RU2648519C2 - Method of quality control of thermal regulation system of spacecraft - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to thermal control systems (TCS) of spacecrafts (SC). The method of quality control of the SC TCS includes a discharge of the required coolant amount during the filling of the TCS with a heat carrier and further periodic monitoring of the availability of the required mass of the heat carrier in the fluid circuit. For this purpose, the actual fused amount of the heat carrier is measured from the fluid cavity of the volume compensator for the current moment of time, for example, based on the results of the measurement of the heat carrier pressure, temperatures of the heat carrier in the fluid circuit and the working medium in the gas cavity of the volume compensator. The elasticity of the saturated vapour of the working medium is also determined at the measured temperature. After that, the required calculated value of the discharged amount of the heat carrier is determined for the current time. Then, for a given moment of time, the actual amount discharged from the fluid circuit is compared with the calculated amount and the quality of the SC TCS is assessed.

EFFECT: improved quality of manufacturing of the fluid circuit of thermal control systems as a result of providing higher accuracy and reliability of quality control of the fluid circuit in the manufacturing process, ground tests and operation of spacecraft in orbit.

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Description

The invention relates to methods of quality control of a thermal control system (CTP) of a spacecraft (SC), in particular, telecommunication satellites (see patents No. RU 2489330 [1], RU 22009750 [2], RU 2374149 [3]).

As part of the above known technical solutions, the STR contains a closed sealed liquid circuit (see Fig. 1, where pos. 1 - KA; 1.1 - STR; 1.1.1 - liquid circuit; 1.1.2 - volume compensator; 1.1.2.1 - liquid cavity with a coolant; 1.1.2.2 - a gas cavity with a two-phase working fluid; 1.1.2.3 - a bellows; 1.1.2.4 - an electric heater; 1.1.3 - an electric pump unit (ENA); 1.1.4 - a panel on which spacecraft devices are installed; 1.1. 5 - radiator; 1.1.6 - filling valve; 1.1.7 - pressure sensor; 1.1.8 - temperature sensor), filled with a certain required mass of liquid t carrier, for example, LZ-TK-2.

During the manufacturing process, the previously evacuated liquid circuit 1.1.1 CTP is initially completely filled with a deaerated coolant (the bellows 1.1.2.3 is fully compressed and the liquid circuit 1.1.1 is a rigid closed circuit with a maximum volume of coolant) at the ambient temperature in the workshop, maintained in the temperature range (25 ± 10) ° C. After that, the required volume of the dose of the coolant is drained from the liquid circuit, determined on the basis of the formula shown on the next sheet.

The analysis conducted by the authors showed that due to a change in the ambient temperature in the workshop along the height, the temperature of the coolant in the liquid circuit also at different heights in different parts of the liquid path has different values, differing up to (3-5) ° С, and therefore , the coefficient of temperature change in the volume of the coolant and the density of the coolant in the sections also have different values. As the analysis showed, the differences for the coolant LZ-TK-2 reach up to (± 1)% in the range of (25 ± 10) ° С, which is within the limits of permissible error of changes (see pages 14-17 in "T. Bashta. Mashinostroitelnaya hydraulika. Reference book. M.: "Engineering",, 1971 [4]).

Under operating conditions of the spacecraft in orbit, the temperature of the coolant in the sections of the liquid circuit changes, for example, in the range from plus 65 ° С to minus 90 ° С, and, as shown by the analysis of experimental data, the coefficient of temperature change in the volume of coolant at a temperature of + 65 ° С ( the volume of coolant in the liquid circuit has a maximum value) increases by 4%, and at a temperature of minus 90 ° C decreases by 12.5% compared with the experimental coefficient equal to 0.0012 1 / ° C at a coolant temperature of 25 ° C, and accepted constant for the range (25 ± 10) ° С (the corresponding deviations of the coolant density are minus 5% and plus 14%).

And, therefore, in this case, the volume of the drained dose of the coolant is also determined with an increased error, since at present, according to the known technical solutions mentioned above [1], [2], [3], the volume of the drained dose of the coolant for any current moment of time is determined based on the following ratio:

V _{next word} = V _fld + V _J.K. ⋅β⋅ (t _max -t),

where V _ZK - the maximum volume of the liquid circuit filled with the coolant, measured during manufacture, m ³ ;

β = 0.0012 1 / ° C = 0.0012 1 / K is the adopted constant coefficient of temperature change in the volume of coolant in the range Δt = (25 ± 10) ° C or ΔT = (298 ± 10) K;

t _max - the maximum working temperature of the coolant during operation, for example, 65 ° C, at which the maximum volume of coolant in the liquid circuit;

, измеренная перед сливом объема дозы теплоносителя по нескольким датчикам температуры, установленным на жидкостном контуре на различных уровнях (на различных участках), °С.t is the average temperature of the coolant in the liquid circuit

measured before draining the volume of the dose of coolant for several temperature sensors installed on the liquid circuit at different levels (in different areas), ° C.

In addition, since the mass of the coolant in different parts of the liquid circuit is not the same, the average temperature of the coolant is also determined with an error and the drained volume of the dose of coolant is additionally determined with an additional error because of this.

According to the data of the book [4] (see page 16: the text is placed below Fig. 4) "If the liquid is enclosed in a rigid, closed container, the latter may be destroyed" - we have a CTR liquid path made of hard material, closed, sealed, coolant temperature varies under operating conditions in a wide range, for example, from plus 65 ° С in a communication session to minus 90 ° С in standby mode (for spacecraft, the STR of which is made using patent RU 2151722: in order to reduce the power of substitute electric heaters in various modes of operation of the spacecraft ( eg, in standby mode), in the CTP scheme with the radiator panels with double-sided radiation open, a control valve is provided (see Fig. 2), which directs the total flow rate of the heat carrier past the radiator (in this case, electric heaters with reduced heat are required in the circuit with devices where the coolant circulates power) and in it the coolant temperature drops to minus 90 ° C).

Thus, as follows from the foregoing, the well-known technical solution [1] adopted by the authors for the prototype does not provide reliable determination of the required volume of the drained (drained) dose of the coolant in the manufacture of the developed MFR and in the future, when controlling the presence of the required mass of the coolant in the liquid circuit in under operating conditions it provides insufficiently high reliability control of the high-quality production of the STR KA, since at elevated temperature (up to plus 65 ° C) the coolant does not reach the required the dose of the coolant and, consequently, damage to the liquid circuit is possible, and at a low (up to minus 90 ° C) temperature, the measured actual volume of the drained dose of the coolant will be overestimated compared to the required drained dose of the coolant (according to [1]) for a sealed liquid circuit.

The purpose of the proposed technical solutions is to eliminate the above significant disadvantages.

This goal is achieved by the fact that in the method of quality control of the STR, including measuring the maximum volume of the gas cavity of the volume compensator, the volume of sections of the liquid circuit, the maximum volume of the liquid circuit filled with the coolant during their manufacture, periodic telemetric measurements of the temperature of the coolant sections of the liquid circuit and periodic monitoring of the presence of the required mass coolant in a closed sealed liquid circuit of the system during manufacturing, ground testing and operation of the spacecraft in orbit by measuring the current actual value of the volume of the fused dose of the coolant (V _fld.act. ) and comparing it with the required value of the volume of the fused dose of the coolant (V _fld.req. ), when determining the volumes of the fused dose of the coolant initially determine the corresponding average temperature of the coolant (T) in the liquid circuit during the manufacturing process, further ground-based tests and operation of the spacecraft in orbit at current points in time from the condition of equality of the enthalpy of the entire coolant in the liquid circuit D in the sum of the enthalpies of coolant fluid circuit portions according to the formula (1)

then establish the corresponding required value of the volume of the drained dose of the coolant for the current time according to the following relation (2):

where T and T _i are the average temperature of the coolant in the liquid circuit and the temperature of the coolant in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit during manufacturing, ground testing and operation of the spacecraft in orbit at current times, K;

и

- удельная теплоемкость теплоносителя (на основе опытных данных) в жидкостном контуре и в участках жидкостного контура при средней температуре теплоносителя (Т) и температурах теплоносителя (Т_i) в участках жидкостного контура соответственно после слива объема дозы теплоносителя из жидкостного контура в процессе изготовления, наземных испытаний и эксплуатации КА на орбите в текущие моменты времени, Дж/(кг⋅К);

and

- the specific heat of the coolant (based on experimental data) in the liquid circuit and in the sections of the liquid circuit at an average temperature of the coolant (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit in the manufacturing process, ground tests and operation of the spacecraft in orbit at current points in time, J / (kg⋅K);

и

- плотность теплоносителя (на основе опытных данных) в жидкостном контуре при средней температуре теплоносителя (Т) и температурах теплоносителя (T_i) в участках жидкостного контура соответственно после слива объема дозы теплоносителя из жидкостного контура в процессе изготовления, наземных испытаний и эксплуатации КА на орбите в текущие моменты времени, кг/м³;

and

- the density of the coolant (based on experimental data) in the liquid circuit at an average temperature of the coolant (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit in the manufacturing process, ground tests and operation of the spacecraft in orbit at current points in time, kg / m ³ ;

V and V _i are the total volume of the internal cavity of the liquid circuit measured in the manufacturing process and the volumes of the internal cavities of the sections of the liquid circuit filled with coolant at an average temperature (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, at current times, m ³ ;

V _{next word} - the required value of the volume of the drained dose of the coolant for the current time, m ³ ;

V _{housing estate} - the maximum volume of the liquid circuit filled with the coolant, measured during manufacture, m ³ ;

ρ _min - the minimum possible density of the coolant, when the average temperature of the coolant in the entire liquid circuit during production, ground testing and operation of the spacecraft in orbit is the maximum possible, kg / m ³ ,

which is, according to the authors, the essential features of the proposed technical solution by the authors.

As a result of the analysis of the known patent and scientific and technical literature by the authors, the proposed combination of the essential features of the claimed technical solution was not found in the known sources and, therefore, the known technical solutions do not exhibit the same properties as in the claimed method for ensuring the quality of the spacecraft thermal control system.

In FIG. 2 shows a schematic diagram of the implementation of the proposed technical solution, where item 1 - SC; 1.1 - STR; 1.1.1 - liquid circuit; 1.1.2 - volume compensator; 1.1.2.1 - liquid cavity with a coolant; 1.1.2.2 - gas cavity with a two-phase working fluid; 1.1.2.3 - bellows; 1.1.2.4 - electric heater; 1.1.3 - electric pump unit (ENA); 1.1.4 - the panel on which the spacecraft devices are installed; 1.1.5 - disclosed radiator panels; 1.1.6 - filling valve; 1.1.7 - pressure sensor; 1.1.8 - temperature sensor; 1.1.9 - valve regulator.

The proposed method of quality control of STR KA includes the following operations performed in the following sequence:

- establish the brand of the coolant used in the liquid circuit 1.1.1 STR 1.1 KA 1 and its dependence of the density (ρ) and specific heat (with _p ) on the change in the temperature of the coolant (T in degrees Kelvin, which increases the accuracy of processing the experimental data) based on experimental data , for example, in the case of using the coolant LZ-TK-2:

ρ [kg / m ³ ] = 956.12-0.84⋅T [K];

with _p [J / (kg⋅K)] = 636.142 + 4.142857⋅T [K];

(due to the small value of the coolant pressure in the liquid circuit (not more than 200 kPa), the change in the coolant volume depending on the pressure is negligible);

- make components of the STR, including a compensator volume 1.1.2;

- carry out the installation of the STR on the design of the spacecraft 1;

- they check the degree of tightness of the liquid circuit STP 1.1.1 for compliance with the required norm and carry out a complete filling of the previously evacuated liquid circuit with the deaerated coolant LZ-TK-2 (TU38.101388-79);

- measure the temperature of the filled coolant according to several temperature sensors 1.1.8 and determine the average temperature of the coolant in the liquid circuit according to the formula (1)

(This formula was established by the authors on the basis of the theory of enthalpy - see the book "A.V. Bulgarian, G.A. Mukhachev, V.K. Schukin. Thermodynamics and heat transfer. M.," Higher School ", 1975; §3. Enthalpy, pp. 30-31 "[5] and analysis of physical processes occurring in the liquid circuit during the manufacturing process (including during refueling), ground tests and spacecraft operation in orbit);

- they are drained according to [1] in portions of the heat carrier dose, and then, according to (2), the required heat carrier dose is drained from the liquid circuit with high accuracy (± 0.01 dm ³ );

- after that, during the manufacturing process (for example, at the end of the refueling) and periodically during the ground tests and operation of the spacecraft in orbit for the current time moment and for the current average temperature of the coolant, according to [1], the difference between the measured value of the coolant pressure in the liquid circuit and the elasticity value of the saturated steam of the working fluid, partially charged into the gas cavity 1.1.2.2, at the measured temperature of the gas cavity and according to [1] set the current actual value of the fused heat carrier doses (V _rld.actual );

- determine the required value of the volume of the fused dose of the coolant for the current time according to the relation (2)

where in (1) and (2): T and T _i are the average temperature of the coolant in the liquid circuit and the temperature of the coolant in the sections of the liquid circuit, respectively, after the volume of the dose of coolant is drained from the liquid circuit during the manufacturing, ground testing and operation of the spacecraft in orbit in current time points, K;

и

- удельная теплоемкость теплоносителя (на основе опытных данных) в жидкостном контуре и в участках жидкостного контура при средней температуре теплоносителя (Т) и температурах теплоносителя (T_i) в участках жидкостного контура соответственно после слива объема дозы теплоносителя из жидкостного контура в процессе изготовления, наземных испытаний и эксплуатации космического аппарата на орбите в текущие моменты времени, Дж/(кг⋅К);

and

- the specific heat of the coolant (based on experimental data) in the liquid circuit and in the sections of the liquid circuit at an average temperature of the coolant (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit in the manufacturing process, ground tests and operation of the spacecraft in orbit at current points in time, J / (kg⋅K);

и

- плотность теплоносителя (на основе опытных данных) в жидкостном контуре при средней температуре теплоносителя (Т) и температурах теплоносителя (T_i) в участках жидкостного контура соответственно после слива объема дозы теплоносителя из жидкостного контура в процессе изготовления, наземных испытаний и эксплуатации космического аппарата на орбите в текущие моменты времени, кг/м³;

and

- the density of the coolant (based on experimental data) in the liquid circuit at an average temperature of the coolant (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit in the manufacturing process, ground tests and operation of the spacecraft on orbit at current points in time, kg / m ³ ;

V and V _i are the total volume of the internal cavity of the liquid circuit measured in the manufacturing process and the volumes of the internal cavities of the sections of the liquid circuit filled with coolant at an average temperature (T) and temperatures of the coolant (T _i ) in the sections of the liquid circuit, respectively, at current times, m ³ ;

V _{next word} - the required value of the volume of the drained dose of the coolant for the current time, m ³ ;

V _{housing estate} - the maximum volume of the liquid circuit filled with the coolant, measured during manufacture, m ³ ;

ρ _min - the minimum possible density of the coolant, when the average temperature of the coolant in the entire liquid circuit during the manufacturing, ground testing and operation of the spacecraft in orbit is the maximum possible, kg / m ³ ;

- compare the above values V _vld.fact. and V _{next word.} among themselves: if the modulus of difference | V _sld.fact. -V _{next word} | satisfies condition (3)

this means that the liquid circuit is tight and on board the spacecraft in the liquid circuit there is the mass of coolant required to ensure the operability of the spacecraft;

where in (3): ΔV _burr is the measurement error, m ³ (for example, not more than 0.12⋅10 ^-3 m ³ based on experimental data);

V _{reserve.additional leaks} - the coolant reserve provided in the liquid cavity of the volume compensator to compensate for possible leaks from the liquid circuit due to its permissible leak rate provided by the technology, m ³ ;

τ is the point in time under control V _sld.fact. relative to the moment of the start of operation τ _beg , day;

τ _CAC. - the required period of active existence of the spacecraft in orbit, day.

Thus, as follows from the foregoing, the new technical solution proposed by the authors guarantees high-quality production of the STP liquid circuit during the manufacturing process, which eliminates damage to the liquid circuit during further exploitation of the spacecraft, and provides higher accuracy and reliability of the quality control of the STP KA, which is confirmed by the experimental implementation of the proposed technical solution.

Claims (11)

A method of controlling the quality of the spacecraft thermal control system, including measuring the maximum volume of the gas cavity of the volume compensator, the volume of liquid circuit sections, the maximum volume of the liquid circuit filled with the coolant during their manufacture, periodic telemetric measurements of the temperature of the coolant sections of the liquid circuit and periodic monitoring of the presence of the required mass of the coolant in a closed tight liquid circuit system in the manufacturing process, ground tests operating and operating the device in orbit by measuring the current actual value of the volume of the fused dose of the coolant (V _fld.act. ) and comparing it with the required value of the volume of the fused dose of the coolant (V _fldd. ), characterized in that when determining the values of the volumes of the drained dose of the coolant initially determine the corresponding average temperature of the coolant (T) in the liquid circuit during the manufacturing process, further ground tests and operation of the spacecraft in orbit at current times according to the formula (1)

then establish the corresponding required value of the volume of the drained dose of the coolant for the current time according to the following relation (2):

where T and T _i are the average temperature of the coolant in the liquid circuit and the temperature of the coolant in the sections of the liquid circuit, respectively, after draining the volume of the dose of coolant from the liquid circuit during manufacturing, ground testing and operation of the spacecraft in orbit at current times, K;

and

- the specific heat of the coolant, respectively, in the liquid circuit and in the sections of the liquid circuit at an average coolant temperature (T) and coolant temperatures (T _i ), J / (kg⋅K);

and

- the density of the coolant, respectively, in the liquid circuit and in the sections of the liquid circuit at an average temperature of the coolant (T) and coolant temperatures (T _i ), kg / m ³ ; V and V _i - measured in the manufacturing process, the total volume of the internal cavity of the liquid circuit and the volume of the internal cavities of the sections of the liquid circuit filled with coolant, at an average temperature (T) and coolant temperatures (T _i ), m ³ ; V _{next word} - the required value of the volume of the drained dose of the coolant for the current time, m ³ ; V _{housing estate} - the maximum volume of the liquid circuit filled with the coolant, measured during manufacture, m ³ ; ρ _min - the minimum possible density of the coolant, when the average temperature of the coolant in the entire liquid circuit during the manufacturing, ground testing and operation of the spacecraft in orbit is the maximum possible, kg / m ³ .

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