Design and Analysis of the Location of Cold and Heat Sources for the Payload’s Active Thermal Control System on the Lunar Surface

The payload of the Chang’e-4 biological experiment is used as an object for designing and analyzing the location of cold and heat sources. The research compares and analyzes the energy consumption and temperature uniformity of cooling and heating sources mounted on different surfaces using Thermal Desktop/Sinda Fluint, which may be used to guide the design and operation of active thermal control systems. The results indicate that when the hot and cold sources are mounted on the payload’s top surface, the total energy consumption of the active thermal control system is minimized and temperature uniformity is improved.

Small Satellite Operational Phase Thermal Analysis and Design: A Comparative Study

This paper is about the modeling and design of the passive thermal control system for the European Student Earth Orbiter (ESEO) satellite. A detailed thermal model was created in Thermal Desktop software. The model was running for the operative phase which includes cycles of 28 orbits. During these 28 orbits, there are several modes (10 modes). Each mode has a specific duration, attitude (Sun-nadir), and certain internal heat dissipation. The design of the passive thermal control system was based on controlling the conductive and radiative heat exchange between the internal components and the mounting panels, between panels themselves, and controlling external radiation exchange to achieve the desired components temperature ranges. The temperature results from simulations were presented to show the expected component temperatures and to demonstrate that the passive thermal control system met the requirements of the temperature limits. The final passive thermal control design shows that the satellite components temperatures were always maintained within their required limits during the operational phase

Simulation of the thermal control system of nanosatellite using the loop heat pipes under the orbital flight conditions

One of the key problems in the development of nanosatellites is to provide a given temperature range for the operation of the on-board computer. The constantly increasing information load leads to the need to use more advanced processors with high thermal design power (TDP). The indicated thermal regime of processors can be achieved using remote heat removal systems - miniature loop heat pipes. Using a model of nanosatellite as an example, a thermal control system with miniature loop heat pipes is designed. The simulation was carried out in the Siemens NX program in the elliptical and geostationary orbits of the Earth. The cooling schemes of the processor with a thermal power of 15 W using one and two loop heat pipes are considered. Calculations showed that the use of loop heat pipes can reduce the processor temperature to acceptable values. The anisotropy of the thermal conductivity coefficient in the reinforcement plane of the composite material of the nanosatellite case can have a significant effect on the temperature of the processor. This opens up prospects for the use of anisotropic composite materials to ensure the thermal regime of the nanosatellite.

The vibration origin in the electric pump of the spacecraft and methods to reduce them

The important problem for rocket-space, aviation and transport equipment fields is designing high-resource electric pumps. Electric pumps are active energy conversion devices to provide the thermal control system operation. Electric pumps failure leads to fault of the interfaced equipment, system failures and significant economic damage accidents. The most unfavorable factor for electric pump reliability is vibration. That the reason of relevance, practicability and importance to research the electric pumps vibration activity, the reasons for the appearance of vibrations and ways to control them. The paper provides the main sources of electric pump of the spacecraft vibrations as mechanical, hydrodynamic and electrical. This paper presents the recommendations of foreign and domestic authors to control each vibration source. To solve the problem of reducing the electric pump vibration activity the research of the technical level of existing developments, results, main technical solutions and technical solutions trends was produced. The main directions of further electric pump vibration activity researches leading to decreasing of vibration activity were defined on this paper.

A Numerical Study on the Thermal Control of Lithium Batteries by Composite Phase Change Materials and Metal Foams

This study attempts to control the temperature peaks due to the operation of the battery itself by examining a two-dimensional model to numerically investigate the thermal control of a lithium battery of a commercial electric car. The battery has the dimensions of 8 cm × 31 cm × 67 cm and its capacity is equal to 232 Ah with 5.3 kWh. Thermal control is achieved by means of an internal layer of copper or aluminum foam and phase change material (paraffin), placed on the top of the battery and the external surfaces are cooled by a convective flow. The governing equations, written assuming the local thermal equilibrium for the metal foam, are solved with the finite volume method using the commercial code Ansys-Fluent. Different cases are simulated for different thicknesses of the thermal control system and external convective heat transfer coefficient. The results are given in terms of temperature fields, liquid fraction, surface temperature profiles as a function of time and temperature distributions along the outer surface of the battery for the different cases. In addition, some comparisons with pure PCM are provided to show the advantages of the composite thermal control system with PCM inside the metal foam.

A theoretical and experimental study of transient characteristics of the heat exchange in a thermal control system

Introduction. The “Heater-Blower-Room” thermal control system represents three different interconnected subsystems. It is necessary to study the transient characteristics of the heat exchange process, that is underway in the subsystems, including informative impulse responses, to stabilize the system operation. It is a non-parametric problem, and its solution requires identification algorithms. Materials and methods. Mathematical models of the subsystems represent the Volterra integral equation of the first kind with an undetermined difference kernel, or an impulse response. An impulse response evaluation is a solution to this equation in respect of registered noisy input and output values. The problem is to evaluate unknown impulse responses for the subsystems where the output of one subsystem is the input of another one. This problem is ill-posed, and features of identification-focused experiments do not allow to apply computational methods of classical regularization algorithms. The co-authors propose two specific non-parametric identification algorithms where impulse responses are evaluated using stable first derivatives by means of smoothing cubic splines through the optimal smoothing parameter selection on the basis of the statistical optimality criterion. Results. The co-authors solve inverse problems of impulse response identification and direct problems of heat flux reaction prediction. The research results demonstrate a high level of convergence between the evaluated data and observation findings. Both experimental and theoretical results represent the findings of the research performed by the co-authors. Conclusions. The results have proven the efficiency of the algorithms proposed for the identification of solutions to the problems of complex technical systems.