the part where the steam flows into the supercooled water, it is expected that vibrations will occur due to the condensation of the steam in the liquid. It is extremely difficult to perform stable control on such a fundamentally unstable two-phase fluid loop. Furthermore, since the characteristics of two-phase flow in a zero-gravity field such as in space are unknown, controlling two-phase fluid loops has become a difficult problem. There are also problems with working fluid cavitation, motor lubrication, and reliability.

Therefore, a capillary pump system has been developed, which is a two-phase fluid loop that automatically compensates for the amount of evaporated liquid using capillary force, similar to a heat pipe.

As this capillary pump system, there is one shown in FIG. 6, for example. That is, in this system, a capillary 201a is provided in an evaporation section 201 as a heat absorption section, and liquid in a condensation section 203 as a heat radiation section is drawn in by capillary force.

A capillary pump configured in this manner is characterized in that no external pump power is required to drive the working fluid, and in that it has self-control properties in that only evaporated liquid is supplied. However, since it relies on capillary force for fluid driving force, it has a small liquid transport capacity and has the problem of not being able to transport large amounts of heat or heat over long distances.

[Purpose of the invention]

This invention was devised fj1 in view of the above-mentioned conventional problems, and is a two-phase fluid loop that can transport a large amount of heat over long distances and has stable control characteristics even in a weightless field such as outer space. For the purpose of providing.

[Summary of the invention]

In order to achieve the above object, the present invention has a main loop in which a liquid-phase working fluid is circulated by a pump, and an evaporator section having a capillary structure installed on the high-pressure side of the main loop and to which liquid is supplied from the main loop. A two-phase fluid loop was constructed by a condensing section provided on the low-pressure side of the main loop to return liquid to the main loop, and a bypass transporting vapor evaporated in the evaporating section to the condensing section.

(Effects of the Invention) According to the configuration of the present invention, the driving force for the working fluid in the main loop is provided by the pump, so a large amount of heat can be transported over a long distance, and the liquid evaporated in the evaporation section can be supplied. Since this is carried out in a self-controlled manner by the capillary force of the evaporation section, it can be easily controlled.

Further, since there is no part where the vapor phase and liquid phase mix and flow, stable control can be performed without causing phenomena such as flow instability even in a zero gravity field such as outer space.

[Example of the Invention] An embodiment of the invention will be described below with reference to FIG.

Figure 1 shows a schematic configuration diagram of a two-phase fluid loop. This two-phase fluid loop consists of a condensing section 1 as a heat dissipating section that radiates heat to space, and a condensing section 1 that absorbs heat from electronic devices and evaporates liquid phase working fluid. It has an evaporation section 3 as a heat absorption section, a main loop 5 for circulating a working fluid, a pump 7 for providing driving force for liquid circulation, and a bypass 9.

The evaporator 3 has a capillary tube structure with a capillary 3a, and is connected to the high pressure side 5a of the main loop 5, and the capillary 3a is in contact with the working fluid on the high pressure side 5a. Further, the condensing section 1 also has a capillary 1a to form a capillary structure, and is connected to the low pressure side 5b of the main loop 5,
The capillary 1a is in contact with the working fluid on the low pressure side 5b.

The evaporating section 3 and the condensing section 1 are connected by the bypass 9.

Next, the operation of the above embodiment will be described.

The liquid-phase working fluid in the main loop 5 is given driving force by the pump 7 and circulates through the main loop 5 .

Then, in the evaporation section 3, the working fluid in the high pressure side 5a is introduced by the capillary force of the capillary 3a. The introduced working fluid as a liquid phase absorbs heat from electronic equipment and the like in the evaporator 3 and evaporates. The vapor phase evaporated in the evaporation section 3 is
It passes through a bypass 9 and reaches a low temperature condensing section 1 . In the condensing section 1, the vapor phase enters the capillary 1a on the condensing section 1 side due to the pressure difference between the bypass 9 and the low-pressure side 5a, undergoes heat radiation condensation, becomes a liquid phase again, and returns to the main loop 5 from the low-pressure side 1a.

In the evaporator 3, the same amount of liquid as the evaporated liquid is taken in from the low-pressure side 5a of the main loop 5 by capillary force caused by the capillary 3a.

The pressure displacement of the main loop 5 and bypass 9 at this time is
The state shown in FIG. 2 is reached, and the above operation is confirmed.

In this way, since the working fluid in the main loop 5 is given driving force by the pump 7, a large amount of heat can be transported over a long distance.

Furthermore, since the supply of the liquid evaporated in the evaporation section 3 is performed in a self-controlled manner by the capillary force of the cavity 3a,
Stable control can be easily performed.

Furthermore, since the liquid phase is circulated through the main loop 5 and the vapor phase is passed through the bypass 9, there is no part where the vapor phase and liquid phase mix and flow, so the flow is unstable even in a zero gravity field such as outer space. It is possible to perform stable control without causing such phenomena.

Note that this invention relates to a two-phase fluid loop system, and the structure of the condensing section 1 and the evaporating section 3.

The communication structure between the main loop 5 and the bypass 9 can be arbitrarily configured. For example, using a monogroup heat pipe 11 having a cross-sectional structure as shown in FIG.
It can also be configured as shown in FIG. That is,
The liquid flow path 13 of the monogroup heat pipe 11 is connected to the main loop 5 to constitute the condensation section 1 and the evaporation section 3, and the vapor flow path 15 includes an axial group and a circumferential group forming a capillary structure. It is also possible to have a configuration in which the bypass 9 is connected to the bypass 9.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a two-phase fluid loop according to an embodiment of the present invention, FIG. 2 is a schematic diagram of pressure distribution in each part of the fluid loop according to the configuration of FIG. 1, and FIG. 3 is a diagram of a monogroup heat pipe. 4 is a schematic diagram of a two-phase fluid loop using a monogroup heat pipe, FIG. 5 is a schematic diagram of a conventional Bonpuni phase fluid loop, and FIG. 6 is a diagram of a conventional capillary pump system. It is a schematic configuration diagram. (Explanation of symbols representing main parts of the drawings) 1... Condensing section 3... Evaporating section 5... Main loop 7... Pump 9... Bypass Figure 1 Figure 2 Figure 3 Figure 4 figure

Claims (1)

[Claims] A main loop that circulates liquid phase working fluid with a pump,
An evaporation section having a capillary structure provided on the high pressure side of the main loop and to which liquid is supplied from the main loop, a condensation section provided on the low pressure side of the main loop and refluxing the liquid to the main loop, and vapor evaporated in the evaporation section. A two-phase fluid loop comprising: a bypass for transporting the fluid to the condensing section.