The present application is the National phase of International Application No. PCT/CN2018/107785, titled “ENERGY-SAVING LOOP HEAT PIPE APPARATUS AND APPLICATION”, filed on Sep. 27, 2018, which claims priority to Chinese Patent Application No. 201711311537.X, titled “ENERGY-SAVING TEMPERATURE-CONTROLLED LOOP HEAT PIPE APPARATUS FOR AEROSPACE OPTICAL REMOTE SENSOR”, filed on Dec. 11, 2017 with the National Intellectual Property Administration, PRC, the entire disclosures of which are incorporated herein by reference in their entireties.

FIELD

The present application relates to an energy-saving loop heat pipe apparatus and an application thereof, and belongs to the technical field of thermal control.

BACKGROUND

A temperature-controlled loop heat pipe is an important technology in the field of thermal control of remote sensor, which is mainly used for temperature control of high power imaging circuits (CCD devices, CMOS devices and the like). The temperature-controlled loop heat pipe has the advantages of strong heat transfer ability, stable temperature control performance, no vibration source, mechanical decoupling and so on, and is widely used in the field of thermal control of remote sensor in China.

At present, a power-constant loading mode is adopted for heating loops of the evaporator and preheater of a temperature-controlled loop heat pipe for remote sensing satellites operating in orbit, that is, regardless of whether a remote sensing camera is in an intermittent power-on period (8 minutes) or a long standby period (90 minutes), the heating loops installed at the two positions are closed-loop heated for a long time, and the heat loaded on the loop heat pipe remains unchanged. A vapor phase working medium flowing out of the evaporator of the loop heat pipe is condensed into a liquid phase after being cooled by a radiator, and then transforms into a vapor-liquid two-phase state after being heated by the preheater. Because no heat exchanger is installed between the evaporator and preheater of a conventional loop heat pipe, the working medium flowing into the preheater is not preheated by the vapor phase working medium flowing out of the evaporator, resulting in a certain degree of heat loss of the working medium in the loop heat pipe and a non-maximum use efficiency of the thermal control power.

Because the temperature control power loaded by the evaporator and preheater of the loop heat pipe is finally dissipated into the aerospace through the radiator, a larger temperature control power needs a larger radiator area, and the radiator inevitably becomes heavier, which is contrary to the goal for designing lightweight remote sensors. The conventional loop heat pipe can hardly meet the specification requirements of cameras.

Therefore, the conventional temperature-controlled loop heat pipe has a problem of excessive resource consumption, so it is urgent to carry out targeted optimization design for the conventional temperature-controlled loop heat pipe. Moreover, with the increase of the heating power of CCD devices of the remote sensors, the increase of the number thereof, and the improvement of the temperature index thereof, resources such as the thermal control power and the radiator's weight which are required by the conventional temperature-controlled loop heat pipe are increased, these resources far exceed the bearing capacity of the remote sensing cameras, which become a bottleneck factor restricting the development of remote sensing camera technology.

In order to reduce the thermal control resources consumed by the temperature-controlled loop heat pipe under the premise of satisfying the temperature index of the CCD devices of the remote sensing cameras, it is necessary to carry out a targeted energy-saving design for the loop heat pipe.

SUMMARY

An energy-saving loop heat pipe apparatus and an application thereof are provided according to the present application to overcome disadvantages of the conventional technology. By providing a heat exchanger between an evaporation unit assembly and an capillary pump assembly, the liquid working medium that is about to enter the evaporation unit assembly is heated by the heat of the vapor phase working medium flowing out of the evaporation unit assembly, thereby maximizing the utilization of the waste heat and saving energy.

In order to solve the above technical problem, the following technical solutions are provided according to the present application.

An energy-saving loop heat pipe apparatus includes a capillary pump assembly and an evaporation unit assembly, and further includes at least one heat exchanger arranged between the capillary pump assembly and the evaporation unit assembly for heating a circulating working medium that is about to enter the evaporation unit assembly by using the heat of the circulating working medium itself in a loop heat pipe.

In an optional embodiment, the evaporation unit assembly includes a preheater and at least one evaporation unit, the preheater is used for heating the circulating working medium passing by to a vapor-liquid two-phase state, and the at least one evaporation unit is used for cooling a heat source. The circulating working medium flows through the preheater after flowing through the heat exchanger, and then enters the at least one evaporation unit.

In an optional embodiment, the preheater includes a preheater body and a preheating heating circuit. The preheating heating circuit is arranged outside the preheater body, and is used for determining a heating power according to a temperature of the circulating working medium entering the preheater body and heating the circulating working medium passing by to the vapor-liquid two-phase state.

In an optional embodiment, the preheating heating circuit includes a controller, and a temperature measuring element, and further includes a first stage heating circuit, a second stage heating circuit and a third stage heating circuit which have different powers. The temperature measuring element is used for measuring a temperature of the circulating working medium entering the preheater body, and the controller is used for determining the heating power according to the temperature measured by the temperature measuring element and controlling the heating of the first stage heating circuit, the second stage heating circuit and/or the third stage heating circuit according to the determined heating power.

In an optional embodiment, the heating power of the first stage heating circuit is 3 W to 7 W.

In an optional embodiment, the heating power of the second stage heating circuit is 8 W to 12 W.

In an optional embodiment, the heating power of the third stage heating circuit is 13 W to 17 W.

In an optional embodiment, the preheating heating circuit includes a heating unit, a controller, a flowmeter and two temperature measuring elements, the flowmeter is arranged on a pipeline ahead of the preheater for measuring a flow rate of the circulating working medium in the loop heat pipe, the two temperature measuring elements are respectively used for measuring a temperature of the circulating working medium in a liquid reservoir of the capillary pump assembly and a temperature of the circulating working medium entering the preheater, and the controller is used for determining a heating power of the heating unit according to the flow rate measured by the flowmeter and the temperatures measured by the temperature measuring elements, so that the heating unit heats the circulating working medium passing by to the vapor-liquid two-phase state.

In an optional embodiment, the controller is used for determining the heating power F according to the following equation:
F=(T1−T2)*Q*a+bwherein, T1 indicates the temperature of the circulating working medium in the liquid reservoir, and the unit thereof is Celsius;T2 indicates the temperature of the circulating working medium entering the preheater, and the unit thereof is Celsius;Q indicates a mass flow rate of the circulating working medium in the loop heat pipe, and the unit thereof is g/s;a indicates a constant pressure specific heat of the circulating working medium, and the unit thereof is KJ/(kg Celsius); anda value of b is 1 to 3, and the unit thereof is W.

In an optional embodiment, the energy-saving loop heat pipe apparatus further includes a drive heating circuit arranged on the evaporator of the capillary pump assembly for maintaining or accelerating the flow of the working medium in the loop heat pipe.

In an optional embodiment, the drive heating circuit includes a first drive heating circuit and a second drive heating circuit, the first drive heating circuit is used for maintaining the flow of the working medium in the loop heat pipe in a standby state, and the second drive heating circuit is used for working with the first drive heating circuit to accelerate the flow of the circulating working medium after starting up, and stop working after the apparatus shifts from a power-on state to the standby state for a certain period of time.

In an optional embodiment, the first drive heating circuit has a temperature control power of 28 W to 32 W.

In an optional embodiment, the second drive heating circuit has a temperature control power of 58 W to 62 W.

In an optional embodiment, the energy-saving loop heat pipe apparatus further includes a radiator, the circulating working medium flows out of the evaporation unit assembly and then enters the capillary pump assembly through the radiator, and then enters the evaporation unit assembly through the radiator after flowing out of the capillary pump assembly.

In an optional embodiment, the radiator includes a first flow channel and a second flow channel which are adjacent to each other and independent of each other; an inlet of the first flow channel is in communication with an outlet of the evaporation unit assembly, and an outlet of the first flow channel is in communication with an inlet of the capillary pump assembly; an inlet of the second flow channel is in communication with an outlet of the capillary pump assembly; and an outlet of the second flow channel is in communication with an inlet of the evaporation unit assembly.

In an optional embodiment, the heat exchanger includes a first working medium flow channel and a second working medium flow channel which are adjacent to each other and independent of each other.

In an optional embodiment, the energy-saving loop heat pipe apparatus includes a first heat exchanger and a second heat exchanger, an inlet of the first working medium flow channel of the first heat exchanger is in communication with the outlet of the evaporation unit assembly, an outlet of the first working medium flow channel of the first heat exchanger is in communication with an inlet of the first flow channel of the radiator, an outlet of the first flow channel of the radiator is in communication with the inlet of the capillary pump assembly, the outlet of the capillary pump assembly is in communication with an inlet of the first working medium flow channel of the second heat exchanger, and an outlet of the first working medium flow channel of the second heat exchanger is in communication with an inlet of the second flow channel of the radiator, an outlet of the second flow channel of the radiator is in communication with an inlet of the second flow channel of the second heat exchanger, an outlet of the second flow channel of the second heat exchanger is in communication with an inlet of the second flow channel of the first heat exchanger, and an outlet of the second flow channel of the first heat exchanger is in communication with the inlet of the evaporation unit assembly.

In an optional embodiment, the energy-saving loop heat pipe apparatus further includes a temperature control heating circuit arranged in the liquid reservoir in the capillary pump assembly for heating the liquid reservoir to keep the temperature of the liquid reservoir constant.

The above energy-saving loop heat pipe apparatus can be applied in aerospace optical remote sensors.

Compared with the conventional technology, the present application has the following advantageous effects.(1) By providing the heat exchanger between the evaporation unit assembly and the capillary pump assembly, the energy-saving loop heat pipe apparatus provided by the present application heats the liquid working medium that is about to enter the evaporation unit assembly with the heat of the vapor phase working medium flowing out of the evaporation unit assembly, thereby maximizing the utilization of the waste heat and saving energy;(2) The compensation power consumption of the preheater is indirectly reduced, and the energy is further saved by preheating the circulating working medium through the heat exchanger;(3) The preheating heating circuit provided by the present application realizes instantaneous adjustment and further reduces the thermal control power consumed by the preheater, so that a cycle average value of the power of the heating loop consumed by the preheater is reduced from 15 W to 8 W, which is reduced by 46.7%;(4) By providing drive heating circuits having different powers and adjusting the heating powers of the drive heating circuits according to a working state of the optical remote sensor, the present application reduces a cycle average value of the powers of the drive heating circuits consumed by the evaporator from 90 W to 35 W, which is reduced by 61.1%;(5) The present application reduces an average value of the total thermal control power consumption consumed by the loop heat pipe from 120 W to 58 W, while allowing the CCD (charge coupled device) to meet the temperature index, and the energy saving effect is very notable;(6) Since the thermal control power consumption is finally dissipated to the space through the radiator, after the thermal control power consumption is reduced, an area of the radiator is reduced by 40%, and the weight of the radiator is thereby reduced, which contributes to the weight reduction of the camera; and(7) The overall structure of the present application is compact, is suitable for a variety of working environments, has a relatively long service life, can still operate well under complicated working conditions, has a wide application range, and has a good market application prospect.

