RU2821278C1 - Spacecraft sealed compartments air drying device - Google Patents

Abstract

FIELD: cosmonautics.

SUBSTANCE: invention relates to space engineering, specifically to systems for creating comfortable conditions for crews of space orbital stations during flight. Device for drying air of sealed compartments of spacecraft comprises a prechamber with a fan installed at its top, outlet pipes, condensers, liquid and air-to-air heat exchangers, process cavities formed by bases of condensers and housings of liquid heat exchangers, in each of which there is a thermoelectric cooler based on interconnected thermoelectric modules installed with gaps, which are filled with a non-wettable electric heat insulator, moisture removal device, condensate pumping union and single air path, wherein its design is made on a block principle and consists of an air supply and outlet unit, a condenser unit and a condensate collector unit with possibility of their replacement, wherein temperature sensors are installed on the base of non-finned surface of each capacitor.

EFFECT: increasing the efficiency of a device for drying air in sealed compartments of spacecraft.

1 cl, 4 dwg

Description

The invention relates to the field of space technology, namely to systems for creating comfortable conditions for the crews of space orbital stations during flight.

Long-term operation of modern orbital stations, changes in the number of astronauts on board, a large program of various research and changes in the composition of equipment and apparatus for research lead to changes in humidity loads. As a result, the level of humidity in the compartment may exceed the comfortable conditions necessary for the effective functioning of astronauts. In this regard, it is necessary to maintain the level of air humidity in the habitable compartments of orbital stations in a zone of comfortable conditions.

An air drying device is a type of autonomous air conditioner, the main task of which is to dry the air of sealed compartments of spacecraft (SC).

Unlike ground-based vehicles, where moisture, condensed on the finned surfaces of the heat exchanger, flows into trays under the influence of gravity, in outer space conditions due to the lack of gravity, moisture is collected using a hydrophilic material that absorbs condensed moisture, from which it is pump is pumped into the water regeneration system or into condensate collectors. This is a significant difference in the design of ground and on-board air conditioners.

A known air cooling and drying unit (USSR Author's Certificate N 635366, class F24F 3/14, published 11/30/1978), containing a casing with a prechamber and inlet and outlet pipes, a tubular heat exchanger-condenser, through the pipes of which a coolant is pumped, providing the temperature on the heat exchange surface, necessary for the condensation of excess moisture of the air blown through this surface, a fan, a wick and a moisture collector.

An installation for cooling and drying air is also known (USSR Copyright Certificate N 547591, class F28L 7/00, published 02/25/1977), which contains a casing with a pre-chamber and with inlet and outlet pipes, a tubular heat exchanger-condenser with wicks in the annular space , connected to a moisture collector equipped with a condensate pump and a fan for supplying cooled air.

The specified unit and installation have the following common disadvantages:

- require the presence of a coolant to ensure moisture condensation on the heat exchange surface of the condenser, while for effective air drying, the temperature of the coolant in the inlet manifold of the tubular heat exchanger-condenser should be no higher than 7-10 ° C, the presence of such a temperature level on the supply pipes and fittings laid along habitable compartment, can lead to unauthorized condensation of moisture in various places in the compartment, which will lead to the emergence of sources of dampness and areas of possible development of bacterial flora, all of which worsens the ecology of the crew’s habitat;

- require the presence of a special internal cooling circuit on board the spacecraft to create the required level of coolant temperature at the inlet to the heat exchanger and, therefore, additional fittings, hydraulic connectors, heat exchangers, automation, etc. All this complicates operation and increases the weight of the thermal control system.

The principles of air conditioning using thermoelectric cooling are known, presented in the book by Voronin G.I. and Verba M.I. “Air conditioning on aircraft” (Mashinostroenie publishing house, Moscow, 1965, p. 70, section 3.6 “On-board air conditioning systems on rockets and guided missiles”).

The closest in technical essence to the claimed invention is an air dehumidifier for sealed compartments of spacecraft (RF patent No. 2133920, published on July 27, 1999, IPC: F24F 3/14 (2006.01), F28D 7/00 (2006.01), which is adopted as a prototype. The air dryer includes a casing, in the central part of which there is a device for removing moisture - a rigid wick made of a porous material, made in the form of a plate with a conical base. Inside the casing, opposite each side surface of the plate, a capacitor is installed, made of a material with a high thermal conductivity coefficient, for example, from. aluminum in the form of a base with fins located over the entire area of the base. The ends of the fins are adjacent to the side surface of the plate, and the gaps between the ribs form channels for the passage of air. Opposite each base of the condenser, on the side of its unfinned surface, there is a liquid heat exchanger, and between the base of the condenser and The body of the liquid heat exchanger forms a cavity in which a thermoelectric cooler is placed based on thermoelectric modules connected to each other, which are located with gaps filled with non-wettable electrical insulating material, for example, fiberglass. The hot surfaces of the thermoelectric modules with good thermal contact are adjacent to the liquid heat exchanger shell, and the cold surfaces of the thermoelectric modules with good thermal contact are adjacent to the unfinned surface of the capacitor base. The casing is equipped with a pre-chamber, hermetically sealed on the end surfaces of the bases of the capacitors, and a fan is installed at its top. The cavity of the pre-chamber, channels for the passage of air of capacitors, gaps formed by the ends of the capacitors, the ends of the cavity, free from thermoelectric modules, the volume of which is filled with non-wetted electrical insulating material, the ends of liquid heat exchangers and the inner surface of the base of the device for removing moisture, as well as the gaps between the outer surfaces of liquid heat exchangers heat exchangers and the internal surfaces of the casing opposite them form a single air path connected to the outlet pipes. Between the bottom of the casing and the base of the device for removing moisture, a cavity is formed in which a capillary mesh is placed and which is equipped with a pipe for connecting a pump to it for pumping out condensate.

The disadvantages of the prototype include:

- inability to replace low-resource elements included in the cooler, for example, such as thermoelectric modules;

- the presence of energy consumption of a thermoelectric cooler for cooling the air flow from the temperature at the inlet to the cooler to the temperature required for condensation to form (“dew point”);

- reduced air temperature at the outlet of the thermoelectric cooler, which can lead to a decrease in temperature in the living area of the sealed compartment of the spacecraft and additional energy costs to maintain it at a comfortable level;

- absence of moisture collection from the zone at the base of the ribs of the finned surface of the condenser, which is the zone with the lowest temperature; accordingly, in this zone the most intense loss of moisture from the air will occur, which can lead to flooding of part of the flow area of the condenser air channels and, consequently, to a decrease in flow rate air and moisture removal dehumidifier;

- lack of temperature control of the cooling surface of the condenser; therefore, its temperature may drop below 0°C, which will lead to freezing of the cooling surface and, consequently, to a decrease in the flow area of the air channels of the condenser;

- the need to turn off the dryer when switching the working liquid circuit of the spacecraft to the backup one due to the fact that the liquid heat exchangers are single-circuit.

The objective of the present invention is to create a device for drying the air of sealed compartments of spacecraft, as well as increasing its efficiency.

The technical result is that, in comparison with known technical solutions, the newly created design for drying the air of pressurized spacecraft compartments allows increasing efficiency due to:

- use of heat recovery from cooled and input air flows;

- increasing the temperature of the exhaust air;

- ensuring the selection of the formed condensate from the zone with the lowest temperature;

- organizing separate pumping of condensate from moisture collectors of heat exchangers-condensers and a condensate collector;

- introducing the ability to control the temperature of the cooling surface of the condenser,

- ensuring continuity of operation when switching from the main liquid circuit of the spacecraft to the backup one, therefore, with the same amount of condensed moisture from the air pumped through the device, reduce, in comparison with known designs, the amount of energy consumed, which is very important for spacecraft, where energy consumption is always limited .

The technical result is achieved by the fact that in a device for drying the air of sealed compartments of spacecraft, containing a pre-chamber with a fan installed at its top, outlet pipes, condensers, liquid heat exchangers, technological cavities formed by the bases of the condensers and the housings of liquid heat exchangers, each of which houses a thermoelectric a cooler based on thermoelectric modules connected to each other, installed with gaps filled with a non-wetted electrical insulator, a device for removing moisture, a condensate pumping fitting and a single air path. The design of the air drying device is made according to the block principle and consists of an air supply and outlet unit, a condenser unit and a condensate collection unit with the possibility of replacing them. The air supply and outlet unit includes the mentioned prechamber with a fan located at its top, an air-to-air heat exchanger installed in a single air path between the prechamber and the capacitor unit and made in the form of a counterflow plate heat exchanger with alternating forward and reverse cavities, the heat exchange surface of which can be developed through the use of corrugated liners, while at the outlet of the mentioned direct and reverse cavities cavities are organized without corrugated liners to ensure the division of the air flow into two parts, two cooled air supply ducts installed on the output flanges of the forward stroke of the air-to-air heat exchanger on the outlet side air from the forward stroke cavities, and the mentioned outlet pipes installed on the reverse stroke output flanges of the air-to-air heat exchanger on the side of the air outlet from the reverse stroke cavities, and the pre-chamber is installed on the forward stroke inlet flange of the air-to-air heat exchanger on the air inlet side of the forward stroke cavities . The condenser block includes a plate, two heat exchangers-condensers, each of which consists of a liquid heat exchanger, made double-circuit and containing a housing with fins and an intermediate plate dividing the liquid heat exchanger into two cavities, each of which is connected to the inlet and outlet pipes, two capacitors, each of which is made in the form of a base with ribs, the gaps between which form channels for the passage of air, while part of the finned surface is made with an increased interfin distance for installing additional wicks that allow condensate to be collected in the area at the base of the ribs, two thermoelectric coolers, each of which is located in the mentioned technological cavity, and two moisture collectors, each of which contains a housing that is attached to the liquid heat exchanger and in which the moisture collector wick is placed, while in the moisture collector wick array there is a perforated collector connected to a fitting for pumping out condensate from the moisture collector, and an air duct for supplying cooled and dried air, installed on the said plate between the heat exchangers-condensers, to which the plate is attached from the side where the air enters them. The condensate collection block includes a pallet that performs the function of a casing in which the wick of the condensate collection block is located, while condensate intake devices are installed on the base of the pallet, made in the form of semicircular perforated gutters in cross-section and fixed to the base of the pallet so that between the inner surface of the gutters and the base pan, a condensate pumping cavity is formed, connected to the condensate pumping fittings from the condensate collector block, and the air supply and outlet unit is installed on the condenser block plate, and the condensate collector block is installed on the output flanges of the condenser heat exchangers and the inlet flange of the air supply duct of dried and cooled air from the side air outlet from heat exchangers-condensers. The single air path is formed by the cavity of the prechamber, cavities of the direct passage of the air-to-air heat exchanger, cavities without corrugated liners, cavities of the cooled air supply air ducts, channels for the passage of air in condensers, gaps between the ends of the condenser heat exchangers and the surface of the wick of the condensate collector, the cavity of the dry air supply duct and cooled air, return cavities of the air-to-air heat exchanger, cavities without corrugated liners and cavities of the outlet pipes. The device for removing moisture consists of wicks of moisture collectors, additional wicks for collecting condensate in the area at the base of the fins of the condensers and a wick of the condensate collector block, while temperature sensors are installed on the base of the unfinned surface of each condenser, to which the cold surfaces of the thermoelectric modules of the corresponding thermoelectric cooler are adjacent.

The essence of the invention is as follows.

Humid air from the spacecraft ventilation system is taken by a fan and directed to an air-to-air heat exchanger (AHE), where it is cooled by the reverse flow of dried air. After the HHT, the air enters the condenser heat exchangers (HC), where it is cooled to a temperature below the “dew point” using thermoelectric coolers. Dried cold air comes out of the TC, enters the VVT, is heated by the incoming air flow and returns to the ventilation system of the spacecraft. The resulting condensate is collected using the wicks of the moisture collectors included in the heating system, and is also removed from the heat exchange surface of the condenser by a high-speed air flow and falls on the wick as part of the condensate collection block and is periodically pumped out of it and the moisture collectors by a condensate pump. Heat from the hot junctions of thermoelectric modules (TEMs), which are part of thermoelectric coolers, is removed by pumping the coolant of the liquid circuit of the spacecraft through liquid heat exchangers (LHE) of the TC.

The essence of the invention is illustrated by drawings (Fig. 1-4).

In fig. Figure 1 shows a schematic diagram of a device for drying the air of sealed compartments of spacecraft.

In fig. Figure 2 shows section A-A.

In fig. 3 shows section B-B.

In fig. Figure 4 shows a design diagram of an air-to-air heat exchanger.

In fig. 1-4 the following notations are adopted:

I - air supply and outlet unit;

II - capacitor block;

III - condensate collection block;

1 - air-to-air heat exchanger (AHE);

2 - input flange of direct stroke VVT;

3 - prechamber;

4 - fan;

5 - output flanges of direct stroke VVT;

6 - air ducts for supplying cooled air;

7 - output return flanges of VVT;

8 - outlet pipes;

9 - heat exchangers-condensers (TC);

10 - air duct for supplying dried and cooled air;

11 - plate; 12-pallet;

13 - wick of the condensate collection block;

14 - base of pallet 12;

15 - condensate intake devices (gutters);

16 - condensate pumping cavities;

17 - fittings for pumping condensate from the condensate collection block;

18 - output flanges of heat exchangers-condensers 9;

19 - inlet flange of air duct 10;

20 - cavities of direct stroke of weapons and military equipment;

21 - reverse cavities of military equipment;

22 - corrugated VVT liners;

23 - VVT cavities without corrugated liners;

24 - liquid heat exchangers (HL);

25 - capacitors;

26 - moisture collectors;

27 - housing with fins ZhT 24;

28 - intermediate plate ZhT 24;

29 - cavity of the main liquid circuit (liquid heat exchanger 24);

30 - inlet pipe of the cavity of the main liquid circuit 29;

31 - outlet pipe of the cavity of the main liquid circuit 29;

32 - cavity of the reserve liquid circuit (liquid heat exchanger 24);

33 - inlet pipe of the cavity of the reserve liquid circuit 32;

34 - outlet pipe of the cavity of the reserve liquid circuit 32;

35 - base of capacitor 25;

36 - fins of capacitor 25;

37 - channels for air passage in capacitors 25;

38 - additional wicks;

39 - technological cavity;

40 - thermoelectric coolers;

41 - thermoelectric modules (TEM);

42 - non-wetted electrical heat insulator;

43 - temperature sensors;

44 - moisture collector body 26;

45 - moisture collector wick 26;

46 - perforated manifold;

47 - fittings for pumping condensate from moisture collector 26;

48 - device for moisture removal;

49 - prechamber cavity 3;

50 - cavities of cooled air ducts 6;

51 - gaps between the ends of TK 9 and the surface of the wick of the condensate collector block 13;

52 - cavity of the air duct supplying cooled and dried air Yu;

53 - cavities of outlet pipes 8;

“in1”, “1”, “2”, “out1”, “in2”, “3”, “4”, “out2” - design sections.

The design of the proposed device for drying the air of sealed compartments of spacecraft, shown in Fig. 1-3, is made according to the block principle and consists of an air supply and outlet unit (I), a capacitor unit (II) and a condensate collection unit (III).

The main element of the air supply and outlet unit (I) is an air-to-air heat exchanger (1), installed in a single air path between the prechamber (3) and the condenser unit (II). A pre-chamber (3) is installed on the direct stroke input flange (2) of the air-to-air heat exchanger (1) from the air inlet side of the direct stroke cavity (20), and a fan (4) is installed at its top. Two cooled air supply air ducts (6) are installed on the forward flow outlet flanges (5) of the air-to-air heat exchanger (1) on the side of the air outlet from the direct flow cavities (20). Two outlet pipes (8) are installed on the return return outlet flanges (7) of the air-to-air heat exchanger (1) on the air outlet side from the return stroke cavities (21).

The air-to-air heat exchanger (1) is made in the form of a counterflow plate heat exchanger, in which direct (20) and reverse (21) cavities alternate, the heat exchange surface of which is developed through the use of corrugated liners (22). At the exit of the forward (20) and reverse (21) cavities, cavities without corrugated liners (23) are organized to ensure the division of the air flow into two parts.

The condenser unit (II) includes two condenser heat exchangers (9) and an air supply duct for dry and cooled air (10), installed on a plate (11). Moreover, the heat exchangers-condensers (9) are attached to the plate (11) from the side where the air enters them, and the air supply duct for dried and cooled air (10) is installed on the same side of the plate (11) as the heat exchangers-condensers (9) and is located between them.

Each heat exchanger-condenser (9) consists of a liquid heat exchanger (24), two condensers (25), two thermoelectric coolers (40) and two moisture collectors (26).

Each liquid heat exchanger (24) contains a housing with fins (27) and an intermediate plate (28), dividing the liquid heat exchanger into two cavities (29) and (32), each of which is connected to inlet and outlet pipes (30), (33) and (31), (34) respectively. The cavity (29) of the liquid heat exchanger (24), connected to the inlet (30) and outlet (31) nozzles, is intended for pumping the coolant of the main liquid circuit of the spacecraft, and the cavity (32), connected to the inlet (33) and outlet (34) nozzles , is designed for pumping coolant from the backup liquid circuit of the spacecraft.

Each capacitor (25) is made in the form of a base (35) with fins (36), and the gaps between the fins (36) are formed by channels (37) for the passage of air. Part of the finned surface of the condenser (25) is made with an increased interfin distance for installing additional wicks (38), allowing condensate to be collected in the area at the base of the fins (36) of the condenser (25).

In this case, a technological cavity (39) is formed between the base (35) of each capacitor (25) and the body of the liquid heat exchanger (24), in which a thermoelectric cooler (40) is located based on thermoelectric modules (41) connected to each other (for example, type S- 127-10-15 TU 6341-001-43547909-2009), which are located with gaps filled with non-wetted electrical heat insulator (42) (for example, type Polyurethane System SPU-17 “ZM” according to TU 2254-046-21095499-01). The “cold” junctions of the thermoelectric modules (41) with good thermal contact are pressed against the unfinned surface of the base (35) of the capacitor (25), and the “hot” junctions are pressed against the body of the liquid heat exchanger (24).

Each moisture collector (26) contains a housing (44), which is attached to the liquid heat exchanger (24) and in which the moisture collector wick (45) is placed, while a perforated collector (46) is installed in the moisture collector wick array (45), connected to the condensate pumping fitting from the moisture collector (47).

The condensate collection unit (III) consists of a tray (12), which acts as a casing, in which the wick of the condensate collection unit (13) is located. On the base (14) of the pallet (12), condensate intake devices (15) are installed, made in the form of semicircular perforated gutters in cross-section and fixed to the base of the pallet so that a condensate pumping cavity is formed between the inner surface of the gutters and the base (14) of the pallet (12). (16), which is connected to condensate pumping fittings (17) from the condensate collection block (III).

The air supply and outlet unit (I) is installed on the plate (11) of the capacitor unit (II). A condensate collection unit (III) is installed on the output flanges of the condenser heat exchangers (9) and the input flange (19) of the dry and cooled air supply duct (10) on the air outlet side of the condenser heat exchangers (9).

On the base (35) of the unfinned surface of each capacitor (25), to which the “cold” surfaces of the thermoelectric modules (41) of the corresponding thermoelectric cooler (40) are adjacent, temperature sensors (43) are located (for example, type TM293-02 BY2.821.293TU) .

The assembly principle of the air drying device makes it possible to replace the fan (4) from the air supply and outlet unit (I), the condenser unit (II) and the condensate collection unit (III).

The moisture collector wicks (45), additional wicks (38) and the condensate collection block wick (13) together constitute the moisture removal device (48).

Cavity (49) of the pre-chamber (3), cavities of the direct stroke (20) of the air-to-air heat exchanger (1), cavities without corrugated liners (23), cavities (50) of the cooled air supply ducts (6), channels for air passage (37) in condensers (25), gaps (51) between the ends of the condenser heat exchangers (9) and the surface of the condensate collector wick (13), cavity (52) of the dry and cooled air supply duct (10), return cavities (21) of the air-to-air the heat exchanger (1), the cavity without corrugated liners (23) and the cavity (53) of the outlet pipes (8) form a single air path.

The materials from which most elements of the air drying device can be made are aluminum alloys, for example AMG-6 GOST 4784-97. The wicks of the moisture collectors (45) and the wick of the condensate collector block (13), as well as additional wicks (38) can be made of an open-porous material, for example, porous polyvinylformal grade TPVF-ZBF TU 2244-043-12677854-2007.

A device for drying the air of sealed compartments of spacecraft operates as follows: through the cavities (29) or (32) of liquid heat exchangers (24), the coolant of the main or reserve liquid circuit of the spacecraft is constantly pumped (for example, coolant “TRIOL” TU 0258-004-00205073- 97) (the main and backup liquid circuits of the spacecraft are not shown in the figure), when the humidity in the habitable compartment of the spacecraft increases above the permissible level, the fan (4), thermoelectric modules (41) and the condensate pump (not shown in the figure) are turned on. . The fan (4) begins to pump moist air from the spacecraft compartment through the single air path of the air drying device. When air moves through the forward passage cavities (20) of the air-to-air heat exchanger (1), due to heat exchange with cooled and dried air passing through the reverse passage cavities (21), the air is cooled to the “dew point” temperature, then in the channels (37) condensers (25), the air is cooled due to heat exchange with the cold surface of the condensers (25), and at the same time, excess moisture condenses on the finned surface of the condenser (25). Part of the condensed moisture flows along the ribs (36) of the condenser (25) to the wicks of the moisture collector (45). Due to the action of capillary forces, moisture is absorbed by the porous material of the wicks of the moisture collector (45) and pumped out by a pump through the condensate pumping fittings from the moisture collector (47). Another part of the moisture condensed in the area at the base of the ribs (36) of the condenser (25) is absorbed by the porous material of the additional wicks (38) due to the action of capillary forces and transferred to the wick array of the moisture collector (45). Part of the moisture not absorbed by the wicks of the moisture collector (45) and additional wicks (38) is blown away by the air flow from the finned surface of the condenser (25) and, when the air flow hits the wick of the condensate collector block (13), due to the action of centrifugal forces, falls onto its surface, then, due to the action of capillary forces, moisture is absorbed by the porous material of the wick of the condensate collection block (13) and pumped out by a condensate pump (not shown in the figure) through the condensate pumping fittings from the condensate collection block (17). Cooled and dried air through the gaps (51) and cavity (52) enters the return cavities (21) of the air-to-air heat exchanger (1), where, due to heat exchange with moist air, it allows the temperature of the latter to be reduced to the “dew point” and through the outlet pipes (8) is released into the space station compartment, where it is mixed with the compartment air. As a result of this mixing, the air humidity in the compartment gradually decreases and when a given humidity level is reached, the thermoelectric modules (41), the fan (4) and the condensate pump (not shown in the figure) are turned off.

During operation of the air drying device, it is possible to control the temperature of the base (35) of the condenser (25) according to the readings of the temperature sensors (43). When the temperature of the base (35) of the capacitor (25) approaches zero values, power is removed from the thermoelectric modules (41) of the thermoelectric cooler (40) adjacent to the corresponding capacitor. When this temperature rises to values that prevent freezing of the heat exchange surface of the condenser (25), the power supply to the thermoelectric modules (41) of the corresponding thermoelectric cooler (40) is restored. In this case, the fan (4) and thermoelectric modules (41) of the remaining thermoelectric coolers (40) remain turned on.

Due to the fact that the liquid heat exchangers (24) are dual-circuit, when switching from the main to the reserve liquid circuit of the spacecraft, the operation of the air drying device is not interrupted.

Separate pumping of condensate from the wicks of the moisture collectors (45) and the wick of the condensate collector (13) promotes more complete drying of the wicks during operation of the condensate pump and, consequently, an increase in the productivity of the air drying device.

Thermal calculations show that using such a device it is possible to achieve moisture removal of 500 g/h under the following conditions:

- supply voltage of thermoelectric coolers (40) is 27 V;

- the total coolant flow rate of the main or backup liquid circuit of the spacecraft through the cavities (29) or (32) of the liquid heat exchangers (24) is 110 cm ³ /s;

- the temperature of the coolant of the main or backup liquid circuit of the spacecraft at the entrance to the cavities (29) or (32) of the liquid heat exchangers (24) is no more than 19°C;

- air flow through a single air path is 40 l/s;

- the air temperature at the entrance to the single air path is no more than 21°C;

- the relative humidity of the air at the entrance to the single air path is at least 70%.

To achieve a given moisture removal, it is necessary to cool the air to a temperature of 10.6 ° C, and 862 W of heat will be consumed.

With a supply voltage of thermoelectric coolers (40) of 27 V and the assumption that a temperature difference of 20°C is realized between the “hot” and “cold” junctions of thermoelectric modules (41), the amount of heat absorbed at the “cold” junction of one thermoelectric module of type S- 127-10-15

TU 6341-001-43547909-2009 (according to the passport data) is 7.3 W, and its energy consumption is 5.6 W. Thus, in the absence of VVT (1), part of the thermoelectric modules (41) will work to cool the air to temperature of the “dew point”, and in this area there will be no loss of moisture from the air. In this case, it will be necessary to use 118 thermoelectric modules, and their total energy consumption will be about 660.8 W. The air temperature at the device outlet in this case will be 10.6 ° C.

To cool an air flow with a temperature of 21°C and a relative humidity of 70% with a flow rate of 40 l/s to the “dew point” (15.3°C and 100%), it is necessary to remove 280 W of heat from it. The use of regeneration between the cooled air at the outlet of the condenser block (II) and the humid air at the inlet using VVT (1) allows the temperature of the air at the inlet to the condenser block (II) to be reduced to the “dew point”. In this case, to achieve a given moisture removal, it is necessary to use 80 thermoelectric modules, and their total energy consumption will be about 448 W. Also, the air temperature at the outlet of the device rises to 16.1°C.

Thus, the use of VVT (1) makes it possible to reduce the required number of used thermoelectric modules (41), which reduces the weight and size characteristics of the heat exchanger-capacitors (9) and reduces the total energy consumption of the device for air drying. In addition, the use of a VVT air drying device (1) in the design makes it possible to increase the output air temperature from 10.6 to 16.1°C. Such heating would require spending an additional 280 W from on-board electric heaters.

Under given conditions, energy consumption for air drying is reduced by half.

The calculation diagram of the weapons and military equipment for determining its thermal characteristics, indicating the design sections, is presented in Fig. 4.

In fig. 4, the “forward stroke” is taken to be the VVT cavity into which hot air is supplied, and the “reverse stroke” is the VVT cavity into which cold air is supplied.

To calculate thermal characteristics, weapons and military equipment can be divided into three characteristic sections:

- in the “calculation section I”, the forward air of the air and military equipment moves in the channels of the corrugation, and the reverse air of the air and military equipment moves in the cavity of the air and military equipment without a corrugated liner;

- in the “design section I” the forward and reverse air of the weapons and military equipment moves in the corrugation channels;

- in the “calculation section III” the forward air of the air and military equipment moves in the cavity of the air and military equipment without a corrugated liner, and the reverse air of the air and military equipment moves in the channels of the corrugation.

On the one hand, for “calculation section I”, the heat removed from the forward air of the weapons and military equipment is equal to the heat supplied to the reverse air of the weapons and military equipment. Accordingly, for “calculation section I” a balance equation (1) can be drawn up:

On the other hand, for “calculation section I” a balance equation (2) can be drawn up:

Where - heat transfer coefficient for “design section I”, W/K;

- logarithmic temperature difference for “design section I”, °C.

Similar equations can be drawn up for “calculation section II” and “calculation section III”:

The solution of the system of equations (1) - (6) allows us to determine the calculated heat removal of the military equipment. For the given conditions, the heat removal of the VVT will be 290 W. Thus, the proposed design of the VVT makes it possible to cool the incoming air to a temperature of 15.3°C.

As part of the capacitor block (II), heat exchangers-capacitors (9) are installed in parallel, both along the air flow and along the coolant of the main or backup liquid circuit of the spacecraft. Accordingly, to achieve a moisture removal rate of the air dryer of 500 g/h, one heat exchanger-condenser (9) must remove at least 250 g/h under the following conditions:

- supply voltage of thermoelectric coolers (40) is 27 V;

- the coolant flow rate of the main or backup liquid circuit of the spacecraft through the cavities (29) or (32) of the liquid heat exchangers (24) is 55 cm ³ /s;

- the temperature of the coolant of the main or backup liquid circuit of the spacecraft at the entrance to the cavities (29) or (32) of the liquid heat exchangers (24) is no more than 19°C;

- air flow through the air channels (37) of the heat exchanger-condenser (9) is 20 l/s;

- the air temperature at the entrance to the air channels (37) of the heat exchanger-condenser (9) is no more than 15.3°C;

- the relative humidity of the air at the entrance to the air channels (37) of the heat exchanger-condenser (9) is at least 100%.

The method for calculating a thermoelectric cooler taking into account the presence of thermal resistance on the side of the “hot” and “cold” junctions of the TEM is given in the book by Kaganov M.A., Privin M.R. “Thermoelectric heat pumps (theoretical basis of calculation)” (Energia Publishing House, Leningrad, 1970, p. 174).

The heat absorbed by the “cold” junction of one TEM in the absence of thermal resistance between the cooled medium and the “cold” junction of the TEM is determined by formula (7):

where R _tem is the electrical resistance of the TEM, Ohm;

I is the current strength passing through the TEM, A;

e _tem ~ the value of thermo-emf developed by the TEM,

T _g - temperature of the hot junction of the TEM, K;

ΔT - temperature difference between the hot and cold junctions of the TEM, K;

λ _tem - thermal conductivity coefficient of TEM,

S _tem - surface area of one TEM junction, m ² ;

d _tem ~~ TEM thickness, m ² ;

The heat released at the hot junction of one TEM in the absence of thermal resistance between the cooling medium and the hot junction of the TEM is determined by the formula:

For convenience of calculations, formulas (7) and (8) can be written in dimensionless form:

Where - dimensionless specific cooling capacity/heating capacity per unit area of the TEM;

- dimensionless current density passing through the TEM;

- dimensionless temperature of the “cold”/“hot” junction of the TEM;

- dimensionless temperature difference between TEM junctions;

Formulas (7a) and (8a) are valid in the absence of thermal resistance at the TEM junctions.

In the presence of thermal resistances from the “cold” and “hot” junctions of the TEM, the heat balance for the TEM in dimensionless form can be written as follows:

Where

- dimensionless air/coolant temperature of the main or backup liquid circuit;

- dimensionless temperature difference between the air and the coolant of the main or backup liquid circuit;

- Biot criterion for the “cold”/“hot” junction of the TEM;

k _x,g - reduced heat transfer coefficient from the side of the “cold”/“hot” junction of the TEM,

The solution of the system of equations (9)-(10) allows us to determine the calculated moisture removal of the TC. For the given conditions, the moisture removal of one TC will be 278 g/h.

The air drying device has been manufactured and has undergone part of the autonomous testing as part of laboratory development tests with positive results.

Claims (1)

A device for drying the air of sealed compartments of spacecraft, containing a pre-chamber with a fan installed at its top, outlet pipes, condensers, liquid heat exchangers, technological cavities formed by the bases of the condensers and the housings of liquid heat exchangers, each of which houses a thermoelectric cooler based on thermoelectric ones connected to each other modules installed with gaps that are filled with a non-wetted electrical heat insulator, a device for removing moisture, a condensate pumping fitting and a single air path, characterized in that its design is made according to the block principle and consists of an air supply and outlet unit, a capacitor unit and a condensate collection unit with the possibility of their replacement, while the air supply and outlet unit includes the mentioned prechamber with a fan located at its top, an air-to-air heat exchanger installed in a single air path between the prechamber and the capacitor unit and made in the form of a counterflow plate heat exchanger with alternating forward and reverse cavities , the heat transfer surface of which can be developed through the use of corrugated liners, while at the exit of the mentioned direct and reverse cavities, cavities are organized without corrugated liners to ensure the division of the air flow into two parts, two cooled air supply ducts installed on the output flanges of the forward air stroke - an air heat exchanger on the side of the air outlet from the forward cavities, and the mentioned outlet pipes installed on the return flanges of the air-to-air heat exchanger on the side of the air outlet from the return cavities, and the pre-chamber is installed on the inlet flange of the forward stroke of the air-to-air heat exchanger on the side air inlet into the direct flow cavities, the capacitor block includes a plate, two heat exchanger-condensers, each of which consists of a liquid heat exchanger, made double-circuit and containing a housing with fins and an intermediate plate dividing the liquid heat exchanger into two cavities, each of which is connected to the inlet and output pipes, two condensers, each of which is made in the form of a base with ribs, the gaps between which form channels for the passage of air, while part of the finned surface is made with an increased interfin distance for installing additional wicks, allowing condensate to collect in the area at the base of the ribs, two thermoelectric coolers, each of which is located in the mentioned technological cavity, and two moisture collectors, each of which contains a housing that is attached to the liquid heat exchanger and in which the moisture collector wick is located, while a perforated collector is installed in the moisture collector wick array, connected to a fitting for pumping out condensate from moisture collector, and an air duct for supplying cooled and dried air, installed on the said plate between the heat exchangers-condensers, to which the plate is attached from the side where the air enters them, the condensate collection unit includes a tray that performs the function of a casing, in which the wick of the condensate collection unit is located, while On the base of the pallet, condensate intake devices are installed, made in the form of semicircular perforated gutters in cross-section and fixed to the base of the pallet so that a cavity is formed between the inner surface of the gutters and the base of the pallet, connected to the fittings for pumping out condensate from the condensate collector, and an air supply and outlet unit is installed on the plate of the condenser block, and the condensate collector block is installed on the output flanges of the condenser heat exchangers and the inlet flange of the air duct for supplying dried and cooled air on the side of the air outlet from the condenser heat exchangers, a single air path is formed by the cavity of the prechamber, the cavities of the direct flow of the air-to-air heat exchanger, the cavities without corrugated liners, cavities of cooled air supply air ducts, channels for air passage in condensers, gaps between the ends of the condenser heat exchangers and the surface of the wick of the condensate collector, cavity of the dry and cooled air supply duct, return cavities of the air-to-air heat exchanger, cavity without corrugated liners and cavities of the outlet pipes, the device for removing moisture consists of wicks of moisture collectors, additional wicks for collecting condensate in the area at the base of the fins of the condensers and a wick of the condensate collection block, while on the basis of the unfinned surface of each condenser, to which the cold surfaces of the thermoelectric modules of the corresponding thermoelectric cooler are adjacent, Temperature sensors are installed.