Совершенствование технологии проведения тепловых испытаний технологического оборудования автономных комплексов

The environmental conditions of autonomous objects of different-purpose technical complexes are in close relationship with increased values of operating temperatures. This requires thermal pretesting of the process equipment. The publication [1] considers the thermal test conditions in which the equipment elements under test are placed in a heated water tank covered by the globe insulators where, under automatic temperature control using a block of heaters, they are then kept for a specified period of time at a specified temperature range. Such an approach to the thermal tests of equipment allows us to reduce, but not eliminate completely the mass flows of water from evaporation with reducing power consumption of test equipment.Despite the results achieved, even a little bit of water vapor available when conducting the thermal tests may cause a failure of equipment. Therefore, there is a need in test equipment modernization for complete eliminating the fluxes of mass water and better power consumption in the test process. To this end, it is proposed to place a three-layer bubble wrap on the open surface of water.To justify an efficiency of the proposed option was developed a mathematical model of heat and mass transfer processes that occur during thermal tests, taking into account the geometric and thermo-physical characteristics of test tank, polymer film, and equipment. Using the laws and equations of heat and mass transfer enabled us to determine the required capacities for heating the tank with water and equipment to the required temperature range for a specified time, as well as the mass flows of water when evaporating from the tank surface.The efficiency of the three-layer bubble film as compared with the globe insulators as the elements for covering the test tank the surface has been analysed on the basis of the results obtained.The proposed film coating allowed almost complete elimination of evaporation losses of water mass and almost 8 times reduction of heat losses through the water surface of the test tank and more than 2 times reduction of power consumption for tests and air-conditioning of the room where these tests were carried out.Условия эксплуатации автономных объектов технических комплексов различного назначения тесно связаны с повышенными значениями рабочих температур. Данное обстоятельство требует проведения предварительных тепловых испытаний технологического оборудования. В работе [1] рассмотрены условия проведения тепловых испытаний, при которых элементы испытываемого оборудования помещаются в резервуар с нагретой водой, накрытый сферическими изоляторами, а затем выдерживаются в течении требуемого времени в заданном интервале температур системой автоматического поддержания температур при использовании блока нагревателей. Подобный способ проведения тепловых испытаний оборудования позволяет снизить, но не исключить полностью потоки массы воды от испарения при уменьшении энергопотребления испытательного оборудования.Несмотря на достигнутые результаты, даже незначительное присутствие паров воды при проведении тепловых испытаний может привести к выводу из строя оборудования. Поэтому существует потребность модернизации испытательного оборудования с целью полной ликвидации потоков массы воды и повышения энергоэффективности в процессе проведения испытаний. С этой целью предложено расположить на открытой водной поверхности испытательной емкости трехслойную воздушно-пузырьковую пленку.Для обоснования эффективности предложенного варианта разработана математическая модель тепломассообменных процессов, возникающих при проведении тепловых испытаний, с учетом геометрических и теплофизических характеристик испытательной емкости, пленки и оборудования. С использованием закономерностей и уравнений тепломассообмена определены мощности, необходимые для нагревания резервуара с водой и оборудованием до требуемого диапазона температур за заданное время, а также потоки массы воды при испарении с поверхности резервуара.На основании полученных результатов проанализирована эффективность применения трехслойной воздушно-пузырьковой пленки по сравнению со сферическими изоляторами в качестве элементов покрытия поверхности испытательного резервуара.Применение предложенного покрытия в виде пленки позволило практически полностью ликвидировать потери массы воды на испарение и почти в 8 раз снизить тепловые потери через поверхность воды испытательного резервуара и снизить более чем в два раза затраты энергии на проведение испытаний и кондиционирование помещения, в котором эти испытания проводятся

Modeling of Rocket Fuel Heating and Cooling Processes in the Interior Receptacle Space of Ground-Based Systems

The propellant to fill the fuel tanks of the spacecraft, upper stages, and space rockets on technical and ground-based launch sites before fueling should be prepared to ensure many of its parameters, including temperature, in appropriate condition. Preparation of fuel temperature is arranged through heating and cooling the rocket propellants (RP) in the tanks of fueling equipment. Processes of RP temperature preparation are the most energy-intensive and timeconsuming ones, which require that a choice of sustainable technologies and modes of cooling (heating) RP provided by the ground-based equipment has been made through modeling of the RP [1] temperature preparation processes at the stage of design and operation of the groundbased fueling equipment.The RP temperature preparation in the tanks of the ground-based systems can be provided through the heat-exchangers built-in the internal space and being external with respect to the tank in which antifreeze, air or liquid nitrogen may be used as the heat transfer media. The papers [1-12], which note a promising use of the liquid nitrogen to cool PR, present schematic diagrams and modeling systems for the RP temperature preparation in the fueling equipment of the ground-based systems.We consider the RP temperature preparation using heat exchangers to be placed directly in RP tanks. Feeding the liquid nitrogen into heat exchanger with the antifreeze provides the cooling mode of PR while a heated air fed there does that of heating. The paper gives the systems of equations and results of modeling the processes of RP temperature preparation, and its estimated efficiency.The systems of equations of cooling and heating RP are derived on the assumption that the heat exchange between the fuel and the antifreeze, as well as between the storage tank and the environment is quasi-stationary.The paper presents calculation results of the fuel temperature in the tank, and coolant temperature in the heat exchanger, as well the heat flows and the relative amounts of the liquid nitrogen used to cool the fuel RG-1 as compared with other cooling technologies.The RP temperature preparation process using a heat exchanger, placed directly in the tank of the filling system is applicable for any high-boiling RP and has some of the best performance characteristics.Modeling the heating and cooling RP processes in the internal tanks of the ground-based systems using the numerical solution of the equations presented can be applied when calculating the RP temperature preparation processes with estimating their effectiveness and time of heating and cooling operations of RP

Improving the Thermal Testing Technology of Technological Equipment of Autonomous Complexes

The environmental conditions of autonomous objects of different-purpose technical complexes are in close relationship with increased values of operating temperatures. This requires thermal pretesting of the process equipment. The publication [1] considers the thermal test conditions in which the equipment elements under test are placed in a heated water tank covered by the globe insulators where, under automatic temperature control using a block of heaters, they are then kept for a specified period of time at a specified temperature range. Such an approach to the thermal tests of equipment allows us to reduce, but not eliminate completely the mass flows of water from evaporation with reducing power consumption of test equipment.Despite the results achieved, even a little bit of water vapor available when conducting the thermal tests may cause a failure of equipment. Therefore, there is a need in test equipment modernization for complete eliminating the fluxes of mass water and better power consumption in the test process. To this end, it is proposed to place a three-layer bubble wrap on the open surface of water.To justify an efficiency of the proposed option was developed a mathematical model of heat and mass transfer processes that occur during thermal tests, taking into account the geometric and thermo-physical characteristics of test tank, polymer film, and equipment. Using the laws and equations of heat and mass transfer enabled us to determine the required capacities for heating the tank with water and equipment to the required temperature range for a specified time, as well as the mass flows of water when evaporating from the tank surface.The efficiency of the three-layer bubble film as compared with the globe insulators as the elements for covering the test tank the surface has been analysed on the basis of the results obtained.The proposed film coating allowed almost complete elimination of evaporation losses of water mass and almost 8 times reduction of heat losses through the water surface of the test tank and more than 2 times reduction of power consumption for tests and air-conditioning of the room where these tests were carried out

Operation modes research of liquefied natural gas storages as a part of the ground complexes equipment

The use of the Liquefied Natural Gas (LNG) in the space-rocket equipment is motivated by some advantages. That is why a lot of tests and works are actively carried out now on rocket engines using liquefied natural gas.To provide the engine tests and subsequent rocket complex operation a creation of LNG storages is demanded as a part of ground processing equipment and support for their safe operation conditions.One of LNG danger factor is its low boiling temperature, and also changing the condition, density and LNG boiling temperature at storage due to evaporation of light component, namely methane. At refill of the storages having fuel remains with a new LNG portion these factors can lead to formation of the stratified macro-layers and cause a mode of the intensive mixing that is called "rollover", with almost instant evaporation of LNG big mass and sharp pressure boost, capable to result in the storage distraction with catastrophic effects.The work objectives are formulated such as a technique development for forecasting of the LNG parameters in operating storages including the rollover mode, a comparison of calculated results of the LNG parameters with the experimental data, and a definition of possible recommendations for safe operation of LNG storages as a part of the ground complexes equipment.The paper reviews 12 publications concerning the issues and proceeding processes at operation of LNG storages, including the rollover mode.To verify the reliability of process simulation results in the LNG, represented in models by the binary methane-ethane mixture the calculated values have been compared with the experimental data for a LNG storage mode in the reservoir of a ground test complex.The reliability of developed models of the heat-mass-exchange processes in stratified on density and temperature in LNG storage with emergence of conditions for the rollover mode has been verified by comparing the settlement characteristics to the published experimental data. The estimated time before a rollover differs from the experimental value by 2,7%. The relative error of other modelled characteristics of LNG does not exceed 2,5%.Conclusions are drawn on the possibility to use the technique based on the thermodynamics equations of irreversible processes in a binary methane-ethane mixture to forecast working parameters of LNG storages operation as a part of the ground complexes equipment. The techniques to except the rollover mode can be based on keeping a stable LNG composition in the storage and arranging the fuel mixing when performing operations of storage refill and its draining from rocket fuel tanks at start cancellation.</p

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Electronic payment systems based on digital money are evaluated in terms of information protection. Mechanisms of protection of interests of bank-emitter, buyer and seller are described. Course of life of a digital denomination is resulted: transactions of removal from the account, purchase and transfer into the account

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