RU2485028C2 - Method of control over spacecraft thermal control system - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to thermal control systems of, mainly, telecommunication satellites. Proposed method comprises periodical telemetry measurements of gas temperature in tight container and rpm of fan motor mounted therein. Gas pressure in tight container is defined from gas temperature measured by remote means with the help of transducers and said motor rpm. Note here that that data are used obtained in preliminary independent fan tests describing the rpm-to-gas pressure ratio.

EFFECT: higher reliability, decreased weight and lower power consumption.

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Description

The invention relates to space technology, in particular to thermal control systems (CTP) of telecommunication satellites.

During the operation of the spacecraft (SC) in orbit for the purpose of diagnosing and predicting normal functioning, in particular, the SRS periodically monitors its operation by measuring the readings of the minimum possible number of telemetric sensors installed onboard the spacecraft: for example, in the case of removal of excess heat generated during the operation of devices installed in an airtight container (STR KA type “Express-A”), by blowing them with the necessary working pressure gas circulated by veins STR emitter, periodically measure the readings of telemetric temperature, pressure (absolute) gas sensors and a tacho sensor (shaft speed sensor) provided as part of the fan motor, and compare it with the permissible values for a given moment in time, determine their speed (pace) changes over time time and establish the operability - the normal functioning of the STR at the moment and predict the operability of the STR during the further operation of the spacecraft (see patents of the Russian Federation (RF) No. 2151721 [1], No. 2164884 [2]).

Thus, for the diagnosis and prediction of the normal functioning of the above type of STR on board the spacecraft, three types of sensors are installed:

- temperature sensors;

- pressure meter;

- tachometer (as part of the fan).

An analysis of the sources of information on patent and scientific and technical literature showed that the closest in technical essence to the prototype of the proposed technical solution is a way to control the operation of the STR KA based on [1].

Figure 1 shows a schematic diagram of the implementation of the above known technical solutions, where: 1 - spacecraft (SC); 2 - a sealed container filled with gas (for example, nitrogen) with a certain working pressure (absolute), in which are installed: devices 3, fan 4 (redundant), radiator 5 (for example, gas-liquid radiator), temperature sensors 6.1-6.4, tachometer 7 (a meter of the number of revolutions of the shaft of the fan motor on which its impeller is mounted), a pressure sensor 9; 8 - telemetry system; 2.1 - gas duct of a sealed container; 2.2 - thermal insulation of a sealed container.

A known method of monitoring the operation of the STR based on [1] includes telemetric measurement of values:

- gas temperature in the area of installation of various devices (according to the readings of temperature sensors);

- gas pressure in an airtight container (as indicated by a pressure sensor);

- the number of revolutions of the working fan impeller as indicated by the tachometer installed in the electric motor (the fan impeller is installed on its shaft).

An analysis of the operating experience of such MFRs showed that in the case of the operability of all the above types of telemetric sensors, reliable control of the normal functioning of the above MFR is provided, i.e. from telemetric measurements of the above parameters it is always possible to establish the value of the heat transfer capacity of the STR at the permissible operating temperatures of the devices and the gas washing them, which should not be lower than the required value.

The analysis also showed that in the event of a failure of the gas pressure sensor (with the operability of all other elements of the CTP), it is not possible to predict the normal operation of the CTP, as the heat transfer capacity of the CTP also depends on the gas pressure: the lower the gas pressure, the lower the heat transfer of the above CTP, all other things being equal.

In addition, the presence of a gas pressure sensor increases the mass of the STR (for example, by ≈ 0.4 kg) and energy consumption (for example, by 1.4 W).

Thus, as follows from the foregoing, significant disadvantages of the known method of monitoring the operation of the CTP are:

- insufficiently high reliability of prediction of the normal functioning of the STR;

- increased mass and power consumption of the STR due to the use of a gas pressure sensor on board.

The aim of the proposed technical solution is to eliminate the above significant disadvantages.

This goal is achieved by the fact that when monitoring the operation of the STA KA during its orbital functioning, periodic telemetric measurements of gas temperatures in an airtight container are carried out, the number of revolutions of the working electric motor of the fan installed in it, while the gas pressure in the airtight container is determined by the measured telemetric value of the number of revolutions of the electric motor fan, using data obtained during preliminary stand-alone tests of the fan in the form of dependence the number of revolutions of the fan motor of the pressure of the gas pumped by it, and compare it with the permissible value, which is, according to the authors, the essential distinguishing features of the proposed technical solution.

As a result of the analysis conducted by the authors of the well-known patent and scientific and technical literature, the proposed combination of significant distinguishing features of the claimed technical solution was not found in the known sources of information, and, therefore, the known technical solutions do not exhibit the same properties as in the claimed method of controlling the operation of the STR KA .

Figure 2 shows a schematic diagram of the implementation of the proposed technical solution, where: 1 - spacecraft (SC); 2 - a sealed container filled with gas (for example, nitrogen) with a certain working pressure (absolute), in which are installed: devices 3, fan 4 (redundant), radiator 5 (for example, gas-liquid radiator), temperature sensors 6.1-6.4, tachometer 7 (a meter for the number of revolutions of the fan motor shaft on which its impeller is mounted); 8 - telemetry system; 2.1 - gas duct of a sealed container; 2.2 - thermal insulation of a sealed container.

The proposed method of controlling the operation of the STR KA, created by the authors on the basis of analysis of test data of existing fans installed in various STR, in a pressure chamber at various gas pressures and temperatures, includes the following operations performed in the following sequence.

1. In the manufacturing process, the fan is installed in a pressure chamber and before switching it on to work, it creates nominal conditions for temperature (t _g ) and gas pressure (R _g ) corresponding to the nominal conditions in an airtight container under orbital conditions, for example, 293 K ( average gas temperature according to the readings of all temperature sensors installed in an airtight container) and 117.68 kPa.

2. Turn on the fan and set on it the rated supply voltage (U _in ) and the nominal pressure (ΔР _in ), corresponding to the rated operating conditions of the fan in an airtight container under orbital conditions (for example, 27 V and 54 Pa).

3. Measure the flow (productivity) (V _in ) and the number of fan revolutions (n _in ) (for example, 100 dm ³ / s and 4500 rpm).

4. The fan is tested in the volume of the above points 1-3 at various gas temperatures and supply voltages (the gas pressure and fan pressure are the initial ones established in paragraphs 1, 2).

5. Test the fan in the amount of paragraphs 1-4, creating in a pressure _chamber according to claim 1 various gas pressures (P _Gi ): from maximum - R _{G max} = 1.2 · R _{G according to claim 1} to a minimum, for example, R _{G min} = 0.1 · R _{G according to claim 1} through a pressure interval, for example, 20 kPa.

6. The measurement data according to claims 1-5 are placed in tables and build dependency graphs

- V _in = f (P _Gi );

- n _In = f (P _Gi ) - see, for example, figure 3,

with the originally installed fan head and with various combinations of t _g = const; U _in = const.

7. During orbital operation, telemetric measurements of gas temperatures are periodically carried out (according to measurements by several temperature sensors, the average gas temperature in a sealed container is determined), the supply voltage of the fan, the number of revolutions of the fan motor and determined using the graphs obtained during tests of the fan in the manufacturing process, the flow rate and pressure of the gas in an airtight container, which should be in acceptable crystals in the case of the normal functioning of the TDB SC.

Currently, experimental work has been carried out with the implementation of the proposed technical solution in the STR KA, the analysis of the data of which showed that the specific value of the gas pressure is reliably determined by the measured value of the number of revolutions of the fan motor for any specific operating condition in orbit, and the pressure sensor is excluded from the composition of the STR KA will provide a reduction in mass of ~ 0.4 kg and energy consumption of 1.4 W and, thus, as follows from the foregoing, thereby achieving the purpose of the invention.

Claims (1)

A method of controlling the operation of the spacecraft thermal control system during its orbital functioning, including periodic telemetric measurements of gas temperatures in an airtight container and the number of revolutions of a working electric motor of a fan installed in it, characterized in that, with the indicated periodic control, the gas pressure in an airtight container is determined by the measured telemetric value fan motor speed using data obtained with autonomous tests of the fan in the form of the dependence of the number of revolutions of the fan motor on the pressure of the gas pumped by it, and compare it with the permissible value.

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